Toothwear Flashcards
What is toothwear?
The pathological non carious loss of tooth tissue
What is the normal amount of toothwear per annum?
20-30um
30y+ =1mm wear
60+ = 2mm wear
What are the usual toothwear concerns?
Aesthetics
Function
Sensitivity
Rate
What is attrition?
The loss of tooth substance or a restoration as a result of contact between occluding surfaces
What is abrasion?
The physical wear caused by materials other than tooth contact
- nail biting
- pen chewing
- overzealous tooth brushing
- oral piercings
- restorations
What is erosion?
Loss of tooth tissue due to chemical processes not involving bacterial action
key sign - enamel cupping
What are extrinsic acids?
Acidic drinks/food
Buccal/cervical surfaces of the maxillary teeth and the occlusal surfaces of mandibular posterior dentition
What is intrinsic acid and where does it act?
Mandibular dentition tend to be protected by tongue
stomach acid
acts on the palatal surfaces of the maxillary dentition
What do erosive enamel lesions look like?
Rounded and smooth with surface enamel loss
Increased translucency, e.g. at incisal edge
Chipped enamel
Proud restoration margins
Gloss of enamel and surface anatomy losss
What do erosive dentine lesions look like?
Dentine more susceptible to erosion then enamel - more rapid loss of dentine
Cupping/dished out lesions
Teeth appear darker due to exposed dentine
What does an active erosive lesion appear to look like?
No staining on teeth
Enamel = loss of lustre
Hypersensitivity
What does an inactive enamel lesion look like?
May be stained if dentine is exposed
What is abrfraction?
Tooth wear located in the cervical area caused nu flexural forces during function and parafunction
angular wedged lesions at CEJ
Result to flexure and fracture of enamel/cementum
Tend to be more angular and undercut than erosive/abrasive lesions
Evidence regarding correlation with occlusion but evidence not conclusive
Likely to have multifactorial aetiology
What are the risk factors for toothwear?
Parafunctional habits e.g. bruxism
Enamel/dentine anomalies - amelogenesis imperfecta
Saliva
MH
Intrinsic/extrinsic acid
What are parafunctional habits
Bruxism, clenching, lip biting, thumb sucking and any other oral habit not associated with mastication, deglutition and speech
Significant increase in duration and frequency of occlusal forces
What is the normal occlusal force?
200N
Why does saliva play an important role in erosion?
- eliminates acids
- presents buffering capacity causing neutralisation
- flow of saliva allows dilution of acids
- super saturated with ca and po4 for remineralisation
- proteins present in saliva and acquired pellicle play an important role in erosion
What factors increase xerostomia?
Head and neck RT
Salivary gland disorder e.g. sjogrens
Medications
Diabetes
What is the histopathology of erosion?
Chemical dissolution of tooth tissue caused by H+ ions and anions capable of binding to calcium
- Early demineralisation and softening of the tooth tissue without surface loss
- Microscopic material loss
- Clinically visible erosive lesions
Histopathology of enamel
Loss of surface minerals causes an increase in roughness
Bulk mineral loss
Surface structure of eroded enamel corresponds more or less to a typical etching pattern
Partial loss of mineral at the surface results in softening of enamel and vulnerability to physical impacts
Enamel remains soft and vulnerable to abrasive injury after hours
IO saliva - limited remineralisation of softened surface
Solutions or preps of active agents applied, can gain minerals due to precipitation of various salts
Histopathology of dentine during erosion
Mineral component readily dissolves whilst organic portion is retained
Thin zone of dense fibrous collagen network present, increases depth with increasing erosion time
Depending on time of exposure, fully demineralised zone develops beneath where partially demineralised dentine is found
Peritubular dentine dissolves at a quicker rate than inter-tubular dentine
What are the acids that cause erosion?
Citric acid
Phosphoric acid
Malic acid
Damage depends on buffering capacity
Amount of undissociated acid present in food/drinks
Greater the buffering capacity of the drink, longer for saliva to neutralise
Why is citric acid so erosive?
