Integrated Restorative Flashcards
endodontic lesion with periodontal involvement
inflammatory lesion originating in the pulp however, it will manifest in the periodontium; this lesion may mimic periodontitis
if incorrect diagnosis & perio therapy undertaken with curette this will destroy PDL & compromise prognosis of tooth
periodontal lesion with endodontic involvement
inflammatory lesion in the marginal periodontium but manifests in the pulp
if plaque only colonises the external root surface there is limited effect on a normal healthy pulp
pulp necrosis may occur when the periodontal process extends to apical foramen; prognosis here is poor
true combined lesion
both an endodontic lesion & periodontal lesion occurring simultaneously & independently
tx of perio-endo associated teeth
e.g. ptx has periodontal abscess on 1 tooth yet extensive pocketing & bone loss it is likely to be arising from perio disease so tx should be sub gingival debridement
or if pocketing is isolated to 1 tooth the tooth should be endodontically treated
if uncertain but tooth is non vital the endo tx tooth & observe response
5 properties of occlusal forces to be taken into consideration
- magnitude
- velocity
- frequency
- duration
- direction
what are the ideal occlusal contacts in the ICP
posterior = lower buccal cusps should occlude against marginal ridges and fossae of opposing teeth
anterior = lower incisal edges & canine tips will occlude against cingulum
what is the ICP
intercuspal position - the position of the jaws when the maxillary and mandibular teeth are in maximum intercuspation
what is canine guidance
in canine guided occlusion, the overlap of maxillary and mandibular canines results in disengagement of maxillary and mandibular posterior teeth during excursive movement of mandible i.e. in excursions one or more anterior teeth contact & there is immediate discursion of teeth on the non working side
what is group function
multiple contact relations between the maxillary and mandibular teeth in lateral movements on the working side i.e. the simultaneous contact of numerous teeth acts as a group to distribute occlusal forces on the working side & there is disclusion of teeth on the non working side
TMJ movement
TMJ will move differently depending on which side the jaw is moving to laterally - side jaw is moving towards is called the working side - this condyle will rotate & the non working side will be the side in which the mandible moves away from - this condyle will translate downwards, forwards & inwards i.e. it will orbit
name the 3 forms of tooth guidance
- canine guidance
- group function
- balanced articulation - complete dentures only
normal function
most tooth contact in chewing & swallowing will occur in maximum intercuspation
parafunction
purposeless clenching & grinding which causes greater & longer forces than the teeth are put under during normal function that can cause damage to teeth, periodontium, muscles, joints
what is posselt’s envelope
refers to range of motion of mandible
what is RCP
Retruded contact position (RCP) also known as centric relation, describes the relationship of the mandible to maxilla when the mandibular condyles are in their most superior and anterior position in the articular fossa, independent of tooth contact - this is an easily reproduceable position
rotational movement according to posselts envelope
In the TMJ, the initial mouth opening occur by rotation, within the inferior cavity of the joint
the TMJ rotates around a fixed axis within the condyle, with no antero-inferior translation
the maximum jaw opening with this rotation movement is indicated as ‘R’ on the Posselt’s envelope of motion
translation according to posselts envelope
when the jaw is opened wide, it exceeds the maximum range of jaw opening with rotational movement, and a secondary gliding movement occurs i.e. translation which occurs within the superior cavity of the joint
During translation, the condylar heads slide anterior and inferiorly down the articular eminence, allowing the jaw to open wider. This path of movement is the line produced between ‘R’ and ‘T’, where ‘T’ indicates the maximal jaw opening with full translational movement
edge to edge in posselts envelope
Edge-to-edge articulation is when opposing front teeth meet along their incisal edges when teeth are in maximal intercuspal position - this is in ICP
maximum protrusion in posselts envelope
When the lower jaw is pushed anteriorly as far as possible with some teeth in contact, it is said to be maximum protrusion
mounting casts in an articulator
upper = this requires a facebow - this will transfer the relationship between the maxillary teeth & axis of rotation from the patient to the articulator
it will position the upper cast vertically & the angulation of the occlusal plane in relation to a horizontal reference plane
lower = mounted in ICP or RCP
registering the occlusion
if ICP used and the 2 casts fit together obviously then no registration medium is needed
if no obvious ICP then a registration medium is required & it must not alter vertical dimension & must allow natural occlusal stops
when not using ICP how to mount casts
to take this occlusion (RCP) the mandible must be manipulated so there is no muscle resistance & push the mandible back to register
as there is to be a new IP a registration is always required
it should be as thin as possible without allowing occlusal contact as occlusal contact will malform the retruded arc
process of restoring worn anteriors
- impressions taken
- diagnostic wax up on casts
- acrylic mould of wax up
- filled with temporary material and attached to teeth
- impressions taken again
- custom anterior guidance table produced from impressions
- crowns produced to new guidance
2 forms of horizontal force placed on teeth
- constant - only in orthodontic appliances
- intermittent - forces the teeth are put under all the time
in a healthy periodontium with abnormal occlusal forces
there will be no gingival inflammation and no change in attachment this is because periodontitis is a plaque related disease
in healthy periodontium with excessive abnormal occlusal forces
if the load is too great it becomes pathological; this is where the load will be too great for the adaptive capacity of the PDL leading to continued increase in PDL width
occlusal trauma
tooth mobility which is progressively increasing and / or mobility associated with symptoms - there must be radiographic evidence of increased PDL width (think of wiggling post in the ground)
occlusal forces & periodontitis
there will only be vertical bone loss due to the 2mm radius of destruction around plaque
there may be increased rate of disease
progression with both acting together & there may be greater levels of attachment loss at the overlapping
areas of the plaque induced inflammation and trauma
induced inflammation. However alone occlusal forces will not exacerbate gingival inflammation
4 factors determining tooth mobility
- width of PDL
- height of PDL
- inflammation
- number, shape & length of roots
what can improve perio related tooth mobility & why
if plaque adequately removed from teeth then there may be healing of periodontal tissues which will increase tissue tone due to increased collagen fibres thus producing a long junctional epithelium which can improve mobility
3 causes of tooth migration
- loss of periodontal attachment
- unfavourable occlusal forces
- unfavourable soft tissue profile
deep traumatic overbite
upper incisors stripping lower gingivae - trauma relieved using occlusal splint & ortho management, occlusal stops for anterior teeth may also be needed, any plaque related inflammation must also be treated
why must perio be arrested before restorative procedures
if inflamed gingival margin it is likely to bleed during operative procedures & its apico-coronal location is unstable so there may be moisture contamination & could be exposure of a restorative margin