interdental relations

Interdental relationsInterdental relations

= contact between neighboured teeth and teeth in oppposite dental arches , if they are in contact.

Interdental relations :

horizontal vertical

(horizontally, approximally) (vertically, occlusallly)

contact points intercuspidation


Vertical interdental relationship = teeth in ideal position make contact between cusps and opposite fissures of opposite dental arch.

Inclination of distal teeth :

- In maxilla are teeth long axis palatally inclinated,

- In mandible are crowns of distal teeth turned lingually


Principles :

• In maximal intercuspidation of regular teeth – upper frontal teeth cover frontal lower teeth upper dental arch is wider than lower dental arch = basic of occlusion .

• Occlusal linea (biting linea ) = linea where upper and lower dental arches are in full contact .

Interdental relationsInterdental relations • Occlusal contact - contact of surfaces of opposites teeth in

both dental arches in position of maximal intercuspidation .

• Sum of surfaces is named occlusal field .

• Height of bite = distance between bases of upper and lower fornices vestibuli oris measured in frontal part in position of maximal intercuspidation.

• Supportive zones – opposite teeth groups (same type), which are in contact in occlusion. Functionally in permanent teeth are distinguished : premolar´s and molar´s supportive zones .


• Occlusio – occlusion = any contact between teeth in maxilla and mandible.

• Static occlusion – habitual intercuspidation =

– status when cusps of one dental arch are in contact in intercuspal fissures of opposite dental arch.

– between upper and lower teeth is maximal number of contacts. Chewing movement is stopped.

– during habitual occlusion teeth are in intercusp position .


Dynamic occlusion

( former named as a articulation )

– status when cusps of one dental arch glide on group of cusps of opposite teeth,

– maxilla and mandible are in motion and grind the food.

Static and dynamic occlusion are mutually influented between themselves by 3 factors :

Factor 1 :

= slant of cusps , borders and fissures on occlusal surfaces premolars and molars.

Inclination of slants conditione lateral line of mandible during mastication. Anterio-posterior line is done by inclination of palatal surface of upper incissors and canines. Under dominant participation is distinguished incissal line or canine line.

Static and dynamic occlusion are mutually influented between themselves by 3 factors :

Factor 2 :

inclination of dorsal slant of articular cusp of TMJ and on this perpendicular roof-like shape of TMJ - head.

Factor 3 :

active factor is represents by masticatory muscles.

Static and dynamic occlusion are mutually influented between themselves by 3

factors :

On cusps are prominentiae of different shapes :

triangle

central

additive

Traumatic occlusionTraumatic occlusion

Status where on periodontium develop pathologic changes by influence of higher forces on occlusal tooth surface.

The force of is higher than periodontiun is capable to transport without tissue damage.

•Its absolut size is individual and different, periodontal reaction depends on periodontal immunity, logevity of influence and age of patient

Traumatic occlusion Traumatic occlusion

higher power ⇨ healthy periodontium

higher power ⇨ diseased periodontium

physiologic power diseased ⇨ periodontium


• Primary - includes changes on healthy periodontium, e.g. high filling, bruxisms drifting or extrusion into edentulous spaces, and orthodontic movement.

• Secondary – includes changes which influent pathologically changed periodontium.

– they are differences when primary are present

inflammation or atrophy.


3) Combined Occlusal Trauma: Injury from an excessive occlusal force on a diseased periodontium

In this case, there is gingival inflammation, some pocket formation, and the excessive occlusal forces are generally from parafunctional movements.

