The Legend of Spooky Bites.

”…it is far harder to kill a phantom than a reality.”  -Virginia Woolf

I am a craftsman of the jaw-closing business. Every day I make restorations to the teeth of  patients of mine. After this intervention, it is the fundamental trick of my trade to make my patients close their mouth in a relaxed manner. Like a skilled carpenter, who is specialized in fixing doors and door-frames, so that the door closes unobstructed, I earn the trust of my patients by making them close their mouth effortlessly.  After each restoration, I spend 5 to 10 minutes painstakingly adjusting the form of the restoration so that it does not interfere with jaw-closing and lateral movements of the mandible. It is not always an easy task, as I have explained earlier in my blog article “The Soundbites of Sound Bites” and “Filibustering in the House of Parliament of Occlusion”. Too much occlusal force in the front teeth area alerts the jaw-closing muscles to switch off, whereas too much occlusal force in the back teeth area enhances jaw-closing activity.

The Tscan system was an answer to my prayers to find a better tool to assess the bite forces hitting the restorations I have made. I was amazed to find out, that the ink marks of bite foil were only a vague, unreliable hint of the actual forces taking place in the occlusal contact points of dentition. Very often, a microscopic, barely discernible wispy dot would have been the spot of extreme bite forces. That was why the filling that I had made six months earlier, before I had a Tscan in my disposal, had become chipped to pieces. Previously, having relied myself on the appearance of the ink marks of the bite foil only, I had been securing myself to a false sense of security.

With the advent of Tscan, however, another problem emerged, of what I had previously not had any idea of.

I was disappointed to find out that a subset of my patients, despite my meticulous adjusting of the occlusal contact forces, were extremely reluctant to show a steady bite force graph. For some individuals the Tscan movies looked like perfect nonsense. At first, I thought to myself, maybe I was just not doing the measurements properly. The max force curve of the Tscan movies showed wobbly jaggedness. It looked like a tremor, it couldn’t be a relaxed bite. Three microseconds of closing followed by three microseconds of opening activity. It looked like the closing down and opening muscles would be undergoing a tug-of-war. How many times ever I repeated the scans, and however much time I spent equilibrating the tooth contacts I was unable to make this subset of my patients to perform the beautiful, healthy max force curves with an initial steady rise from the first time point of contact “A” to the maximal amount of contacts at time point “B”, and thereafter to remain close to the 100% force all the way to the point “C”.

I was perplexed. Some of these patients might say that they sometimes felt like their bite would be ”popping off”, yet most of these patients often would say that their bite felt OK. At recall visits I could see that everything was not alright. There was chipping and wear down of the fillings and tooth surfaces. At first, I could not give a rational explanation why an apparently perfect jaw closing brings about such a muscular tremor. That was spooky.

It was a kind of thing what a carpenter would feel like when visiting a house where a little earlier he had renovated the crooked old doors and door-frames, and now he would see the wear down of door-frame paint at the very spots he had renovated and painted. It is an uneasy feeling that sometimes makes you ponder and sometimes it makes you wake up shivering in the middle of the night. The owner of the house would have said that the door the carpenter had fixed, kept opening up by itself and it was likely that the old house was, in fact, haunted.

A true craftsman is reluctant to accept supernatural powers to interfere with his trade. Nevertheless, what it comes to the sciences of occlusion, the physically unexplained phenomenon of non-matching of the dentition has been given the epitome of “the phantom bite syndrome”. By the latter half of 70’s this description was given to individuals who:

“…seek bite correction from a succession of dentists. Their pathological narcissism focuses on their bite, in a manner reminiscent of phantom limb phenomena.”

Reports have been written to scientific journals where the authors have not been able to find any specific clinical fault in this kind of patient´s dentition, despite that affected individuals typically complain of their “bite being off”. The Phantom Bite -condition still seems to be a feasible term to describe the subset of TMJ patients who respond poorly to treatment efforts of bite doctors.

Carpenters are more down to earth style of persons and they very quickly pick up their water-levels and give a diagnosis to the master of the house. The door frame, that was perfectly level six months ago is not level any longer. The problem of the door popping open by itself is not due to due to ghosts, but a failure in the foundation of the whole building. The corner of the house has been tilting all the time and now all the rest of the structures of the building are tipping off the level, respectively. Also, the hinges of the door may be worn and slackened by the strain. Slack hinges allow different spots of the door to hit the door frame each time the door is slammed to close.

A bite doctor should not forget that the dental occlusion system is analogous to a door and door frame system by actually there being two points of reference. There is the “door and the door-frame variable” that can be measured exactly from a Tscan movie. We can create a perfect match between the upper and lower jaw by altering the form of the occluding teeth. The second variable of jaw-closing, the “door hinge variable” can’t be directly operated on. The wobbles and the jaggedness of the max force curve in a Tscan movie reveals that there is uncomfortable variability in the way that the mandible meets the upper jaw. There is slackness in the rotational and translational movements of the condyle head in the glenoid fossa. In multiple subsequent bites unpredictable and different sets of teeth occlude. The direct mechanical repair of the jaw-joints is out of our means. Unlike carpenters, who can just change the worn out hinges of the door, the bite-doctors do not have any immediate tools to work on the hinge -parts of the bite-system.

We can’t touch the broken hinge, but that does not mean that we could ignore it. We must be honest to our patients and we should not disguise our ignorance trying to convince the unlearned patient by vague explanations of “phantom bite”. I can’t go telling to my patient that actually you don’t have any pain, you just feel like you would, and it is just about your pathological narcissism that has become focused to your dentition…

However, the wonders of nature may go beyond the phantasms of the supernatural.

Unlike the worn down door hinge, the human jaw-joint has a wonderful self-repairing capacity. With patience and regular check-ups and correction of digitally measured occlusal contact forces, a skilled craftsman of the dentition can be able to gradually relieve the strain from the damaged joint-tissues. The jaw-joint can be healed. I have managed to straighten out the wobbles and tremors of the Tscan max force curves of many of my patients.

Sign up to follow my blog to read my future articles where I explain how I do heal my patients with spooky bites.

Kymmenen minuuttia, jotka järisyttivät maailmaa

albin

Kirjoitan tätä tammikuun lopussa 2017, kymmenen päivää Yhdysvaltain presidentin virkaanastujaisten jälkeen.

Tulin juuri Helsingistä hands-on kursseilta. Olen äärimmäisen kiitollinen tohtori Robert Kersteinille. Jälleen kerran hän oli sietänyt Atlantin ylilennon rasitukset ja Suomen keskitalven subarktisen sumun ja synkkyyden. Me kurssin osallistujat saimme nauttia hyvästä suojasta ulkomaailman koleutta ja arvaamattomuutta vastaan. Vallankumouksellinen innostus leijaili kahvinkeittimen vaiheilla Albin-hammasklinikan tyylikkäässä ja viihtyisässä aulassa. Albin on digitaalitekniikkaan orientoituneiden Satu ja Kai Aallon vastaanotto Helsingin Kalliossa. Potilaiden odotushuoneesta oli improvisoitu luentosali, missä saimme seurata Robert Kersteinin potilastyöskentelyä hoitohuoneessa.