1 acid molecule creates 3x hydrogen atoms
Citric acid has the increased capability to bind calcium ions - this can occur at higher pHs
What can be done to reduce erosivity of soft drinks?
Addition of calcium
Avoid swishing of drinks around mouth
Rinse acids out of mouth with neutral solution e.g. water after ingesting
Avoid abrasive activities, toothbrushing for up to 2hrs
Sources of intrinsic acids
Vomitting
Rumination
GORD
Sphincter incompetence - oesophagitis, hiatus hernia, diet, pregnancy, drugs, neuromuscular
Increased gastric pressure, obesity, pregnancy, ascites
Increased gastric volume - meals, obstructions, spasms
Vomiting disorders?
Psychosomatic - stress, eating disorders, anorexia etc
Metabolic and endocrine - diabetes, pregnancy and uraemia
Gi - peptic ulcers, obstructions, cerebral palsy and nervous system disorders
Drug induced - primary - cytotoxic, secondary - NSAIDS, alcohol, aspirin
Basic erosion wear examination
0 - no erosive wear
1 - initial loss of enamel surface texture
2 - distinct defect, hard tissue loss extending to loss than 50%
3 - Hard tissue over 50% loss
BEWE score of 9-13 (medium)
OH, dietary assessment
Routine maintenance
Fluoride measures
Avoid restorations
Repeat at 3-6m intervals
BEWE score of 14+
As in medium
Consider restorations
What are the benefits of a BEWE?
More easily applied to practice settings
Includes management of tooth wear as well as diagnosis and staging
Recall recommendations included
Ability to assess if toothwear is localised/generalised
Can be used to monitor tooth wear over time
What are the disadvantages of BEWE?
Erosion only
Larger discrepancies measuring enamel lesions
What 5 factors are measured in the anterior clinical erosive index?
Dentine exposure in contact areas
Preservation of incisal edges
Length of remaining clinical crown
Presence of enamel on vestibular surfaces
Pulp
Benefits of anterior clinical erosive index
Detailed classification staging
Recommended treatment options
Idea od prognosis of restorations given
Useful to review a patient over time
What are the disadvantages of clinical erosive index?
Anterior teeth only
Does not cover diagnosis/tx options for posterior teeth
What advice can be given after extrinsic acid consumption
Consuming dairy products
Chewing gum following acid exposure
- re hardening of enamel
- stimulation of saliva flow
- increase in saliva pH
Which topical agents can be used in the rehardening of enamel?
Remineralising toothpastes - NaF and ACP
Fluoride
Neutral NaF mouthrinse/gel can be recommended
Avoid toothbrushing after acid exposure
Custom made trays for topical appl
Topical agents for hypersensitivity
Potassium - sensodyne daily care
CPP-ACP - calcium phosphopeptide amorphous calcium phosphate - increased precipitation of phosphate - hardening of dentine, closure of tubules
Bioglass - sensodyne complete protection - obstructs tubules
Arginine - colgate sensitive pro-relief
Advice to avoid abrasion
Tooth brushing advice
Use of less abrasive toothpastes
Avoid tooth brushing after acid exposure
Stop prevent
Remove oral piercings
Appropriately plan restorations
Advice to prevent attrition
Splint therapy - full coverage hard acrylic splint - michigan/tanner
Thermoform
Bilaminar - hard and soft layer. must provide balanced occlusion with all teeth in contact with splint
(soft splints can increase parafunctional habits and lead to orthodontic movement of teeth)
How can space be created for restorations?
