Tooth wear.pdf

Oral diagnosis and treatment planning: part 4. Non-carious tooth surface loss and assessment of risk Non-carious tooth surface loss or tooth wear is becoming an increasingly significant factor affecting the long-term health of the dentition. The adverse effects of tooth wear are becoming increasingly...

Oral diagnosis and treatment planning: part 4. Non-carious tooth surface loss and assessment of risk Non-carious tooth surface loss or tooth wear is becoming an increasingly significant factor affecting the long-term health of the dentition. The adverse effects of tooth wear are becoming increasingly apparent both in young persons and, as more people retain their teeth, into old age. This situation challenges the preventive and restorative skills of dental practitioners. It has been well-documented that the main mechanisms of clinical tooth surface loss (TSL) or tooth wear are erosion (corrosion), attrition, and abrasion. Co-factors such as hyposalivation and hypomineralisation of the teeth may exacerbate the effects of the primary cause. TSL may result in widespread exposure of dentine with hypersensitivity, an unsightly appearance of the teeth and reduced masticatory function. The basic clinical approach should be as follows (to diagnose and manage TSL): - Identify the mechanism(s) causing the wear (attrition, abrasion, erosion or combinations thereof) - Determine if the evident mechanism(s) is active - Identify why the patient has this problem(s) and then tailor-make a preventive and monitoring program that is specific for the patient - Where an operative approach is required, minimum intervention requiring the preservation of tooth structure is essential. The patient should be made aware of the consequences if nothing is done, both in terms of dental damage and eventual cost, versus the advantage of preventive action and its benefits. EROSION (Background knowledge): Erosion (corrosion) is the chemical dissolution of tooth sub-stance without the presence of dental plaque. Comparison between The acid of the plaque and the Acid causing erosion: * Plaque has weak acids that act over relatively long periods (15-20 minutes). The slow percolation of plaque acids within the laminar pores of enamel rods produces subsurface demineralization with the characteristic carious ‘white spot’ lesion * Acids causing erosion are moderate (~ pH = 5) to strong (pH = 1.2) acids that act on tooth surfaces over short periods (15-60 seconds). This acidity act much faster affecting only the tooth surface with very little subsurface damage. The sources of acids that cause tooth erosion originate either from - Inside the body as gastric acid (intrinsic or endogenous erosion) - Outside the body as dietary, environmental or occupational acids (extrinsic / exogenous erosion Factors affecting the severity: - Source of acid (intrinsic, extrinsic) - Frequency of exposure The general erosive patterns observed clinically are as follows: Vomiting: generally, the palatal surfaces of all the maxillary teeth are affected most because the tongue usually covers the mandibular teeth during vomiting. Immediately after the episode, gravity and the actions of the cheeks and lips during swallowing will distribute the vomitus residue to other parts of the mouth including the mandibular arch until, over time, most of the tooth surfaces are affected 1 of 6 Gastro-oesophageal reflux disease (GORD): the refluxate rises to the back of the throat and soft palate. Usually, the palatal surfaces of the maxillary posterior teeth are affected Rumination, where the refluxate enters the mouth and is chewed, has been noted among bulimics and infants. Here the erosive pattern is more generalized and, in particular, includes the occlusal tooth surfaces Eructation (burping) where moist ‘acidic air’ enters the oral cavity also will have an effect. Though the palatal surfaces of the maxillary teeth are generally involved, other surfaces certainly can be affected depending whether the mouth is opened or closed during the burping action Dietary: - the occlusal surfaces of the mandibular teeth are affected more than the maxillary teeth, then the agent is usually a liquid that floods the mandibular teeth. - If the occlusal surfaces of both arches are equally affected, then the agent is usually solid acidic food that is masticated More importantly, liquids of low pH and high titratable acid also affect the palatal surfaces of the maxillary anterior and premolar teeth (Table 1). The action of swallowing affect the palatal surfaces of the maxillary teeth. Affected palatal surfaces of the maxillary anterior teeth are caused only by intrinsic acid Habits that can cause / Prevent erosion: - Drinking directly from a bottle or from a glass also produce erosion variations (labial anteriors). - Using straw can prevents the