Kaikkia meitä kurssille kokoontuneita T-Scanin käyttäjiä, tai tulevia käyttäjiä innostaa ja yhdistää tietoisuus uudesta harppauksesta, digitaalisesta vallankumouksesta, joka on tapahtumassa hammaslääketieteessä. Meneillään on paradigman muutos tieteissä, jotka tutkivat okkluusiota ja suun sulkemista. Me kurssin osallistujat tunsimme olevamme uuden aikakauden lipunkantajia. Montako kertaa tieteen historiassa on tapahtunut, että kehittyvä teknologia kertaheitolla muuttaa tiedeyhteisön tavan ymmärtää luontoa. Aivan niin kuin muutama vuosisata sitten ryhmä itselleen rehellisiä tieteilijöitä päätti hylätä siihenastisen näkemyksen, että maailma olisi litteä pannukakku, koska saatavilla oli kehittyneempiä kaukoputkia, ajanmittausvälineitä ja muita tähtitieteen harrastajien työkaluja. Teknologian kehitys muuttaa vanhat ajatusrakennelmat kelvottomiksi.

Vielä ei digitaalista purentavoimien mittaustekniikkaa ole propagoitu laajojen työtätekevien hammaslääkärijoukkojen keskuuteen. Erikoinen asenne, suorastaan poliittinen vastarintaliike näyttää vallitsevan yliopistoihin etabloituneissa tiedeyhteisöissä. Lähes kolmen vuosikymmenen vertaisarvioitu tutkimustieto digitaalisten parametrien käytöstä purentaongelmien hoidossa loistaa edelleen poissaolollaan. Purentavaivojen hoidon konsensusraporteissa ja hoito-ohjeissa ei mainita sanallakaan digitaalitekniikkaa.

Meidän kurssillamme, sen sijaan, vallitsi innostus. Meillä on uudenlainen näkemys hampaiden merkityksestä sensoreina, jotka ohjaavat purentalihasten toimintaa. Haluamme levittää tätä ajatusta, koska uskomme, että TMD-ongelmien hoidossa se toimii paremmin kuin vanha, ei-digitaalinen purentafysiologian paradigma.

Henkilökohtaisesti minulla on ollut Tscan-laite käytössäni kaksi vuotta ja minulle oli tärkeää seurata Robert Kersteinin työskentelyä. Robert, oppimestari, selosti ottamansa digitaaliset Tscan-käyrät ja korjasi potilaiden purennat live-potilailla. Hoidon keskeinen toimenpide on ICAGD (Immediate Complete Anterior Guidance Developement Coronoplasty). Toimenpiteen tavoitteena on muuttaa potilaan okkluusiota siten, että kun alaleuan sivuliike alkaa keskipurennasta, kuten tapahtuu silloin, kun teemme lateraalisen sivuliikkeen testiä potilaille, irtoaa sivualueen purentakontaktit toisistaan mahdollisimman nopeasti. ICAGD toimenpide tavallisesti edellyttää kulmahampaiden uudelleen muotoilua, sekä molaari- ja premolaarialueen laterotruusiointerferenssien hiomista.

Oli helpotus huomata, että tekniikka, jota itsekseni olin harjoitellut yrityksen ja erehdyksen kautta, ei ollut ollut ihan pielessä. Hammaslääkärille on harvinaista herkkua saada seurata kollegan työskentelyä vierestä. Hammaslääkärin käsityössä on valtava määrä pieniä detaljeja, joiden oppiminen on tullut kuin huomaamatta tuhansien ja taas tuhansien työvaiheen toistojen myötä. Toisto on oppien äiti. Mikä on vasta-alkajalle parempaa oppia kuin seurata kokenutta mestaria työssään. Ja sitten toistaa työvaiheet kymmenisentuhatta kertaa itse.

Robert käytti runsaasti aikaa selostaen Tscan-käyrien löydöksiä. Digitaalisen informaation tulkitseminen on haaste. Yhdessä Tscan-käyrässä on miljoonia bittejä dataa. Mikä niistä biteistä on kliinisesti merkittävä? Tämänkin taidon voi oppia kokemuksen, yrityksen ja erehdyksen kautta, mutta nyt – kerrankin saatoin kysyä Robertilta!

Tammikuinen iltapäivä Helsingissä hämärtyy varhain. Purennan visionäärien lämmin ja toverillinen kokous Albin-klinikan suojissa jatkui. Keskustelu kävi vuolaana. Olimme syvästi tietoisia suuresta muutoksesta, ei ainoastaan hammaslääketieteessä, vaan koko meitä ympäröivässä maailmassamme. Poikkeuksellisen lämmin sää, pahaenteisenä jatkuva tihkusade huuhtoi Albinin ulkoikkunoiden katunäkymää muistuttaen meitä globaaleista sääolosuhteiden muutoksista. Tieteestä puhuimme myös. Viime päivien poliittisten tapahtumien  sosiaaliseen mediaan lanseeraama meemi ”the alternate facts” oli suosittu iskusana yhdessä, jos toisessa hilpeässä repliikissä päivän mittaan.

Viihtyisän pesämme ympärillä oli koleassa maailmassa meneillään historiallisia, jopa pelottavia tapahtumia. Näitä tammikuun lopun päiviä tultaneen muistamaan historiankirjoituksissa. Tapahtumien pyörre, joka oli saanut alkunsa Washington D.C.:ssä päiviä aiemmin tullaan varmasti muistamaan vielä sukupolvia meidän jälkeemme. Maailmanjärjestyksen muutos salpaa hengityksen. Auttamatta mieleeni tulee kuuluisa reportaasi, jonka John Reed kirjoitti sata vuotta sitten. Hän kirjoitti historiikin lokakuun vallankumouksen tapahtumista Pietarissa ja nimesi teoksensa ”Kymmenen päivää jotka järisyttivät maailmaa”. Tänään, niin uskon, elämme niitä meidän vuosisatamme kymmentä päivää, jotka maailma tulee muistamaan järisyttävinä.

Tiedemaailmassa merkittäviä muutoksia voidaan pitää vallankumouksellisina, mutta muutoksen vauhti useimmiten ei päätä pyörrytä. Akateemiselle etablemangille on luonteenomaista pitää aina parempana nollaversiota mistä tahansa ideasta, jota on ryhdytty hypotetisoimaan. Olen taipuvainen uskomaan, että nollittelu hypoteesipreferoinnissa on heille eräänlainen ylpeilyn aihe, jos saan luvan sanoa.

Kauanko kestänee, ennen kuin digitaalinen okkluusiovoimien mittailu on yleisesti suositeltu menetelmä TMD-potilaiden diagnosoinnissa ja hoidossa, mutta idean alkuperäinen vallankumous kävi hyvin nopeasti. Olin utelias tietämään, mistä Robert sai idean, että sivullepäin laterotruusioon liukuvan alaleuan tulisi liukua kulmahampaiden, ei molaarien eikä premolaarien varassa.

