Grippo JO. Abfractions: a new classification of hard tissue lesions of teeth. J Esthet Dent. 1991; 3:14-19
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Milosevic A. Tooth wear; an aetiological and diagnostic problem. Eur J Prosthodont Rest Dent. 1993; 1:173-178
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Bachanek T, Chalas R, Pawlowicz A, Tarezydto B. Exposure to flour dust and the level of abrasion of hard tooth tissues among the workers of flour mills. Ann Agric Environ Med. 1999; 6:147-149
Djemal S, Darbar UR, Hemmings KW. Case report: tooth wear associated with an unusual habit. Eur J Prosthodont Rest Dent. 1998; 6:29-32
Paterson AJ, Watson IB. Case report: prolonged match chewing: an unusual case of tooth wear. Eur J Prosthodont Rest Dent. 1995; 3:131-134
Fitton JS. A tooth ablation custom occurring in the Maldives. Br Dent J. 1993; 175:299-300
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Tooth surface loss (TSL), the non-carious loss of tooth tissue, is considered pathological if the teeth involved experience sensitivity and pain, are functionally compromised or they detract from the patient's appearance. TSL is a common clinical finding in many patient groups, although differences between the primary and permanent dentition contribute to TSL occurring at a faster rate and with worse outcomes in the primary dentition. This case report presents localized abrasion and associated apical periodontitis affecting a single primary tooth in a 2-year-old infant following the misuse of a babies' dummy clip whilst teething. Abrasion is rare in the primary dentition.
CPD/Clinical Relevance: This article highlights an unusual presentation of dental abrasion affecting the primary dentition caused by a previously unreported foreign object; abrasion in this case was a side-effect of soothing the discomfort of teething.
Article
Tooth surface loss (TSL) is the non-carious loss of tooth tissue that occurs throughout life1 that is generally multifactorial in nature. Factors causing TSL include:
TSL is generally regarded as pathological if teeth become so worn that they do not function effectively, become a source of pain or seriously compromise appearance.3 It has been suggested that the term TSL be used when it is not possible to identify a single aetiological factor responsible for the wear.3Attrition is a physiological phenomenon where tooth substance is removed following contact between opposing dental surfaces.3Erosion is a chemical process involving the loss of tooth substance, usually following contact with acid of either intrinsic or extrinsic origin.3Abrasion involves wearing away of tooth substance by the repeated friction of a foreign body against the tooth, independent of occlusion.4 Grippo5, who introduced the term abfraction, defined it as the pathologic loss of dental hard tissue as a result of biomechanical loading forces that results in flexure and eventual material fatigue of susceptible teeth at locations distant from the loading region. Resorption of dental hard tissue can be a physiological or pathological process that involves clastic activity.2 Wearing away of tooth substance in the course of chewing of food is termed demastication and this depends on the abrasiveness of the food.2
Children most frequently present with attrition affecting their incisal edges and this is noted in the late primary dentition stage; abrasion is considered uncommon6 however, when present, it is frequently the result of toothbrushing.7
Abrasion may have varied presentations according to the external physical agent implicated; the different appearances can be associated with dental hygiene devices, certain occupations, habits and cultural/ritualistic practices.
Dental hygiene devices
Firm, incorrect toothbrushing in the horizontal plane, instead of using the modified Bass method, can cause wedge-shaped defects in the cervical regions of predominantly maxillary teeth.3,4,8 Brushing teeth with an abrasive dentifrice, such as sodium bicarbonate powder, or use of meswak (wooden toothbrush) can cause labial abrasion.3,9 Approximal abrasion of exposed root surfaces has been reported following the use of toothpicks and dental floss.9,10
Occupational abrasion
Holding/opening of bobby pins by ladies' hairdressers can present as notching of incisal edges.3,4 Cobblers and seamstresses who hold nails, needles, pins or pass thread between their teeth can have chipping or notching of the incisal edges of their anterior teeth.4,11 Flour millers experience dental abrasion following inhalation of flour dust. A study in Poland demonstrated the prevalence of abrasion correlating with the number of years an individual has worked in a mill plant and that incisors were the most frequently damaged teeth.12
Habits
Splitting of roasted sunflower, pumpkin or watermelon seeds, such as by people of Mediterranean/Middle-Eastern extraction can result in triangular-shaped abrasion lesions involving the incisors.9 Pipe-smokers may develop extensive wear of their anterior teeth in the region where the pipe-stem is held.3,4,11 The literature also records individuals who have practised unusual habits that result in bizarre abrasion lesions. One 36-year-old female presented with extensive abrasive lesions affecting the majority of her teeth; she was found to have a 20-year habit of chewing and swallowing sand which allegedly helped her to relax.13 A 48-year-old housewife who suffered from an obsessional neurosis was found to have extensive abrasion lesions due to a 5-year habit of chewing 1–2 packets of matches per day.14
Abrasion related to cultural/ritual practices (also known as tooth ablation or mutilation)
The term ‘tooth ablation’ was coined by Fitton15 to describe the religious, ritualistic, tribal or decorative/aesthetic alterations made to the dentition. Ablation may consist of direct chipping or filing of teeth through to placement of gold, jade or turquoise as inlays, or indirect changes as a result of external factors such as labrets; these have been used by Inuit in North America down to peoples in Central America and noted to produce smooth, polished labial surfaces of the teeth against which they continuously move.16 Such cultural and ritualistic practices are reported to have been widespread during the Iron Age (300–900 AD) in places such as the African continent,17 as well as the Americas,18 though have gradually decreased with time, largely attributed to the contact of indigenous people with Spanish Conquistadors in the Americas, or Western Colonialists in Africa. One modern example of tooth ablation may be seen in the Maldives where the incisal edges of the maxillary anterior teeth are ground with a knife-sharpening stone so that those teeth lie in a straight line.15 Such an appearance is deemed by members of that particular society to be dentally attractive.