labial surfaces of the anterior teeth being eroded. - Swishing acidic drinks before swallowing may erode multiple posterior tooth surfaces, - Sucking citrus fruits also may affect the labial surfaces of the anterior teeth. - Acidic sour-sweets or candies used by kids Identifying erosion - The teeth lose their micro-anatomical enamel and develop a ‘glazed’ or ‘silky’ appearance. - Then teeth lose their normal contours -> flatten become ‘dished-out’ (buccal & labial) - Then the severity of the ‘scooping’ or ‘cupping’ increases significantly, often leaving high enamel ridges surrounding the dentine. - Presence of non-carious cervical lesions (including wedge-shaped lesions) should also indicate to practitioners the activity of erosion. wedge-shaped lesions, caused by: - Abfraction (the flexing of teeth under load leading to non-carious cervical lesions) - Toothbrush/ dentifrice abrasion and, in particular, erosion Identify activity - Enamel surfaces that appear ‘glazed’ or ‘silky’ - Active erosion remove the surface smear layer from exposed dentine, opening the dentinal tubules and causing dentine hypersensitivity - If the dentition shows no evidence of plaque then this is evidence of high erosive activity, as long exposure to acids remove any evidence of biofilms. - Activity can be determined using either: - a ‘scratch test’ over a short time period, - Serial colour photographs ( compare enamel translucency & shade) - High-quality dental casts ( compare changes in tooth morphology) 2 of 6 Identify contributing factors specific to the patient: - The identification directs the clinician towards eliminating the aetiological agent(s) - A reduced quality and quantity of saliva are important contributing factors. - Xerostomia (the sensation of dry mouth) or varying degrees of hyposalivation, - Medications that cause hyposalivation need to be identified, - The age of the patient also should be considered. - Newly erupted teeth have enamel crystals containing high amounts of carbonated hydroxyapatite that will dissolve more readily in acids than ‘matured’ enamel, which has a higher percentage of fluorapatite and other minerals - Past and present fluoride experience must be considered as another risk factor. Prevention (should be specific for that patient): - The most important factor is identifying and eliminate the acidic aetiological agent(s) - Examples: - Dietary soft drink, a wine or consumed food such as pickled vegetables. - GORD may require confirmation/intervention by referral to a medical practitioner - Rinsing with water during known times of acid exposure, such as after a bulimic episode - Various remineralizing products such as fluorides and casein-derived pastes containing Recaldent (CPP-ACP: casein phosphopeptide-amorphous calcium phosphate) What to use in such cases: - Fluoridated mouth rinses 3 times daily - Small “bead” of toothpaste on the tongue and spreading it through the mouth rinsing it - 1.23% Acidulated phosphate fluoride: ions for remineralization derived from tooth surface - Stannous fluoride: form a protective barrier to acids - The CPP-ACP complexes incorporate fluoride ions to form CPP-ACFP. - smeared over the teeth before bedtime (who has hyposalivation and nocturnal gastric reflux) - Recaldent products Recaldent - Causes remineralisation - Effective when the pH drops - Causing the protein (CPP) to release the calcium and phosphate ions at the time of need. - Act as an artificial pellicle allowing the Ca and phosphate ions to be released as soon as the pH drops Attrition Attrition is the wear that occurs from tooth-to-tooth contact without the presence of food. - The main risk factors is either chronic ‘stress’ or ‘distress’ seem. Therefore, tooth grinding behavior can be considered as physiologic, depending on life events. - The grinding stroke is from centric occlusion (maximum intercuspal position) to eccentric lateral positions. Movement past the canine edge to edge position. - Can cause enamel flaking (labial of upper incisal edge, and mandibular anterior edge) - Also can affect Buccal cusps of maxilary and mandibular cusps of mandibular posteriors - Common feature is FACETS. Usually have a matching facet on the opposing arch Facets: a relatively flat area with a well-circumscribed border 3 of 6 Identifying attrition Presence of facets Enamel flaking and cusp fractures Symptoms of various craniomandibular disorders. Identify activity Can be determined using the scratch test Well-demarcated tooth facets are present, even when other TSL mechanisms coexist Shiny facets (indicates high activity) Flaked enamel on the incisor teeth is not stained (flaking has happened recently —> active) Patient has been aware of tooth grinding (active) Symptoms of myofascial pain dysfunction with associated limitation of jaw opening (active). Identify contributing