Cavity Preparation* Flashcards
Advantages and disadvantages to direct and indirect restorations?
Direct: - quick - one operator - simpler - cheaper Indirect: - increased fit - better margins - less shrinkage - better aesthetically
Main reasons for teeth restoration?
Caries
Non-carious tooth substance loss
Failed restorations
Aesthetics
Aims of restorations - step 1/2?
Step 1: remove diseased tissues
Step 2: restore integrity, function and appearance of tooth
Describe the restorative cycle?
A cycle which indicates the possible outcome for teeth
Main reasons for dental caries?
Plaque - from digestion of glucose to produce acid
Diet - affects pH
Caries - minimal intervention technique - definition?
The aim of restorations are to be minimally invasive and mainly preventative rather than reactionary.
Also, to identify and control aetiological factors and stabilise.
Types of non-carious tooth substance loss?
Attrition - tooth on tooth
Abrasion - wear
Erosion - chemical
Abfraction - functional (V/C shaped)
Main aim for cavity preparation?
Removal of infected dentine
Sealing dentinal tubules
Micro-preparation technique - what is involved?
Reduced size of instruments and size
Magnification necessary
Atraumatic restorative treatment technique - what is involved?
Hand excavation then restored with adhesive material
Nervous patients
Doesn’t removal all caries
The stages of treatment - Identify? Prevent? Restore? Maintenance?
Identify:
- history, examination, detection, radiographs and aetiological factors
Prevent:
- lesion type, patient susceptibility and proposed action
Restore:
- decide on productive treatment
Maintenance:
- susceptibility related and recall variable
Advantages of minimally invasive technique?
Less unexpected exposure of the pulp
Less pulp stress
Also, repair and refurbish where possible
Repair and refurbish technique - dependent upon? what is involved?
Depend: Patient wish History Caries risk Marginal defects existing Involved: - polishing, recontouring margin, or small replacement
Factors which affect the life of a restoration?
Caries risk Cavity size Cavity Ste Operator skill Trauma Lifestyle
Factors for failure of restorations?
Secondary caries Tooth wear Pulpal problems Trauma Fracture Ditching Defective contact Defective margins Aesthetics Lack retention
Secondary caries - cause failure?
Caries at margin
Gap left in restoration allowing food and bacteria to accumulate, and no cleaning potential leading to caries
Tooth wear - cause failure?
From attrition or erosion
Lose attachment
Pulpal problems - cause failure?
Causes pain
Direct or infection
Needs RCT or extraction
Trauma - cause failure?
Loss of restoration through force
Fracture - cause failure?
Incorrect placement
Material too thin
Tooth sections too thin
Occlusion
Ditching - cause failure?
At tooth-amalgam interface
Due to creep or corrosion
Plaque retentive -> 2nd caries
Defective contact - cause failure?
Food packing
Recurrent caries
Aesthetics - cause failure?
Look bad, replaced
Poor margins - cause failure?
Plaque retention, food trapping, recurrent caries and perio disease
Lack retention - cause failure?
Nothing to attach to
Break off
During cavity prep - what happens to the dentinal tubules?
Insult the pulp leads to increased inflamm cell infiltrate
Prep leads to smear layer which occludes dentinal tubules with bacteria, collagen slurry and hydroxyapatite
Pulpal chemical attacks - sources?
From restorative material such as acrylic resin and acids in dentine bonding agents
or residue acid from bacteria
Pulpal galvanic shock - what causes it?
2 different adjacent material restorations such as silver and gold can form a electrolyte cell with the saliva causing pain
Pulpitis - definition? causes? symptoms?
Pulpitis is the inflammation of the dental pulp
Causes:
- carious progression into dentine
- tooth has multiple procedures
- trauma to lymphatics or blood supply
Symptoms:
- increased response to hold and cold stimuli
Reversible pulpitis - definition? causes? symptoms?
Reversibility damaged but can recover Mainly due to bacterial invasion into dentine Symptoms: Transient pain to hot, cold, sweet, water and touch Lasts seconds Pulp still vital Can return to healthy state Referred pain
Irreversible pulpitis - definition? causes? symptoms?
Irreversible damage Mainly due to bacterial invasion of the pulp Symptoms: Dull aching from hot or cold Lasts hours Constant Spontaneous Sleep loss CS: more painful to heat
Reasons not to restore cavities?
Patient access to lesion is good
No active cavies
Possibility of remineralisation
What does minimally invasive mean and involve?
Remove unrepairable diseased enamel and dentine only
Physically and chemically modify the remaining cavity
Restore cavities with suitable material which supports and strengthens the structure, promotes remineral and seal of any remaining bacteria from nutrition arresting the carious process
Black’s classification of cavities? I - VI?
I: occlusal surfaces of molar and premolars, buccal pits of molars and palatal pits of anteriors
II: interproximal surfaces of posteriors
III: interproximal surfaces and anteriors
IV: incisal edges of anteriors
V: cervical margins
VI: cusp tips of posteriors and canines
Classification of caries - anatomical sites? overall type? speed?