Robert kertoi:

”Se tapahtui vuonna 1987. Olin tuolloin tekemässä väitöskirjaani Tscanin ensimmäisillä versioilla. Iltaisin tein kliinistä potilastyötä. Olin tekemässä purennan hiontaa sillä tyylillä niin kuin niitä siihen aikaan tehtiin TMD-potilaille. En ollut vielä saanut purentaa valmiiksi, kun puhelin soi ja minun oli mentävä toiseen huoneeseen puhumaan. Puhelu kesti kymmenen minuuttia. Kun palasin hoitohuoneeseen oli potilaani ihmeissään. Hän sanoi, että viimeiset kymmenen minuuttia on hänen purentansa ollut rennompi ja mukavampi kuin koskaan. Oli jo myöhä ja arvelin, että jos kerran potilas on tyytyväinen, voisin viimeistellä purennan hiuonnan muutaman päivän kuluttua toisella käynnillä.

Sama rouva tuli taas vastaanotolleni joku päivä myöhemmin ja hän oli edelleen tyytyväinen uuteen purentaansa. Olin heti aavistanut, että olin toimenpiteelläni saanut aikaan jotain, mistä ammattikunnallamme  ei ole aikaisempaa tietoa. Pyysin saada tehdä rouvalle Tscan-tutkimuksen, jossa sitten huomasin, että hänen kulmahampaiden varassa tapahtuva sivuliikkeensä sujui huomattavasti nopeammin kuin sivuliike yleensä sujuu ryhmäkontaktien varassa…”

Tämä havainto johti tutkimussuunnitelmaan ja artikkeliin, joka julkaistiin Journal of Prosthetic Dentistry -lehdessä. Robert Kerstein on sittemmin kirjoittanut purennan dynamiikasta yli neljäkymmentä artikkelia vertaisarvioituihin lehtiin. Mielestäni Robert Kersteinin työ on kumouksellista hammaslääketieteessä. Okkluusiovoimien dynamiikkaa koskevia tutkimuksia ei pitäisi enää pitää validina ellei aineistoa ole todennettu tietokoneavusteisilla järjestelmillä.

Filosofi Platonin mielestä ideat pyörittävät materialistista maailmaa. Uudet ideat voivat olla tervetulleita toisille, kun taas jotkut kokevat uusien ideoiden tuomat muutokset pelottavina. Niin tai näin, kun uusi idea on päässyt valloilleen Pandoran poksista, ei sitä enää voi maahan polkea.

Toisinaan uuden idean karkuun pääsy vaatii vain kymmenen minuuttia, ja maailma järkkyy…

The ten minutes that shook the world

I just returned from Helsinki. I was attending to a hands-on course.

I am utterly grateful to dr. Robert Kerstein, who had once again endured the inconveniences of trans-Atlantic flights and the fog and gloominess of our mid-winter sub-arctic darkness. The course-attendants, however, were well protected from the harsh weather and the inconvenient realities of the world that surrounds us. Revolutionary enthusiasm prevailed around the coffee-brewer in the cozy and smart lobby of the clinic “Albin” – a private practice owned by a digital-occlusion-minded dentist-couple Satu and Kai. The patient waiting room served as an improvised lecture hall. An open door and a video connection into the operatory room showed Robert Kerstein demonstrating his work with live patients. We were a small group of Tscan users and would-be users, all aware and united with great expectations of a huge leap, a revolution that is actually happening in dentistry. A change of paradigm is underway in the sciences of occlusion and jaw-closing, anyone can see it. We, the attendants of this study-club, we felt we were the standard-bearers of a new age to come. How many times it has happened in the history of science that a new invention completely changes the way the scientist think. It is like a few centuries ago, when majority of honest-minded scientist rejected the idea of our world being flat, because of the advent of telescopes, more accurate time-measuring devices, and other new tools for astronomy studies. Technology makes the old views obsolete.

As yet of today, the digital processing of data from occlusion forces, has not yet been propagated to the hordes of wet-finger, working-class dentists. Furthermore, there is a curious attitude, almost a political resistance movement among the established scientific community not to pay attention to the data presented in Tscan studies since almost three decades. Instead, the mainstream of the established authorities in the field of TMJ-diseases elaborate consensus papers and protocols for diagnosis and treatment, where the digital occlusal force measuring is not even mentioned.

Our study-club comprised of practicing dentists, young and more seasoned ones, and a hygienist, all devoted to understanding the fundamental role of the teeth as the sensory organ that guides the muscles of mastication. We all shared the need to promulgate the new way of thinking for the wellbeing of TMD patients all over. All of us were convinced that the proper use of modern digital technology will help our patients better than the treatment protocols offered by the non-digital-old-school-establishment.

Personally, with my only two years of experience with Tscan in my practice, I loved to see Robert, the old master, explain the diagnosis and perform the ICAGD procedure. The essential of this procedure is to change the way teeth occlude in such a way, that as the lateral movement from the maximum intercuspation begins, as we do the lateral excursion test, the shape of the upper and lower canine teeth immediately deflect the laterally moving mandible so that the back teeth disclude in shortest possible time. The ICAGD procedure involves possibly reshaping of the canine tooth and practically always the grinding down of small amounts of tooth enamel from the molar and premolar region.

I was relieved to find out that the clinical conduct I had been learning by myself by trial and error in my own practice, was not so bad. It is a rare occasion that a dentist sees his/her colleagues do their work. In the art of dentistry there are so much details in the procedures that can only be learnt by trial and error and by repetition of each step thousands of times. Repetition is the mother of learning. For a novice there can’t be better thing to do than to first carefully observe a skilled master do the job. And then do the repetition oneself ten thousand times over.

Robert meticulously discussed the Tscans he took from the live patients. Interpretation of events proceeding in a Tscan is always a challenge to your intellect. There are millions of bits of data in a single scan, which bits are of clinical importance? Here again, repetition helps, but now for once – I could ask Robert!

Helsinki January afternoons turn to dusk early. The warm and comradely union of visionaries of occlusion continued at the premises of Albin Dental Clinic. Discussions were flowing freely. We all shared the awareness of historical changes happening not only in dentistry. The exceptionally warm weather, gloomy drizzle of rain was an ominous sign of the global change of weather conditions. Talking of science, the newly introduced meme “the alternate facts” was not uncommonly used punch line in our discussions. I am writing this article only ten days since the inauguration of president Trump.

The world outside of our cozy den was undergoing historical, even frightful events. These are the days that will be remembered in history writing. The whirl of events that had started days earlier in Washington D.C. will surely be remembered by generations after us. The pace of the world order changing is breath-taking.  I can’t help but comparing these days to the famous writing by journalist John Reed. He reported the historical events in the city of St. Petersburg one hundred years ago and titled it “Ten days that shook the world”. Today, we really are living the ten days of our century that will be remembered to have shaken the world.

In the world of science, however, the significant events may be described as revolutions, but the pace of change is less daunting. Of nature, the academic ranks prefer the null of any new idea hypothesised. I tend to believe the nullishness of hypothese-preferring is a sort of pride for them, if I may say.

Whatever will be the course of time needed for the general acceptance of digital occlusion force scanning in the diagnosis of TMD patients, the fundamental revolution occurred very rapidly. I was curious to know, how did Robert come to the idea that the deflection of the laterally moving mandible should be caused by the canine teeth, not the back teeth. When did this idea strike to him?

