Wear Flashcards
Causes of non-carious tooth surface loss
Trauma
Developmental problems
Tooth wear
Types of tooth wear
Physiological- normal- 20-38um per annum
Pathological:
remaining tooth structure/pulpal health compromised
rate of tooth wear> than expected for age
masticatory/aesthetic deficiency
Causes of toothwear
attrition
abrasion
erosion
abfraction
What is attrition
physiological wearing away of tooth structure as a result of tooth to tooth contact
found on occlusal and incisal contacting surfaces
Early appearance of attrition
polished facet on cusp/slight flattening of incisal edge/cusps
Progression of appearance of attrition lesions
reduction in cusp height
flattening of occlusal inclined planes
shortening of clinical crown of incisor and canine teeth
Cause of attrition
parafunctional habit (bruxism)
What is abrasion
physical wearing away of tooth structure through an abnormal mechanical process independent of occlusion
includes foreign objects/substance repeatedly contacting tooth
commonly found on labial/buccal, cervical on canine and premolar teeth
characteristics of teeth with abrasion
V shaped or rounded lesions
sharp margin at enamel edge where dentine is worn away
can manifest as notching of incisal edges
Cause of abrasion
Tooth brushing
habits/lifestyle: holding pins, nails, electrical wire stripping, fishing line, thread, pipe smoking, cracking sunflower seeds
What is erosion
Wearing away of tooth structure by chemical process that does not involve bacterial action
Cause of erosion
chronic exposure of dental hard tissues to acidic substances which can be intrinsic or extrinsic
characteristics of erosion
Typically bilateral, concave lesions without chalky appearance of bacterial acid decalcification
Increased translucency of incisal edges
Base of lesion not in contact with opposing tooth
Amalgam and comp. restorations stand proud of tooth
Early appearance of erosion
enamel surface detail affected, surface becomes flat and smooth
Progressed appearance of erosion
Dentine becomes exposed
Preferential wear of dentine leads to cupping of occlusal surfaces of molars + incisal edges of anteriors
What is abfraction
loss of hard tissue from eccentric occlusal forces leading to compressive + tensile stresses at cervical fulcrum of tooth
Characteristics of abfraction
Pathological loss of tooth substance at cervical margin
V shaped tooth loss where tooth is under tension
Sharp rim at ACJ
Restorations in area, wear at same rate as tooth structure
Cause of abfraction
Biomechanical loading forces
Forces result in flexure and failure of enamel and dentine at area away from loading
Disruption of ordered crystalline structure of enamel and dentine by cyclic fatigue
Cracks in tooth substance-chips out
MH linked to toothwear
Medications with low pH/which cause dry mouth
Eating disorders
Alcoholism
Heartburn/GORD
Hiatus hernia
Rumination
Pregnancy
SH linked to toothwear
lifestyle stresses- grinding
bruxism
occupation
alcohol/diet/habit/sport
What to record on wear examination
- Location:
anterior/posterior
localised/generalised - Severity:
enamel only
into dentine
severe
Examples of wear indices
Smith and Knight Index
BEWE(basic erosive wear exam)
What is the Smith and Knight Index
0- no loss of enamel surface detail
1- loss of enamel surface detail
2- B/L/O complete loss of enamel, exposing dentine for <1/3rd of surface incisal enamel loss
minimal dentine exposure
3- B/L/O complete loss of enamel, exposing dentine for>1/3rd of surface incisal enamel loss
substantial dentine exposure
4- B/L/O complete enamel loss, pulpal exposure/secondary dentine exposure
BEWE scores
0- no erosive wear
1- initial loss of surface texture
2- distinct defect; hard tissue loss <50% of surface
3- hard tissue loss>50% of surface
BEWE risk level for cumulative score of all sextants
None- less than or equal to 2
Low- between 3&8
Medium- between 9&13
High-14 and over
Special tests for tooth wear
Radiographs
sensibility tests
articulated study models
intra oral photographs
salivary analysis
diagnostic wax up
dietary analysis
How to diagnose toothwear
- Determine primary causative factor
- Identify patterns: localised, generalised
- Assess if dento-alveolar compensation has occurred
Immediate stage of preventative plan
Deal with pain
When do you create a prevention plan?