Site: Pit or fissures Smooth surfaces Enamel Root Overall: Primary - on unrestored surfaces Secondary - develop adj to restoration Residual - demineral left before filling tooth Speed: Active Rampant - multiple lesion on uncommon sites Early childhood Arrested
Levels of disease (depth - D)? treatment response?
D1 - enamel lesions with intact surface
D2 - limited to enamel
D3 - in dentine
D4 - in pulp
D1/2 - preventative measures
D3/4 - restorative treatment
Black’s I - treatments? how to identify? what to do? maintenance? outdated?
Fissure sealants: RA BW radiographs (not good) Clean, wash and dry then transilluminate No sharp probes Preventive resin restoration: investigate minimal caries resin into cavity, then seal routinely checked Amalgam is outdated - removal of more tissues to create retention
Black’s II - how to identify? site? cavity access? amalgam vs composite?
Interproximal areas are stagnation areas where plaque can form
Found on BW radiographs:
- confined to enamel allows encourage to arrest via fluoride application
- visible in dentine needs restorative treat
Restored with amalgam or composite
Accessed via marginal ridge, with matrix band
Needs undercuts to facilitate retention of amalgam
Composite can shrink and the bonding agent is humidity sensitive (need rubber dam)
Black’s III - treatment material? how to identify? access cavity?
Difficult to spot
Access from palatal
Restored with composite
Black’s IV - treatment material? occlusion?
Involve anterior guidance
Composite/Glass ionomer
Black’s V - treatment material? site?
Composite
At the cervical margin
Basics of cavity preparation? (5p)
Access caries via outline form Small as possible Remove caries (mechanical and chem) Complete prep (fill, function, tidy and clean) Restore and maintain
Correcting enamel margins - why they are a problem? solution?
Unsupported enamel is weak and can fracture
Thin restorations can fracture
Bevel to increase SA for bonding
Cavity preparation - enamel, dentine and restoration? (what to do during each stage)
Enamel:
- gain access ‘outline form’
- remove unsupported prims and demineralised margins
- high speed with TC/diamond bur
Dentine:
- remove soft wet caries dentine
- identify peripheries
- excavate peripherally then towards pulp
- hand excavator and slow speed TC/steel rosehead
What material to use and if there is any further carious dentine remaining
Angles formed for cavity preparation?
Line angle where 2 lines meet
Cavosurface angle where cavity wall meets tooth surface should be between 90-110
Point angle where 3 or more lines meet
Cavo-surface angles - difference between amalgam and composite?
Amalgam:
- ideally 90
Composite:
- less than 90 with bevel
Cavity modification once the carious lesion has been removed - what to think about?
Improve retention
Cavity support
Improve material function
Retention techniques of cavity preparation - types? how they’re formed?
Physical:
- make small grooves so restorative material is added and locks into place
Chemical:
- acid etch and bond
Cavity structural terms to know - occlusal floor, gingival floor, isthmus, proximal box and pulpo-axial wall
Occlusal floor - base of cavity
Gingival floor - floor of cavity near gingiva
Isthmus - connecting piece of cavity from one area to another, needs to be narrow to keep strong
Proximal box - box prepared for access to caries interproximally
Pulpo-axial wall - side wall of cavity that runs along the pulpal wall
Internal cavity preparation features - what to avoid and what to aim for?
Avoid sharp line angles
Aim for rounded angles to reduce stresses
Minimally invasive technique
Key structural components to preserve when cutting cavities?
Preserve oblique ridges (transverse ridge joining the BD triangular ridge and the distal cusp ridge of the ML cusp) in max molars
Marginal ridges in anterior and premolar teeth
Restorational failure - new disease? trauma? technical failure?
New disease:
- secondary caries (poor margins)
- heavily restored can lead to pulpal inflamm
- pulpal necrosis
Trauma:
- contact sport
Technical failure:
- fractured restorations (2nd caries or fault in prep)
- tooth fracture (weakened tooth or poor margins)
- appearance (wrong shade, shape, aesthetic and staining)
Cervical caries - where are they? why they occur? treatment? risk? when to intervene? cavity design? clinical technique for placement (process and problems assoc)?
Where:
- top of the teeth right at the gingival margin
Why:
- missed by brushing and a plaque retentive factor
Treatment:
- high caries risk and treated accordingly (OHI)
Intervene:
- painful, pulp threatened, poor aesthetics and hinder plaque control
Design:
- limited to carious tissue (no extra retention needed)
Tech:
- rubber dam for retraction and isolation
- remove caries minimal
- etch, prime and bind then place composite
- problems such as access, moisture control and use of composite for morphology
Root surface caries - common with? why form? rate? primary? secondary formation (cause)? risk factors? treatment (OH and restorations)? rehydration tips (examples of products)?
Common: - with older generation Why: - gingival recession Rate: - spread into dentine Primary: - lesion on root surface (no enamel involvement) Secondary: - due to an existing restoration Risk: - xerostomia - repeated carbs - partial denture - poor OH - high caries experience - high bacteria Treatment: - OHI, F therapy (higher PPM, gel and varnishes) dietary advice and regular appointments - shallow; if cleansable can be left - deeper; remove caries restore with GIC for fluoride (moisture control) (hand excavate) Rehydration: - vaseline - atomisers - biotene - gum - sip water
Cervical caries - location? age group? cause?