Clinical signs

•Mobility

•Pain on chewing or percussion

•Fremitus

•Occlusal prematurities/discrepancies

•Wear facets in the presence of other clinical indicators

•Tooth migration

•Chipped or fractured tooth (teeth)

•Thermal sensitivity

Radiographic findings

•1) Widened - increased periodontal membrane space

•2) Bone loss (furcations; vertical; circumferential)

•3) Root resorption

Goals and rules of correction : Goals and rules of correction : • To apply forces, which influent on whole alveolar ridge to be

transport in each position of occlusion on maximal teeth (the best on all teeth )

• The occlusal force cannot be directed only on one tooth or group of teeth

• The power influent on one tooth must applied on big field , not on small point or margin of occlusal surface of tooth

• To reduce inclination of contact surfaces and reduce the height of clinical crown of tooth

By coreection cannot be By coreection cannot be :

• Reduced teeth function , it means food grinding, phonation, esthetic in frontal teeth

• Reduced the biting heigh ( TMJ disorders)

• Permanently excluded some tooth from centric oclusion (by active eruption – prolonged tooth clinical crown )

Determination of premature teeth contact Determination of premature teeth contact in centric occlusion :in centric occlusion :

1. Examination of centric occlusion : determine premature teeth contact and after position of occlusal contact

2. Wax bite

3. Model + articulating papers

4. Clinical examination :

abrased fasets on occlusal tooth surface, anemisation of gingiva around affected tooth, anomal tooth position


5. Recording of centric or excentric occlusion = contact of both dental arches – patient sit with inclinated head, during mouth closing is tip of tongue positioned on hard palate – silent positon

6. Basic principle of grinding = never gring cusp, which is not in occlusion – consequence : increasing the distance between teeth in opposite dental arch


7. Determination of frontal and lateral occlusion = biting on incisal edge of incissors and on left and right cusps – movement of mandible anteriorly or laterally = in contact are only the teeth which guided surfaces are longer and other teeth are not in contact .

Occlusal relations

• Upper canine in regular dentition in complete bite fall into between lower canine and lower first premolar. Relation of canine is called as key of frontal occlusion.

• Key of lateral occlusion – position of first molars

• Occlussal contact - reciprocal touch of small and large surfaces of antagonistic teeth in both dental arches in position of maximally intercuspidation.

The sum of these surfaces is called as occlusal field.

Occlusal relations

• Overbite (in vertical linea) : determines the depth of bitting : the bitting margins of upper incissors cover vestibular surfaces of lower incissors.

• Overjet : incisal edge is in horizontal linea the bitting margins of upper incissors are in front of margins of lower incisors.

• Physiologic overjet and overbite = 2 mm

Occlusal relations• The height of biting

distance between basis of upper and lower vestibulum oris (fornices vestibuli oris ) measured in frontal area in the position of maximal intercuspidation

• Supportive zone – are formed by opposite teeth groups of same type, which are in the contact between themselves in occlusion.

• Functional aspect in permanent dentition : premolar´s and molar´s supportive zone

Occlusal relations

Occlusion Means any contact between teeth of upper and

lower dental arches.

static occlusion dynamic occlusions(habitual intercuspidation) (former articulation)

Occlusal relationsStatic occlusion – habitual intercuspidation

– - condition where cusps of the teeth in one dental arch inclinate ( fall) into intercuspidal fissure of the teeth in opposite dental arch.

• – between upper and lower teeth is maximal number of tooth contacts. The masticatory (chewing) process is stopped..

• – during habitual occlusion teeth are in intercuspidal position .

Occlusal relations

• Dynamic occlusion

– condition where cusps of the teeth in one dental arch glide on the group of cusps of opposite teeth.

• – maxilla and mandibula are in movement and grinde the food.

Occlusal relations

• In the silent period without movement the mandibula is in silent position , where teeth have distant between themselves 2 – 4 mm. This gap can be wider until to position of maximally opening the mouth,.

Occlusal relations• Working side = side where is directed lateropulsion of

cusps• Balance side = opposite side – where during median

movement the occlusal surfacess move away.• Protrusion movement of mandible forward movement ,is relatively short. In centric

occocclusion lower incissors are moved on palatinal surfaces of upper incissors , in direction downword until incissal edges

• Lateral movement of manbible – movement in lateral side, lateral movement of median line.

interdental relations

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