Once you have a dentally fit patient, diagnosis and have identified primary causative factor
Key element in prevention
Removal of cause
Abrasion prevention
Remove foreign object/substance causing abrasive wear
Change toothpaste/brushing habits
Change habits
Tx of toothbrush abrasion
Simple RMGIC=best survival rate, GIC or comp, can also be considered
No tooth prep
pt wears through restoration rather than damaging tooth
Attrition prevention/tx
Difficult to prevent as related to parafunctional habit-stress
CBT
Hypnosis
Splint
Splint advantages
Cause no damage to opposing teeth
Habit breaker
Soft splint=can be used as a diagnostic device(wear for 2 weeks)
Hard splint=more robust and can be used long term
Advantages of Michigan splint (type of hard splint)
Provides ideal occlusion with centric stops
Has canine rise which provide disclusion in eccentric mandibular movements
Provides canine guidance
Erosion prevention
Fluoride e.g. Duraphat
Desensitising agents
Dietary management esp. if extrinsic acid
Habit changes: use straw, vegan diet, rumination, overly healthy eating, sports drinks
Medical conditions control: gastric acid, GORD, reflux, hiatus hernia, xerostomia, anorexia and bullimia
Abfraction prevention
consider occlusal equilibrium
Fill cavity with low modulus restorative materials=RMGIC or flowable comp
What is passive management of tooth wear
First part of tx
Prevention and monitoring
For about 6 months
Requirements to progress to active management
Wear leading to further complications/more complex tx being needed
Aesthetics have gone beyond pt acceptability
Goal of active management
Preservation of remaining tooth structure
Pragmatic improvements in aesthetics
Functioning occlusion
Stability
5 factors in deciding tx of maxillary anterior tooth wear
- pattern of wear
- inter occlusal space
- space required for planned restorations
- quality/quantity of remaining tooth tissue/enamel
- Aesthetic demands of pt
Patterns of maxillary incisor wear
- Wear limited to palatal surface
- Wear involving palatal and incisal edges with reduced clinical crown height
- Wear limited to labial surface
Tx for different patterns of maxillary incisor wear
composite
In what cases is there adequate inter incisal space in maxillary anterior teeth
If wear is rapid and no time for alveolar compensation
AOB
Increased OJ
How to create space for restorations
- Increase OVD: multiple posterior extra-coronal restorations
- Occlusal reorganisation from ICP to RCP
- Surgical crown lengthening
- Elective RCT + post crowns
- Conventional ortho
What is the DAHL technique?
-Method of gaining space in localised tooth wear
-Cover palatal surfaces on incisors and canines with composite allowing occlusion on raised cingulum
-Results in posterior disclusion and 2-3mm increase in OVD
-Anteriors intrude and posteriors erupt, results in space between upper and lower anteriors allowing restorations with no need for occlusal reduction
-If no movement in 6 months, won’t work
Why do you use composite in DAHL technique and not CoCr
Better aesthetics
Better compliance as not removable
Easier to adjust
Immediate or definitive tx
Contraindications of DAHL
Active perio
Post ortho
Bisphosphonates
If dental implants
If existing conventional bridges
Anterior wear tx contraindications
short roots
reduced periodontal support due to perio disease
lack of remaining enamel reduces success rate significantly- enamel ring of confidence positively influences success rate
Why is lower anterior wear more difficult to treat
less enamel-smaller bonding area
Tx of localised posterior tooth wear
If localised and asymptomatic, prevention and monitoring are appropriate
Occlusal erosive wear can be filled directly with comp with no change in occlusion
Loss of canine guidance common cause
How to correct loss of canine guidance for posterior wear
Add comp to palatal of upper canines to increase canine rise and disclude posteriors during lateral and protrusive excursions- can use comp free hand or with diagnostic wax up
Why is pathological wear more common in upper than lowers
Tongue and saliva protects lowers
Methods of composite build up
putty matrix
wax up
alginate impressions
pickle juice habit
3 categories for generalised and localised tooth wear
- Excessive wear with loss of OVD
- Excessive wear without loss of OVD but with limited space
- Excessive wear without loss of OVD but with no space available
Adhesive approaches to generalised tooth wear
Adhesives used to assess patient tolerance of new occlusal scheme as medium term restoration
If conventional preps are required at later date, these adhesive addition may form the bulk of removed material-preserving tooth structure
Tx of excessive wear with loss of OVD
-splint can be used to assess pt tolerance of new face height or use adhesive approach
-ideally half the OVD increase should be maxillary and half mandibular
-often mixture of adhesive and conventional restorations required
Tx of excessive wear without loss of OVD but with limited space
Can involve reorganisation of occlusion
Splint should be considered as increase in occlusal facial height required
Restoration of anterior and posterior teeth carried out at new occlusal facial height-if possible should involve minimum adhesive restoration
Treatment of excessive wear without loss of OVD but with no space available
Requires specialist opinion prior to Tx
Attempt to increase OVD by use of splints +/- dentures if lack of posterior support or if enough teeth use adhesive restorations
Crown lengthening surgery
Elective RCT
Ortho
Overdentures
Crown lengthening disadvantages
May result in black triangles between teeth where ID papilla is further down
Can lead to unfavourable crown:root ratio=increased tooth mobility if tooth loaded subsequently
Post op sensitivity
Any subsequent conventional crown prep will be further down root, problematic if tooth has significant coronal-cervical taper and has greater chance of pulpal damage
Overdenture features
preserves tooth structure and bone for support of denture when teeth are so worn down that Rx is impossible
can be bulky
difficult keeping teeth and gingivae healthy beneath denture