Robert related:

“It happened 1987. By the time I was in my academic studies with the first versions of the Tscans. In the evenings I used to do clinical work, that consisted of treating patients with TMD problems. It was late in the evening and I was in the middle of doing bite-adjustment of the type that we used to give our patients in those times. I had not finished my patient yet as the telephone rang and I had to leave the patient to answer the phone in the other room. The telephone call lasted ten minutes.

As I returned to the operatory room, my patient was amazed. She asked me what had I done, since now for ten minutes her bite had never felt more relaxed and easy. It was kind of late and I thought there probably would not be any problem not to finish her bite that night –  I would finish adjusting her bite a few days later.

To my astonishment when she arrived the next time she was still very happy with her bite. I immediately realized that there was something unknown to our profession in what I did to that lady. So I took her to the early Tscan test and there I realized that the canine-guided lateral excursion proceeded so much faster compared to what happens with a group function…”

This finding proceeded to a study plan and the publishing of the study in the Journal of Prosthetic Dentistry. Since that Robert Kerstein has written dozens of articles on occlusion dynamics. In my opinion the scientific work of Robert Kerstein should be regarded a revolution in dentistry. Any new research on dynamics of occlusion can’t be regarded valid unless the data is proven with digital measuring.

Plato, the philosopher said, it is the ideas that run the material world. New ideas may be welcome for some, for others the changes brought by new ideas may be frightening. However, once an idea has been let out of the Pandora’s box it can never be ignored again.

Sometimes, it only takes ten minutes to shake the world irreversibly.

Kuukkeli, erämaiden tietäjä

kuukkeli

Terve, sinä tiedon etsijä!

Olet samoillut internetin äärettömiä erämaita etsien tiedon kultaa. Sinulla on kysymyksiä purentavaivasta, vihlovasta hampaasta, tai sitten sinua vaivaa hampaiden narskuttelu öisin. Minun blogini on kuin heikko virvatuli jäätyneellä tundralla – se ei ole bittiavaruuden kirkkaimpia soihtuja. Olit etsinyt hakemaasi jo kauan, ehkä olit jo menettänyt uskosi mitään löytäväsi, mutta kuitenkin vielä heikko toivo kajasti tietokoneen näytöllä… Kuukkeli kuulosteli hakusanojasi, keikutteli pyrstöään, hypähti kuusen oksalle ja neuvoi ehkä neljännellä hakutulossivullaan sinua:

– ”Mene pois tiedon valtaväyliltä. Hae blogbites.net… Iske hakkusi ja lapiosi blogbites.net -kultasuoneen. Sieltä löydät ennen kuulumattomia salaisuuksia koskien purentaelimen toimintaa…”

Tämänkertainen blogini ei vielä kerro, kuinka bruxismi, hampaiden narskuttelu parannetaan, mutta ehkäpä ensi vuonna omistan sille artikkelin. Menneen vuoden artikkeleissa olen selostanut, kuinka saadaan purentalihakset rentoutumaan, leukanivelen napsuminen paranemaan, hampaiden vihlominen loppumaan. Kannattaa uskoa Kuukkelia. Monesti tietäjälintu Kuukkelin kanssa käy myös niin, että kun yhtä etsii, toisen löytää. Tämä artikkeli on tarkoitettu vuoden viimeiseksi, loppukevennykseksi blogbites.net -blogin ensimmäiselle vuodelle. Tervetuloa jatkossakin viihdyttävien, mutta tiukan tieteellisten artikkelieni pariin. Kiitän lukijoitani mielenkiinnosta ja tarjoan tällä kertaa junamatkaa mielikuvitusmaailmaan.

Tämänkertainen artikkelini on uudelleenjulkaisu. Turun hammaslääketieteen kandidaattiseuran Puukiila -lehti julkaisi seuraavan tarinan 80-luvun alkupuolella. Tuohon aikaan purentafysiologia ei vielä ollut päällimmäinen intohimoni kohde. Sen sijaan hampaiden poistot – ja poistojen harjoittelumahdollisuuden vähäisyys askarrutti mieltäni. Tietysti kaikki mikä mieltäni askarrutti, piti saada paperille helposti luettavaan muotoon ja miellyttämään lukijaa. Seuraavan tarinan myötä toivotan lukijoilleni rauhaisaa loppuvuotta.

Tervetuloa pohjoisiin erämaihin. Pehmeät oljet härkävaunun lattialla kutsuvat, juna jo viheltää, talvinen seikkailu alkaa…

 

Hommissa Holodnoissa

Akademogradin hammaslääketieteen laitoksen kirurgian poliklinikalla olivat asiat huonossa jamassa. Laitoksen johtaja mittaili huolestuneena työhuoneensa lattiaa. Kuinka hammaslääketieteen opiskelijakandidaatit voisivat koskaan oppia ekstraktioita, eli poistamaan hampaita, kun heille ei riitä potilaita? Olisi lyhytnäköistä päästää kandidaatteja työelämään ilman riittävää poistokokemusta. Mikä nyt neuvoksi?

Syksyinen tuulenviima keräsi vauhtia Akademogradin leveiltä bulevardeilta ja tuiversi pyörremyrskynä jo lakaistut vaahteranlehtikasat vasten professorin työhuoneen ikkunaa. ”Ahaa” professori äkkiä oivalsi. ”Soitanpa ystävälleni Posionmaan Pietarille, häneltä ehkä löytyy vastaus ongelmiimme.”

Mitähän laitoksen johtaja oli keksinyt?

Meille kandidaateille asia selvisi muutaman viikon kuluttua. Ilmoitustaululle tuli lista, johon sai merkitä nimensä. Siinä luki:

”Kirurgian osasto, kliininen palvelu. Työkurssille on varattava henkilökohtaiset tarpeet sekä hammasharja ja makuupussi. Kurssin kesto on kolme viikkoa, jonka aikana perehdytään hampaanpoistoon, olosuhteiden pakosta, Posionmaan kuvernementin eri terveyskeskuksissa”

Me kandidaatit olimme tietysti hieman yllättyneitä, mutta ymmärsimme kyllä, että Akademogradista ei poistopisteitä tulisi herumaan, ja että ainut keino saada oppia oli siirtyminen vihreämmille laitumille. Olimme kuulleet huhuja, että joissakin Posionmaan kuvernementtien terveyskeskuksissa ei paljon muuta työtä hammaslääkäreille ollutkaan kuin hampaanpoistot aamusta iltaan. Sitä paitsi, ainakin minulle, siirtyminen kolmeksi viikoksi pois Akademogradin urbaaneista ympyröistä pohjoisten metsien raikkauteen tekisi hyvää kiusatulle maksalleni. Kirjoitin siis empimättä nimeni listaan.

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Pari viikkoa myöhemmin olimme kokoontuneet keskusrautatieasemalle nyytteinemme. Talvi oli tulossa lenseään opiskelukaupunkiimmekin ja me hytisimme vilusta laitoksen johtajan pitäessä meille asemalaiturilla läksiäispuhetta. Professori kehotti meitä käyttämään palvelusaikamme mahdollisimman hyödyllisesti ja terveellisesti – minua alkoi melkein hävettää, että olin tullut sulloneeksi henkilökohtaisten tavaroitteni joukkoon pari, kolme votkapulloa.

