importance of occlusion in oral function

8/3/2019 Importance of Occlusion in Oral Function

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The importance ofThe importance of

occlusion in oral functionocclusion in oral functionand dysfunctionand dysfunction

A. De LaatA. De Laat

Copenhagen 2007Copenhagen 2007


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IntroductionIntroduction

Aim of dentistry and orthodontics inAim of dentistry and orthodontics in

particular : maintenance and restoration ofparticular : maintenance and restoration of

masticatory functionmasticatory functionOther goals : speech, esthetics, .Other goals : speech, esthetics, .

? Preventive action concerning? Preventive action concerning

development of dysfunction (and pain)development of dysfunction (and pain)


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OutlineOutline

Dental occlusion and normal jaw function :Dental occlusion and normal jaw function :

-- masticationmastication, forces, forces

-- swallowingswallowing (and(and speech)speech)-- mastication and development ofmastication and development of

occlusionocclusion

(Mal)occlusion and Temporomandibular(Mal)occlusion and Temporomandibular

DisordersDisorders

-- etiological role ?etiological role ?

-- management of TMDmanagement of TMD

-- other orofacial painsother orofacial pains


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MasticationMastication

Lundeen, Gibbs, 1972-1985


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Influence of foodInfluence of food


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Influence of tooth morphologyInfluence of tooth morphology


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Influence of ageInfluence of age


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Influence of jaw relationshipInfluence of jaw relationshipP. Proeschel (1988, 2006)P. Proeschel (1988, 2006)

Different chewing patterns :Different chewing patterns :


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Soft foodSoft food Tough foodTough food


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Angle ClassAngle Class


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Cross biteCross bite


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ConclusionConclusion

Differences between groups with differentDifferences between groups with different

(mal)occlusions or tooth morphology(mal)occlusions or tooth morphology

DO exist..DO exist..

But are they important ?But are they important ?


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Bite forceBite forceM. Bakke (2006)M. Bakke (2006)

Objective measure of one parameterObjective measure of one parameter

Relatively simple measurementRelatively simple measurement


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Maximum Bite ForceMaximum Bite Force

Unilateral molars : 300Unilateral molars : 300--600 N600 N

Premolars : 70 %Premolars : 70 %

Front teeth : 40 %Front teeth : 40 %Bilateral molars : 140 %Bilateral molars : 140 % -- 200 % (PVDF)200 % (PVDF)

Maximum (Eskimos) : 1750 NMaximum (Eskimos) : 1750 N (Waugh 1937)(Waugh 1937)

Hagberg 1987, Bakke et al 1989,

Ferrario et al 2004, Tortopidis et al 1998


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Maximum bite forceMaximum bite force

Depends on number of teethDepends on number of teeth

Gender differenceGender difference

Importance of motivation and cooperationImportance of motivation and cooperation

Rugh and Solberg 1972


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Influence of pain : arthritis or TMD resultsInfluence of pain : arthritis or TMD results

in decrease of 40 %in decrease of 40 % (Wenneberg et al 1995, Stohler(Wenneberg et al 1995, Stohler1999)1999)

Correlated to PPTCorrelated to PPT (Hansdottir and Bakke 2004)(Hansdottir and Bakke 2004)


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Influence of age (constant from 20Influence of age (constant from 20--50 y,50 y,

decreases later,decreases later, Bakke et al 1990Bakke et al 1990))

Decreases with increasing facial height,Decreases with increasing facial height,gonial angle, (gonial angle, (Ingerval & Helkimo 1978, ThrockmortonIngerval & Helkimo 1978, Throckmorton

et al 1980, Proffitt et al 1983, Braun et al 1995et al 1980, Proffitt et al 1983, Braun et al 1995))

No influence of tooth decay or loss ofNo influence of tooth decay or loss of

periodontal support (periodontal support (Miyaura et al 1999, Morita et alMiyaura et al 1999, Morita et al

20032003))


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Dentures....Dentures....

..and implant-support helps(Bakke et al 2002, Van Kampen et al 2002)


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Malocclusion and bite forceMalocclusion and bite force

Negative influence of :Negative influence of :

-- overjet on incisal MBFoverjet on incisal MBF (Ahlberg et al 2003)(Ahlberg et al 2003)

-- unilateral crossunilateral cross--bitebite (Sonnesen et al 2001)(Sonnesen et al 2001)

-- open biteopen bite (Bakke & Michler 1991)(Bakke & Michler 1991)


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ConclusionsConclusions

Occlusal contact area seems mostOcclusal contact area seems most

correlated, more than malocclusioncorrelated, more than malocclusion

Butdoes it matter,sinceButdoes it matter,since

-- only 10only 10--20 % of variation explained20 % of variation explained

(while e.g. thickness of masseter explains 55 %...)(while e.g. thickness of masseter explains 55 %...)

-- normal chewing forces are only 15normal chewing forces are only 15--30 %30 %

of MBF.of MBF.