factors specific to the patient - Chronic stress, whether it is related to lifestyle, personality trait, or various mental disorders, appears to be the common denominator for active tooth grinding - Iatrogenic occlusal interferences that are suddenly introduced into the system become obstacles to an already developed pattern. - Some craniofacial types —> Angle Class II division 2 malocclusions with deep anterior overbites tend to result in excessive anterior tooth wear, while the posterior teeth remain relatively unaffected. Prevention (should be specific for that patient): - Acrylic resin nightguard/splint (prevent opposing tooth contacts, hence reduce their rate of wear) - Stress management or appropriate referral for psychological assessment - Mousse Crème as a lubricant over occlusal enamel and dentine surfaces ABRASION Abrasion is the wear that occurs by the friction of exogenous material (anything foreign to the tooth) that is forced over the surfaces of the tooth. The most common form of abrasion is that produced by food. Abrasion from food is comparatively minimal now a-days, it often coexists with erosion, which produces an increased wear rate. This wear is often called ‘erosive tooth wear’ The wear from food abrasion is generally distributed throughout the arch and, when dentine is exposed, it is scooped out because it is softer than enamel. Interestingly, such exposures show no sensitivity because the dentinal tubules are covered by a smear layer resulting from mechanical friction between the teeth and food. Examples: - Eating hard foods such as nuts and seeds may cause abrasion on specific tooth surfaces. - Occupational habits such as holding hairdresser bobby pins or hairpins between the incisors. - Dusty working environments, which occur in iron-works, mines and quarries, may lead to increased tooth abrasion. - Microwear detail of non-carious cervical lesions show evidence of abrasive wear from the toothbrush/ dentifrice used (though evidence of superimposed erosion also has been reported). - Using interdental wooden toothsticks —> abrasive wear of the adjacent proximal root surfaces. 4 of 6 Identifying abrasion - Foreign objects such as tobacco pipe stems and bobby hairpins, or from hard foods such as watermelon and pumpkin seeds (passively nibbled incisally on the anterior teeth) - Asymmetric wear in the form of a ‘notch’ on the anterior teeth - Scooped dentine on the incisal and occlusal surfaces, if the exposed dentine is not sensitive - A wedge-shaped non-carious cervical lesion is a strong indication that toothbrush/ dentifrice abrasion is an aetiological factor though Identify activity - Identifying abrasion is difficult because of the common contributing effect of erosion. - History taken to show a continuing habit, such as the continual use of a pipe —> active - Serial colour photographs or dental casts can show a progression in wear. Identify contributing factors specific to the patient - A history showing the frequent consumption of abrasive foods such as nuts and seeds - Erosion may be a contributing factor. - Newly primary erupted teeth that have not ‘matured’ may be more prone to abrasion - Excessively loaded anterior teeth will wear faster when there are edentulous posterior segments from previous extractions. Prevention (should be tailor-made specific for that patient): - Taking history to identify abrasive dentifrices, foods, foreign objects, or common habits that are causing the problem - Making the patient aware of the problem and taking responsibility can have a profoundly positive effect - Restore a full complement of occluding teeth will allow a better distribution of load and hence a reduction of occlusal abrasion. RESTORATION WEAR - Restorative materials are subject to the same wear processes as tooth structure, - The lowest antagonistic wear rates appear to occur with amalgam and cast metal alloys, microfilled and nanofilled resin composites, and machined ceramics. - Conventional GIC and RMGIC are more susceptible clinically to abrasive and erosive wear than other restorative materials. - Severe hyposalivation may exacerbate the effects of erosion. - The surfaces of ceramic and resin composite materials that contain glass particles are susceptible to damage from acidulated fluoride gels. ASSESSMENT OF RISK TO TOOTH SURFACE LOSS - The basic erosive wear examination (BEWE) index provides some clinical guidance for the risk assessment and management of tooth erosion. MONITORING TOOTH WEAR - Once a preventive approach is implemented, follow-up assessments should be made to see if the measures undertaken are successful. - Monitoring requires a complete reassessment where the history, special tests, colour photographs and dental casts are repeated, to note either improvement or otherwise from the original assessment. 5 of 6 6 of 6