Juna vihelsi ja me, odontologian pioneerit hyppäsimme malttamattomina härkävaunuihin, joissa tulisimme matkustamaan mantereen poikki. Tunsin pian huojennusta, kun huomasin, että myös monet muut opiskelutoverini olivat ottaneet väkijuomia matkaevääksi. Juna kolkutteli rytmikkäästi eteenpäin ja iloiset kandidaatit kajauttivat välillä reippaan laulun, välillä joku kertoi kaskun, jolle naurettiin remakasti. Kamiina tuhisi kodikkaasti härkävaunun nurkassa ja sen päällä porisi vanha, mustunut kahvipannu, täynnänsä totivettä.

Matka oli pitkä, mutta se sujui rattoisasti. Seuraavana aamuna saimme aamiaista Bogrovian asemaravintolasta laitoksemme johtajan kirjoittamalla määräyksellä. Reino ja Ville ottivat oluet jo aamutuimaan, aika velikultia. Tarinoitsimme kaminan ympärillä junan jyskytellessä halki äärettömien tasankojen. Välillä urheilimme siirtymällä vauhdissa vaunuliittimiä pitkin tyttöjen vaunuun, he ihailivat rohkeuttamme. Tytöt paistoivat kaminan kannella mainioita lettuja, me pojat pilkoimme tytöille polttopuita. Illansuussa aloimme jo vilkuilla ulos. Posionmaan jylhät erämaat ja salskeat kuusimetsät avautuivat vuoristoiselta radalta mahtavina panoraamoina.

Varhain seuraavana aamuna heräsimme junan pysähtyessä nytkähtäen.

”Nordburg, pääteasema!”, kiljui konduktööri. Kömmimme ylös makuupusseistamme tukka koppurassa, ilta oli ollut tosi riehakas. Vaunumme ovi vedettiin auki ja oviaukkoon ilmestyivät pyöreät, hymyilevät miehen kasvot.

”Tervetuloa Posionmaahan. Minä olen kuvernementin ylihammaslääkäri, sanovat minua Posionmaan Pietariksi” sanoi nauravasilmäinen ukkeli. ”Pitäkäähän hoppua, pääsette tästä kuorma-autoilla terveyskeskuksiinne”.

Meidät jaettiin kolmeen ryhmään, jotka lähdimme, kukin omille tahoilleen armeijan vihreissä kuorma-autoissa. Pakkasta tuntui olevan aika mojovasti ja saimme automatkan aikana kaivella villapuseroita repuistamme. Meidän automme ajoi viidentoista penikulman päässä sijaitsevaan Holodnoin seudun terveyskeskukseen.

Holodnoin seudun terveyskeskus vastasi yli 200 000 asukkaan hammashuollosta. Väestö koostui enimmäkseen kalastajista, metsästäjistä ja nomadeista. Paikallisiin tapoihin ei kuulunut tulla hammaslääkäriin ennen kuin tuskat kävivät sietämättömiksi, varsinkin nomadit pitivät hammaslääkärissä käyntiä nöyryytyksenä. Ymmärtää siis hyvin, että Holodnoi oli oikea ekstraktioiden eldorado.

Majoituimme lautaparakkeihin. Vastaava hammaslääkäri tarjosi meille tulopäivän iltana kotonaan muhkean poronkäristysillallisen. Joimme runsaasti olutta, tosin Posionmaan kuvernementin hallitus on rajoituksin kieltänyt täysvahvan oluen myynnin. Eipä silti, hauskaa meillä oli. Tutustuimme paikallisiin asukkaisiin vieraillessamme illallisen päälle kylän ainoassa kievarissa ja kutsuimme heitä jatkamaan juhlia lautaparakkiimme. Villen hanuri soi aina varhaisille aamutunneille saakka. Välillä käytiin tuulettumassa parakin portailla. Pohjoisten, talvisten metsien pitkä ja sininen yö teki minuun voimakkaan vaikutuksen.

Seuraavana aamuna meidät herätetiin hellävaroen silliaamiaiselle. Pian sen jälkeen saimmekin jo ottaa vastaan potilaita. Iltapäivään mennessä olin saanut jo kaksitoista pistettä kokoon. Pitkiä, nautinnollisia väsytystaisteluja käyrien ja vastahakoisten kulmureiden kanssa, nyppäyksenomaisia alaetuhampaita ja yläviisaudenhampaita – tunsin todella nauttivani.

Päivät alkoivat sujua työn merkeissä vauhdikkaasti. Meille kullekin kandidaatille jaettiin aamulla päivän tehtävälista. Tavallisesti viitisentoista ekstraktiota. Lounaan söimme terveyskeskuksen ruokalassa, illallisen saimme ottaa mukaamme pakattuna valmiiksi. Tutustuimme paikallisiin erikoisherkkuihin, kuten hylkeenmuniin ja riekkokeittoon. Oli aivan tavallista, että ruokalassa tarjottiin lounaaksi runsas annos hyvää, punaista lohta. Akademogradissa tuollaiset herkut olisivat maksaneet omaisuuksia, mutta Holodnoissa, minulle kerrottiin, työehtosopimuksissa nimenomaan sanotaan, että lohta saa tarjota työntekijöille korkeintaan kolmena päivänä viikossa. Niin tavallista on lohen syönti pohjoisessa.

Iltaisin saavuimme parakeille tavallisesti kuuden, seitsemän aikaan. Mikään televisiokanava ei näkynyt Holodnoissa, mikä oikeastaan oli meidän kannalta hyvä, näin meidän oli pakko keksiä itse ohjelmaa iltojemme iloksi.

Kuka kirjoitti kirjeitä kotiin, taikka mielitietylleen. Toiset taas pelasivat raminaa tai koiraa. Voitimme terveyskeskuksen kantahenkilökunnan hiihtoviestissä lähinnä Reinon loisteliaan ankkuriosuuden turvin. Kyläläiset suhtautuivat meihin ystävällisesti ja välittömästi. Alkoholiliikkeen omistaja tuli itse avaamaan meille ulko-oven lähtiessämme hänen kaupastaan raskaine kantamuksinemme. Mirjami kerkesi iltapuhteinaan kutoa Holodnoin kotitalouskeskuksessa itselleen värikkään raanun. Reinon ja kylänvanhimman kauniin tyttären välille virisi jopa pieni romanssi.

Mutta kolme viikkoa kului nopeasti ja eräänä iltana huomasimme suruksemme viettävämme viimeistä iltaamme Holodnoissa. Aatokset palasivat pitkästä aikaa arkisiin opiskeluhuoliin. Joku yritti keventää tunnelmaa: ”Mahtavaa päästä täältä korvesta takaisin sivistyksen pariin”, mutta huomasi pian itsekin, kuinka typerästi se oli sanottu. Ville soitti surumielisesti hanuria ja me siemailimme höyryävää teetämme vaitonaisina. Holodnoin seudun mahtava luonto oli ikään kuin jäähyväisiksi hiljentynyt tyyneksi pakkaseksi ja majesteetillinen täysikuu loi hohtoaan sinisille hangille.

Lopulta joku meistä kristallisoi harhailevat, murheelliset ajatuksemme sanoiksi: ”Kunpa ihminen voisi elää näin, opiskella näin, ilman stressejä, nauttia elämästä, ja myös opiskelusta, kunpa tällainen olisi mahdollista myös Akademogradissa.”