Location: - closest to the gingival margin Age group: - younger patients - elderly (following root) Causes: - Poor OH - orthodontic treatment
Root caries - located? caused by? increase in prevalence why? treatment (silver diamine F - contraindications, MoA?)
Located:
- caries on the root surface below ACJ
Caused:
- due to root surface exposure following perio support loss
Increase:
- ageing
- retaining teeth
Treatment:
- silver diamine fluoride; stops cavity development, more effective than F varnish
- stains black
- contraindicated with silver allergy, exposed pulp, oral ulcer, sores or advanced perio
- MoA: antibacterial, preserve collagen degrad and reacts with Ca2 and PO4 to produce FHA
Root caries treatment - biotene? Arg-based paste? ACP-CCP (adv and MoA)?
Biotene: - toothpaste, gel and spray Arg-based paste: - most toothpastes ACP CCP: - good for remineral and sensitivity - MoA: supply Ca, PO4 and F to drive diffusion of ions into tooth - formation of hydroxyapatite
Non-carious tooth surface loss - definition? types of loss?
Definition: - irreversible loss of hard tooth structure caused by factors other than those responsible for dental caries Types: - erosion - abfraction - abrasion - attrition
Erosion - clinical appearance? common imperfections? causes? intrinsic acid (examples and conditions)? extrinsic acid (examples and conditions)? common surface? Bulimia (CS?) management of erosion?
Appearance: - any surface, smooth and polished - shallow depression can occur Common: - chipping of incisal edges - cupping of lower molar cusps Causes: - substances which dissolve teeth (lower than 5.5pH) Intrinsic: - acid from within the body - reflux: alcohol, stress reflux and gastric ulcer - vomiting: bulimia, drugs, preg and rumination Surface: - palatally of upper and occlusal of lower molars Bulimia: CS - teeth marks on fingers - malnutrition and dehydration - lesions on palate Extrinsic acid: - acid external to the body - chlorinated water Management: - basic erosion wear examination (4 point scale - 0 - non, 1 - initial loss of surface texture, 2 - distinct loss <50% and 3 - >50% tissue loss) - cumulative score across all sextants (none 0-2, low 3-8, med 9-13 and high 14) - prevent further with fluoride
Abrasion - definition? cervical? habitual? iatrogenic (abrasiveness)?
Definition:
- process of scraping or wearing something away
- an abnormal wearing away of the tooth substance by causes other than mastication
Cervical:
- horizontal brushing
- hard toothpaste and brush
Habitual:
- pipe, wind instruments, pins and grips
Iatrogenic:
- dental treatment
- abrasive dental materials (most porcelain and least is resin)
Attrition - definition? physiological (surfaces?) pathological (differences? cause?) bruxism - definition? assoc signs, symptoms and management?
Definition:
- loss of tooth substance or of a restoration as a result of mastication or of occlusal or proximal contact between teeth
Physiological:
- increases with ageing
- affects occlusal surfaces or incisal edges
- also proximal surfaces due to mastication
Pathological:
- loss at a greater rate than with ageing
- caused by parafunction, malalignment or premature loss of teeth
Bruxism:
- involved in grinding and clenching teeth
- stress
- signs: TMJ pain, muscle tenderness and hypertrophy of masticatory muscles
- management: manage cause and teeth shield
Trauma - enamel fracture? dentine fracture?
Enamel fracture: - loss of enamel - radiographic evidence - restoration Enamel dentine fracture: - loss of enamel and dentine - TTP - radiographic evidence - close to pulp give it a base CaOH - restoration
Abfraction - definition?
Definition:
- pathological loss of hard tooth substance caused by biomechanical loading forces
- such loss is thought to be due to flexure and chemical fatigue degrad of enamel and dentine at some location distant from the actual point of loading
Clinical examination - patient complaint (identify injury? pain information? appearance? dental? medical? social history?) dietary analysis?
Identify: - when, what, where, why and how Pain: - site, onset, character, radiates, assoc symptoms, timeline, exacerbating or relieving factors and severity Appearance: - discoloured Dental: - brushing habit, brush type, paste, freq and treatment Medical: - reflux or sick Social: - alcohol, drug, sport and stress Diet: - identify acidic foods
Refurbish and repair - why can it be better than replacement? definitions of review? refurb? reseal? repair? replace? clinical indications for repair?
Better: - tooth weakening - repeated insult to pulp - pulp death - time/cost and tolerance Review: - minor defects only if not plaque retentive Refurb: - small defects Reseal: - using flowable - seal defects Repair: - addition to a restoration removal or mod of part of the restoration Replace: - complete removal and replacement Clinical indications: - secondary caries - marginal defects - colour corrections - bulk fracture - adj tooth fracture - wear
Repair - secondary caries treatment? staining treatment? contraindications for repair?
Treat as new lesion Secondary: - minimally invasive coupled with partial replacement - remove any part of restoration that is undermined or hindered - leave sound restoration Staining: - polishing and refinishing - resurface with different shade Contraindications: - high caries risk - history of failure - patient reluctance - irregular attender - caries that undermines most of the restoration