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Masticatory ability and performanceMasticatory ability and performanceP.H. BuschangP.H. Buschang

Anatomical (occlusal contact area,Anatomical (occlusal contact area,malocclusion ); physiological (musclemalocclusion ); physiological (musclestrength, training, gender,) andstrength, training, gender,) and

psychological components interplay inpsychological components interplay inmastication, and deficiencies in one partmastication, and deficiencies in one partcan be compensated for by otherscan be compensated for by others

Masticatory performance is an objectiveMasticatory performance is an objectivemeasure, directly linked to foodmeasure, directly linked to foodbreakdown, nutrition, digestionbreakdown, nutrition, digestion


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Masticatory performanceMasticatory performance

Particle size distribution of (testParticle size distribution of (test--)food,)food,

chewed a standard number of cycleschewed a standard number of cycles

Methodology : fractional sievingMethodology : fractional sievingTypical food (peanuts, carrot, bread,)Typical food (peanuts, carrot, bread,)

Optosil, or specially developed testOptosil, or specially developed test--foodsfoods


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Masticatory performance isMasticatory performance is

influenced by :influenced by :

Number of teeth/occluding units (butNumber of teeth/occluding units (butsubjects with missing teeth do not chewsubjects with missing teeth do not chewlonger)(longer)( Helkimo et al 1978, Yurkstas et al 1965, HenriksonHelkimo et al 1978, Yurkstas et al 1965, Henriksonet al 1998et al 1998))

Patients with dentures increase thePatients with dentures increase thenumber of chewing strokes and waitnumber of chewing strokes and waitlonger to swallow (? Corrected for age )longer to swallow (? Corrected for age )

Mixed dentition : increase in early,Mixed dentition : increase in early,decrease in late phasedecrease in late phase


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MP and malocclusionMP and malocclusion

Less potent effect than mutilated dentitionLess potent effect than mutilated dentition

In crossIn cross--sectional studie, MP of Class IIIsectional studie, MP of Class III

patients is up to 60 % lower (patients is up to 60 % lower (English et al 2002,English et al 2002,Lundberg et al 1974, Zhou and Fu 1995Lundberg et al 1974, Zhou and Fu 1995). MP of Class II). MP of Class II

is 30 to 40 % lower (is 30 to 40 % lower (Henrikson et al 1998Henrikson et al 1998) but) but

Median ParticleS

ize (MPS

) was notMedian ParticleS

ize (MPS

) was notsignificantly different (significantly different (Toro et al 2006Toro et al 2006))


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MP and malocclusionMP and malocclusion

After a predetermined number of chewingAfter a predetermined number of chewing

cycles (20,30,40) , the Median Particlecycles (20,30,40) , the Median Particle

Size is larger in subjects with ICON (indexSize is larger in subjects with ICON (index

for complexity, outcome,need) < 43 thanfor complexity, outcome,need) < 43 than

> 43> 43

but no differences in particle distributionbut no differences in particle distribution

or masticatory frequency (or masticatory frequency (Ngom 2007Ngom 2007))


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MP and digestionMP and digestion

Animal experiments clearly indicateAnimal experiments clearly indicate

relation between food particle size andrelation between food particle size and

digestion (digestion (Gyimesi et al 1972Gyimesi et al 1972))

In man, also incompletely chewed food isIn man, also incompletely chewed food is

digested. In elder persons, MP has beendigested. In elder persons, MP has been

linked to GIlinked to GI--problems : 49 % of patientsproblems : 49 % of patients

without posterior teeth have gastritis vswithout posterior teeth have gastritis vs6 % when no teeth are missing (6 % when no teeth are missing (Mumma 1970Mumma 1970))


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Mastication and developingMastication and developing

occlusionocclusion

Over the centuries, malocclusion seems toOver the centuries, malocclusion seems tohave increased 10have increased 10--fold and modern lifefold and modern life--style and nutrition have been suggestedstyle and nutrition have been suggested

as cause (as cause (Corrucini 1984, Varrela 1990,1992Corrucini 1984, Varrela 1990,1992), even), evenmore than genetics (more than genetics (Townsend et al 1998Townsend et al 1998))

Nutrition influences elevator muscleNutrition influences elevator muscledevelopment and muscle functiondevelopment and muscle functioninfluences transverse and vertical facialinfluences transverse and vertical facialdimensions (dimensions (Kiliaridis 2006Kiliaridis 2006))


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CONCLUSIONSCONCLUSIONS

Malocclusion influences the chewing cycleMalocclusion influences the chewing cycle

Number of occlusal contacts and unitsNumber of occlusal contacts and units

influences the maximum bite forceinfluences the maximum bite forceClass II and III patients have a lowerClass II and III patients have a lower

masticatory performancemasticatory performance

but.but.

Probably not ofProbably not of clinicalclinical significance in nonsignificance in non--

compromised patientscompromised patients


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importance of occlusion in oral function

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