Voisiko sen selvemmin sanoa?

Filibustering in the House of Parliament of Occlusion

Within any system, the forces of opposition cause strain and tug-of-war. For the common good, a settlement must be negotiated between the parties of opposing forces. A fundamental law of conduct is required so that the discords between different parties can be settled in an economic and civilized manner. Sometimes, lengthy skirmishes between parties with opposing goals can’t be avoided. Leadership by a diligent outsider, a presidential entity skillful in politics, can help to maintain the unity of system.

The blogbites.net is a blog about bites, and I’m talking about mastication, of course.

Performing an equilibration of an unbalanced bite with repeated Tscan-measurements is a sort of political science of sensory organs of occlusion. I fancy, the occlusion system is analogous to a kind of a house of parliament with a two party political system. There can be up to 32 members of parliament and each of these represent their own district of sensory organs. The sensors of the teeth involved send votes to the polling station, the ganglions and nuclei of the trigeminal nerve. As of yet, we only know that the afferents from a molar tooth periodontal ligament propagates directly, without synapsing, to the trigeminal motor ganglion. Maybe, the afferent pathways of the anterior teeth take a different route. However, what I see in a Tscan movie, I interpret, there are two different kinds of political interest-groups of teeth. The occlusal forces act as the votes do in a parliament sitting.  The House of Parliament of Occlusion reacts very rapidly to the challenges of environment. A piece of seasonal delicacy, fruit and nut cake, is placed between the molars. A microsecond later, a parliamentary committee has made a decision to unleash the temporalis and masseter muscles. The mandible starts it upward movement. The soft dough part of the bolus between the molars is quickly squeezed, but suddenly, a piece of nut hits the occluding molar surfaces. A quick reappraisal of the situation is needed. The Back Tooth Working Class Party (BWCP, in short) – is adamant, the muscles should go on biting hard, or even harder. The members the Anterior Guidance Coalition (AGCP) can only watch by as the working class of the back teeth get all the votes and support from the sensor organs of their district.

However, nothing is constant in politics. The dental arch of the up-surging mandible hits the maxillary dental arch. The collision forces are partly absorbed by the food bolus, but a definite sharp contact is felt with the sensors of canine teeth of the working side. These unyielding, bold figures of the AGCP provide more sensory input, votes, than the back teeth do. The back teeth are not yet in actual tooth-to-tooth contact, but just wrapped in a sticky mass of fruit and nut cake. The results of the vote are unambiguous. According to the Universal Law of Jaw-closing the BWCP must restrain in its demands of masseter and temporalis activity. An agreement is made to slow down the mandible by the overwhelming majority of votes coming from the AGCP districts.

A microsecond later the masseter and temporalis muscles are ordered to rest, whereas the median pterygoid muscle starts pulling the mandible towards the maximum intercuspal position (MIP). This process, the mediotrusion, does not necessarily proceed smoothly. A piece of nut may get caught in a fossa of the opposing laterally gliding occlusal tooth surfaces. The emotions are heated in the district of BWCP. The piece of nut deflects slightly the path of the gliding mandible. In turn, the canine-canine contact is disengaged. Loss of votes for the AGCP ensues, and parliamentary orders execute, once again, the masseter and temporalis back to work. The piece of nut, that was stuck in a fossa, gets disintegrated. The canines make contact again, and the AGCP is once again triumphant. The glide of the mandible towards the MIP can continue.

There are situations where the parliamentary occlusal democracy is not working efficiently. The muscles can’t move the mandible. Sometimes when I test my patient’s ability to do the lateral excursion, the patient finds it impossible. The patient can’t do the lateral glide. The patient just makes tremendous efforts with his/her neck muscles bulging, nothing else happens except that after a while the patient sighs and admits that there must be something wrong with the brains…

There’s nothing wrong with the brains, nor with the brain stem nor with the ganglions of the trigeminal nerve. The nerves are working just right. There is a political crisis going on in the House of Parliament of Occlusion. Erosive, acidic diet and detrition have disfigured the shape of the mandibular canine. Formerly, in its time of glory, its tip was covered with bright enamel. It was the pinnacle member of the AGCP. The tip of canine has now turned into a flat plane of abraded, brown dentin. If it was only the esthetics! In MIP, the distal surface of the worn-down mandibular canine lies now in contact with the palatal cusp of the upper first premolar, a working class tooth. That means conflict! Believe me, class distinctions between neighboring teeth are sorely felt. A slightest lateral move of mandible would flare up traditional BWCP sentiments and make the masseter and temporalis go. The disfigured and humbled canine tooth tries in vain to disengage the masses of back tooth working class contacts. Conflicting parties refuse to work together, Instead, they orate their arguments in endless speeches. The movement of the jaw is stalled because both the parties are filibustering each their own causes. The arguments between BWCP and AGCP have paralyzed the House of Parliament of Occlusion.

Presidential interference is needed. A skilled dentist is an outsider, that is respected by both the parties of the Parliament of Occlusion. Here’s a tip for any dentist to identify this kind of crisis.

If your patient is unable to glide his/her jaw laterally, just place a blade of a hand instrument of matching thickness, it can be an amalgam carver, or as in the video below, the tips of pincers lying on the palatal aspect of the upper canine of the patient, teeth closed. The mandibular canine should be facing the other side of the instrument blade.

The laterally oriented force is now subjected only to the upper and lower canines. The instrument blade-mediated contact disengages the lateral force that otherwise would have been subjected to the palatal cusp of the upper first premolar. Miraculously, with the aid of an instrument blade held firmly between the canines the muscles are enabled to work effortlessly, the lateral excursion is restored. Your patient will be surprised to find out that you have cured his/her brain damage.

A dentist can stop the filibustering between the canine and first premolar by adding composite to the right places of the worn-down canine tooth. A dentist can be the president, that understands the core of the conflicts that are underway in the parliament of a patient’s occlusion. A president has the power to ascertain the stability of the democracy of occlusal forces.

Soundbites of sound bites

This article is about the click and clatter of teeth.

There was a time in my professional career, that I tried to assess the condition of the bite of my patients by listening to the sound of maxillary and mandibular teeth occluding. At those times, I had the habit to grab the jaw of my patients at my hands and carefully guide my patients to close their jaw “right”. Sometimes I could feel with my hands the uninterrupted relaxed jaw movement and the sharp click-sound produced by simultaneous contact of the maxillary teeth opposing with the teeth of the mandible. I often wondered – that can’t be bad. On the other hand, I very often realized that the muscles of my patients were tense and did not allow relaxed closing. A dull, crash-landing noise is characteristic for the unrelaxed and tense bites. Normally, these patients did not complain so much, they seemed to be happy with their bites. Yes, they had the habit of biting a little bit more to the more comfortable side of dentition, but they could live with it. I sometimes tried to change the way they bite. I reasoned that there must be premature occlusal contacts that prevent them from closing their jaw in a relaxed manner. To my dismay, it was very difficult to decide, where in the dentition of my patients the problematic occlusal prematurities happened. However carefully I tried to guide the closing path of the mandible, the ink from the occlusal foil did not always reliably mark the prematurities of occlusion in repeated measurements.