Crown lengthening surgery - increase height of teeth to aid retention and can improve gingival aesthetics which does not create space in itself - increased SA of tooth for cement/bond to
Elective RCT - destructive which worsens prognosis of tooth - posts and cores to maintain restorations
Occlusal reduction of teeth to be restored - destructive
Occlusal reduction of opposing teeth - only in select cases
Assessing restorability of worn teeth
Look for ring of enamel to bond to
Remaining clinical crown height for resistance and retention form
Pulp status of tooth
Perio status of tooth
How to perform a diagnostic wax up
EO assessment of dentition
Occlusal relationships, contacts and interferences
Restorative space available
Plan occlusal changes
Clin stages - maxillary and mandibular impressions
Capture desired OVD with a jaw reg
Wax up at desired OVD
What are the benefits of using a hard acrylic full coverage splint?
Protect teeth from further wear
Management of TMJD
Testing pt tolerance of an increased OVD
Disrupts habitual path of closure in ICP
How is a hard acrylic full coverage splint designed?
Bilateral occlusal contact along the retruded arc of closure
Anterior guidance on anterior teeth and canine guidance in lateral excursion
Posterior discussion in excursions
AVOID partial and soft splints
Indications of managing toothwear
Pain/discomfort
Aesthetics
Function disrupted
Compromised structural integrity of tooth/teeth
Alveolar compensation with reduced interocclusal space for restoration
What are the contraindications of managing toothwear?
Perio and caries
Unrestorable teeth - vertical height
Root fractures
Horizontal/oblique fractures to bone crest, caries to bone crest and failed endo
Extensive edentulous spans, insufficient posterior support and dental implants are not considered
What is the Dahl concept?
Localised appliances/restorations placed in supra-occlusion
Occlusion re-establishes and arch contacts over a period of time
Originally removable CoCr bite raising appliances used
After 8m, sufficient space created to provide palatal gold onlays
Basic principles of Dahl
- Thickness of material = amount of inter occlusal space required
Increase OVD
Ideally ensure that occlusal forces are directed against the long axis of the tooth
Stable interocclusal contacts
Appliance/restoration should not impede movement of discluded teeth
How much space can be created?
1.8 - 4.7mm av = 2.84
What is the ratio of intrusion v eruption
Intrusion - 40%
Eruption = 60%
How long can it take for re-establishment of occlusal contacts?
6m but can be up to 18-24m
What are the adverse effects/symptoms?
4% reversible pulpal
3-10% reversible perio tenderness
2-4% reversible TMJ
No root resorption reports
Partial occlusal re-establishment often involving premolars
Posterior toothwear management
monitor and review
composite added superior to centric stops palatally (+/- wax up)
Indirect restorations
Provides separation of posterior teeth on mandibular excursions to prevent further wear
How much more wear does composite have than an indirect?
3-4x but composite restoration involve more minimal prep to tooth
Occlusal reduction for different indirects:
PFM - 2mm
Metal onlay - 1mm
Metal veneers - 0.7mm
Zirconia - 1mm
Composite -1-2mm
What is an overdenture?
Completely covers on one or more natural teeth and a flange
- When teeth worn down to gingival level or unrestorable
What is an overlay denture?
Cover teeth with full labial veneer facing as well as occlusal coverage
Used when flange not indicated - undercuts/aesthetics)
What is an onlay denture?
Cover entire occlusal/incisal surface
Indicated when 1/3 to 1/2 of coronal tooth present, healthy remaining tooth tissue and acceptable aesthetics
What are the benefits of overdentures?
Psychological benefit of tooth retention
Continued proprioceptive feedback from PDL
Decreased ridge resorption
Additional retention from abutments
Replace soft tissue
Disadvantages of overdentures
Reduction in prosthetic space
Increased incidence of caries and perio
Risk of pulp inflammation/exposure when replacing abutment teeth
Complex to provide
High maintenance regime
What features must an overdenture abutment have?
1.5-2mm supragingival tooth tissue
Dome shaped
Min 5mm alveolar bone support
Band of attached gingivae
Maintenance of overdenture abutment
High risk of caries and perio
Regular review and OH reinforcement
- brush abutment with high F toothpaste
- daily F mw
- apply high F gel to fit surface in AM and do not eat for 30m afterwards
- Dentures out at night
- Clean dentures after meals