In my previous articles I have presented a hypothesis, the “Philosophiae Naturalis Principia Masticatoria”. It is a novel approach to explain the function of the masticatory system. In my thinking, the afferent information from occlusal contacts from different teeth are guiding different groups of masticatory muscles. The front teeth are inducing an opening reflex, whereas the premolar and molar teeth induce a closing reflex by triggering activity of masseter and temporalis muscles. When the front teeth feel pressure different things happen with the muscles as compared to when most of the occlusion contact point force pressure is felt by the back teeth. I intend to demonstrate my point by making you listen carefully to the sounds of bites.

Don’t I love to hear the perfect click-sound when the patient bites with a perfectly equilibrated dentition. The undisturbed, relaxed closing of the jaws brings simultaneously all the contact points together between the upper and lower jaw. It is a soundbite that makes the clinician dentist immediately  feel rewarded. The filling he/she just made, fits perfectly.

The click-sound – is it a hallmark of quality of occlusion?

How many times did you hear the happy clatter of your patient’s teeth, but nevertheless, the same patient came to you six months later with a fractured cusp of a molar tooth. Should I rely on the sound of occlusion only, or is there something else I should know about the jaw-closing business?

Normally in my office, when I ask a person to open and close his/hers jaws, he/she closes the jaw with a vertical down-up movement. Unlike when chewing a piece of food, there is no lateral excursion of the mandible. Ideally, the closing path of the mandible follows an uninterrupted arch form, at the end point of which all the teeth occlude simultaneously.

rajattu-envelope-of-motionmodified from www.pocketdentistry.com

You can test the sound of your own bite. Should you happen to be one of the fortunate ones that can make a click sound with your jaw-closing, then try tilting your head a little to the left or right, you’ll probably hear the sound of your bite changing – the gravity pulls your mandible out of the maximum intercuspal position (MIP).

The Tscan is a tool to investigate the sequence of events that happen when the mandibular teeth occlude with the teeth of maxilla. The force/time graph, which is shown below the 2- and 3-D occlusal charts in a Tscan movie, indicates the first occlusal contact with a mark “A”. Mark “B” appears when all the points of occlusal contacts have been met.The video shows the points of occlusal contacts accumulating from the earliest initial contact in point A, and followed little past point B.

The A to B part of the Force/time graph is an important parameter. It is a tool of what the previous generations of dentists and occlusion -scientists could only dream of. A long time elapsing between the time points A to B is indicative of prematurities of occlusion. The “normal and physiologic” closing time from the earliest first tooth contact to the MIP is generally agreed to vary between 0,1-0,2 seconds. Would there be a premature occluding contact, we can assume that the closing path of the mandible should have to be altered. Adjustment would take more time. It would take miniature zig-zag-movements and muscle work for the mandible to find its way to the MIP. A microsecond after the first tooth contact a second contact would follow, after a few microseconds later a third one, and up to the umpteenth tooth-to-tooth contacts before the mandible would lay securely in MIP. There can’t be a click sound there, it rather sounds like a soft, jumpy crash-landing of the mandible against maxilla. The duration of the time that it takes from the first occlusal contact, to the full amount of all occluding contacts in MIP is directly related to the sound of jaw-closing. The more evenly the occluding points meet, the faster is the closing time, the sharper and louder is the click-sound and the less there is need for muscles to adjust the position of the mandible to match that of the maxilla.

To find out what my patient’s occlusion time is, it would not make sense to assist my patients by guiding their jaw-closing with my hands. For a Tscan user it is obvious that the occlusion is a finely tuned neuro-muscular event and it is our mission to try to understand the dynamics of occlusion undisturbed, in vivo. The repeated Tscan movies reveal to me, where the premature contact points are. The beauty of the Tscan is that I can be assured that I know where the trouble lies in my patient’s dentition. Grinding off a forceful contact point of a tooth, of course, should be kept to minimum. It is always with a heavy heart that I proceed to shorten an elongated cusp tip of an otherwise healthy tooth. I normally run a low-speed flame-shaped red grit diamond at 40 000 rpm. A few gentle sweeps of the surface of enamel (or hopefully of filling material) can’t take more than micrometers off the load-bearing points. I routinely perform the equilibration with repeated Tscan measurements between the grindings. The “Force Outliers” feature of the Tscan software points out which teeth are subject to rapid increase of relative occlusal force during the A to B phase of closing.

On a Tscan movie the distribution of occlusal forces in the dentition can often be severely skewed. The forceful contacts may be totally asymmetric in the different parts of dental arch. However, even the highest force outliers in the molar and premolar area can very often go unnoticed by the patients. The closing time from A to B, however, can be very short despite there are markedly forceful contacts here and there. I often ask the patient does he/she feel that there would be a point in his/her occlusion that feels more forceful than elsewhere. If I get an answer “Yes”, the patient most often points to some tooth in the anterior area. The force outliers in the back teeth do not seem to disturb the patients. The high forces hitting the back teeth do not seem to slow down the occlusion time either.

Then what about the sound of bite? Did I not just earlier say that I love to hear the click of unison? Yes, despite unevenly distributed high forces in the molar and premolar area, the sound of closing can be a sharp and loud click….

Grinding down an obvious spot of excess occlusal force in the back teeth very often goes unnoticed by the patient. In my practice, I have chosen not to start the equilibration with the forceful contacts of the back teeth. Instead, I always start from the anterior contacts. I have found that it is almost always after I have leveled down the forceful contacts of the anterior area, that the patients report any relief of jaw-closing. The leveling down the anterior force outlier contacts is the easiest way to shorten the A to B time. Time after time I have been surprised to find how little it takes of enamel grinding of the anterior teeth to produce the desired relief in occlusion. Shortening of the occlusion time follows, and yes, the initially murky sound of the bite changes into a sharp click. The data from the Tscan movies supports this phenomenon. Leveling down the excessive force outliers of the anterior teeth effectively reduces the occlusion time.

To sum it up, the click-sound of occluding teeth in itself is not necessarily a sign of  healthy occlusion, but the absence of a click is always a sign of tense and slowed-down closing reflex. The sensory organs of the front teeth react to force outliers in microseconds. A very rapid muscle reflex ensues to slow down the momentum of up-surging mandible. In contrast, should the force outlier contact point happen in the premolar and molar region, no such slow-down of mandible happens. This is because the back teeth must produce a qualitatively opposite reaction to force outliers as compared to anterior teeth.

The soundbites of sound bites corroborate the basic tenet of Philosophiae Naturalis Principia Masticatoria. The front teeth are different from the back teeth. To make the dentition occlude with evenly distributed occlusal forces, it takes little more than just listening to the clatter of teeth. A Tscan is indispensable for the work…

Philosophiae Naturalis Principia Masticatoria. Part II

In my previous blog article I analyzed the dynamics of jaw-closing in 6 postulates. The take-home-message of my previous blog article was: The sensory afferent information of pressure-loading in periodontal ligament from anterior teeth produces a completely opposite reaction in the direction of muscle activity as compared to the sensory afferent information of the back teeth.

The postulates 1 to 5 should hopefully have been quite self-evident for anybody with an interest for the dynamics of occlusion. However, I have never seen an article that would sum up the concept, which I presented in my postulate 6.

The sensory afferent information from teeth 1-2-3, from the midline shuts down the activity of the vertically down-up directing masseter-temporalis jaw-closing muscle group of the phase-one of jaw-closing. By means of sensory-motor neural control via the brain-stem, the antagonistic pterygoids-set of muscles on the working side take over, and the movement of the mandible takes a new turn towards the midline. This idea did not come to me just by biting on a piece of apple. For at least two decades it has been my everyday practice to always try to arrange my patient’s dentition in such a way, that the red ink paper that I use to check the lateral excursions, always draws a beautiful straight line on the palatal aspect of upper canines and the buccal aspect of lower canines, respectively. Most often, to change the patient’s bite is not an invasive procedure. Instead of grinding down of tooth enamel, I try to figure out, what would be the ideal form and shape of my patient’s canine teeth to provide an immediate and smooth disclusion of the back teeth in lateral excursions. All it takes a piece of rubber dam and a clamp, a bit of engineering spirit and a little of artistic touch, as I layer out different shades of composite to make beautiful canine teeth. Overwhelming majority of my patients respond positively to this intervention. They normally say that the bite is different, but in a good way, it is more stable. The Tscan movies illustrate the difference after the establishment of canine guidance.

In the first video clip even an uninitiated dentist can see that the bite does not look good. Pay attention to the slight jaggedness of the black total force curve. The staggering line illustrates the tug-of-war between the closing and opening reflexes. In the Tscan movie software, time is divided into sections. “A” marks the first occlusal contact of closing. During the time span from “A” to “B” increasing number of occlusal contacts appear until the maximum, as calculated by the software program. The black total force line normally rises a bit after the maximum number of occlusal contact points is reached. The “B” to “C” part of the graph designates the power-clench that takes place after the teeth are set for maximum intercuspidation. In this movie, I instructed the patient, actually  she is my daughter, to perform an excursion of her mandible to the left. The lateral excursion is happening after time point “C”. That part to the point ”D”, where there is only one single load beearing tooth takes a loooong time…

Keeping in mind the postulates of jaw-closing, it is crucial to understand, that when we examine the lateral excursions of our patients, we actually are examining almost exactly the same path of gliding occlusal contact points, inversed, that take place in the mediotrusive phase-two of jaw-closing. If I just could be able to flip this .mp4 file to run backwards, you would see just about what was happening in my daughter’s mouth every time she was trying to chew gum. Well, she couldn’t chew gum. That would have triggered the migraine. See, how the occlusal force pillars in the molar area suddenly surge up high and red. Imagine the amount of distress, friction and tug-of-war taking place in her occlusal system thousands of times every day. There is a golden advice for any of your patients suffering from TMJ and occlusal instability: “Don’t bite”

Since my daughter refused to obey my advice, I added composite to her canines, but I also had to bevel out some parts of the most off-the-Camper-line cusp tips of her back teeth in the maxilla. Here you can see her perform her left lateral excursion now

Her headaches vanished the very day that the canine guidance was established in her dentition. The first video was a “bad bite” and the second one is a “good bite”. Comparing these two videos gives you some idea what amount of information there is in a Tscan movie. The use of Tscan has reassured me in my almost career-long belief, that the anterior teeth should bear the occlusal load in lateral movements. Except, that now it is no longer matter of believing, the facts are there, on my computer screen.

Seeing the occlusal interferences of laterotrusion developing in a slow-motion movie has greatly improved my ability to find out the trouble spots of my patient’s occlusion. Individual prematurities in the premolar and molar teeth during lateral excursions, are not easy to detect. When examining the lateral excursions of my patients, the red ink marks that are produced by prematurities on the palatal and buccal inclines of the back teeth are often only wispy dots. Only seldom do the interferences of the back teeth appear as continuous lines, quite unlike they do in canine teeth. Before the Tscan it was quite impossible to distinguish the lateral interference foil-marks from the dots marking the occlusal height bearing spots. This used to be my distress. I was discouraged to do permanent enameloplasty if I was in doubt of my foil marks. Nowadays I compare the foil marks with a Tscan-movie. I can see it is a fact, that the appearance of a foil mark, light or strong, actually has no connection to the force that caused it. By following the Tscan movie I can adequately distinguish even the wispiest ink dots and assess their importance for the smoothness of the medial glide of the mandible of my patients.

There is something very frightening in this image.

christopher-lee

The Hammer Films  has provided Christopher Lee with a set of goodish size canine teeth. I am a great admirer of late Christoper Lee’s art, but in this image there is something too terrifying in it. With canines like that I couldn’t imagine of myself punching holes in throats of blonde girls however tender-pearly-white skins they would have. I mean, under the softest alabaster skin, an unexpected collarbone might be lurking. Hitting a collarbone with such canines would immediately result in an opening reflex…I couldn’t bear the shame of the disaster of a terrified victim screaming and running away from my hold…

Regarding myself as a man of science, I rejected the fancies of film industry and turned my interest to the real vampire-bats of nature. How do they cope with the risk of hitting a collarbone of their victim’s? A google-pics search provided me with a following beautifully naturalistic drawing of the skull of a vampire-bat

vishnu-prasad

(For the use of this picture I am most thankful for the artist Vishnu Prasad, for more of his art, please visit https://www.instagram.com/artgeek09/)

Look at those canines. Are they canines? Count the teeth, starting from the midline. The third tooth from the midline doesn’t impress. The big vampire tooth is actually fourth from the midline, the first premolar.

It is the same thing with other beasts of prey. Lions, tigers, wolves. They don’t ruminate. They use their teeth to catch the leg of an antelope and once they get a grip with their teeth, the grip holdsSuden kallo

Look at that skull of a wolf in the Helsinki Zoological Museum. The big canines are not the front teeth, they actually are the first premolars. That’s the tooth number four from the midline, and that’s how Nature has it planned, for a good reason. Function makes the form. The condyles of dogs and wolves are small, but the masseters can produce huge closing-of-the-jaw forces. The huge first premolar-canine of the beasts of prey provides just the sort of sensory feed that enhances the closing-in activity of the masseter. The price they pay is the lack of lateral movements. Your pet dogs don’t do lateral excursions so much. They cut pieces of their chewing -bone with vertical movements of their mandible. The shape of the dental arches is more like a rectangle, not parabolic. There does not seem to be a phase-two of jaw-closing in dogs. The direction of the jaw-closing remains the same all the way. Would there be a slight laterotrusion in the rudimentary condylar system of dogs, the first tooth-to-tooth contact point would be the dog-canines i.e. the tooth number four, according to the Universal Law of Jaw Closing.

 

The opening reflex that is so vital for us humans to chew our food exists in the dogs also. Dogs don’t like to chew their chewing-bones with their front teeth, they always grab it by the side of their mouth.

In conclusion, the sensory-motor control of the chewing pattern of humans is guided by a system that is common for humans, lions, wolves and probably even the vampire-bats. I have never seen any scientific articles demonstrating qualitative differences in the anatomy of afferent innervation of the front teeth as compared to the back teeth. From my reasoning above, however, one tends to speculate there still is something in the sensory-motor control of occlusion that we have been unaware of. There must be something between the tooth periodontium and brain stem, where the sensory information regarding pressure changes switches over to the opposite, regarding whether the afferent information is coming from the front or back teeth.