Primary teeth have several important structural differences from permanent teeth that leaves them more susceptible to insults and thus their response differs compared with their permanent counterparts; they are likely to be more vulnerable to TSL and its sequelae. They are smaller, more permeable and easily worn down compared to permanent teeth.19,20 Their enamel is thinner20 and softer, having a reduced surface microhardness.21 Primary dentine is also thinner and more permeable,22 containing dentinal tubules of larger diameter that are greater in density.23 Furthermore, primary teeth have relatively larger coronal pulps and more prominent pulp horns when compared with permanent teeth.19,20 Pulp vitality is normally protected by tertiary dentine deposition beneath the site of injury, however, if the rate of wear and its degree are severe, pulpal necrosis can occur.11
Case report
A two–year-old (27 months) girl was referred to the Eastman Dental Hospital by her general dental practitioner (GDP) for investigation and management of her upper left central primary incisor (ULA) which had an abscess.
She attended with her parents, was medically fit and well; the presenting complaints included the presence of a dental abscess along with the same tooth (ULA) having become grey in colour and the edge being chipped. The abscess was first noticed two weeks prior to the appointment in clinic; this was the trigger for the initial appointment with the GDP. There was no history of any acute traumatic episode or acute pain, however, she was avoiding incising with the affected tooth. The mother recalled a gradual wear of the tooth; a chip on the incisal edge was first noticed when the child was nine months old.
An extra-oral examination did not detect any abnormalities. Intra-orally she presented with a full primary dentition and good level of oral hygiene. An unusual pattern of wear, confined solely to the ULA, in the form of a smooth notch on the incisal edge extending into dentine was noted. The tooth was mildly discoloured grey in its appearance compared with the adjacent teeth and presented with an associated granulomatous discharging sinus tract on the labial gingivae (Figure 1a).
Figure 1. Features observed at examination. (a) Abrasion on the upper left primary central incisor tooth (ULA) in the form of a notch and granulomatous sinus tract on the labial gingivae. (b) Upper standard occlusal radiograph demonstrating incomplete apex of the upper left primary central incisor tooth (ULA) with apical radiolucency.
The tooth was slightly tender to gentle finger pressure; mobility was within normal limits. Pulp testing gave a negative result whilst radiographic examination demonstrated an incomplete root with an associated radiolucency; the notch did not directly involve the pulp (Figure 1b).
On further questioning, the parents recalled that, from the time when the girl's first teeth began to erupt until recently, she would soothe her discomfort of teething by constantly rubbing her teeth on a cord component of a babies' dummy clip (Figure 2). This clip was used to fasten the dummy to her clothes so that, if the dummy fell out of the mouth, it would not be lost. The dummy clip had broken prior to the consultation and was thus discarded.
Figure 2. Example of the kind of babies' dummy clip, with dummy attached, which the infant had been using.
A diagnosis of chronic apical periodontitis due to chronic abrasive trauma was made and arrangements made for extraction of the tooth. Extraction under local anaesthesia was attempted but the girl was unable to give full co-operation. Eventually, the tooth was extracted, intact, under a general anaesthetic, eight days following her initial consultation in clinic (Figure 3). Upon discharge, her parents were advised to maintain recall appointments with their GDP who would be able to provide follow-up care, monitor the girl's dental health and development, and refer her for interceptive treatment if and when indicated.
Figure 3. Upper left primary central incisor (ULA) following its extraction.
Discussion
It is generally accepted that, only when the extent of TSL exceeds physiological norms could it become problematic for the patient, who may then seek professional advice and treatment. This case report illustrates TSL of highly unusual aetiology, limited to a single primary tooth. Abrasion in children is very rare; to the best of our knowledge the literature does not record cases of abrasion affecting the primary dentition. However, cases of abrasion involving the permanent maxillary incisors have been described affecting an 11-year-old wind instrument player,24 as well as tribal filing in a 14-year-old student in Nigeria.25
The response to long-standing abrasive trauma consists of the dentine-pulp complex triggering the deposition of tertiary dentine in an attempt to protect itself by creating a distance between the pulp and the abraded dental surface. If such attempts prove unsuccessful, bacteria and their by-products infiltrate via exposed and patent dentinal tubules or via direct pulp exposure, producing pulpal inflammatory changes11 and, if allowed to progress, might result in necrosis,11,26 the classical signs of which are discoloration of the tooth, negative response to sensibility testing, tenderness to percussion and periapical radiolucency.27
As inflammation associated with periapical infection is known to compromise mineralization of the permanent tooth germ,28 that could result in enamel hypomineralization and hypoplasia or disturb the development of the permanent tooth germ,29 extraction is recommended28 and this was therefore performed; additionally, this also relieved the patient from her symptoms. Current UK National Clinical Guidelines30 do not recommend balancing or compensation extractions or fitting of a space maintainer when a primary incisor is lost; loss of a primary incisor tooth is unlikely to contribute to future centreline discrepancies.
The late presentation in this infant could be explained by her not visiting a GDP from birth, despite this recommendation in Birth to Five,31 a Department of Health publication distributed free to all mothers by health visitors shortly after the birth of a baby in the UK. Although the first sign of abrasion, an incisal chip, was noticed by the parents when the infant was 9 months old, she was taken to the GDP only on appearance of the sinus tract at age 27 months. Since infants have regular contact with healthcare professionals, such as midwives, health visitors and nurses at community baby clinics, where their health, development and growth is checked routinely, we could consider enlisting their support in not only discussing good oral hygiene habits, but also recognizing dental abnormalities and referring onwards; such action may have alerted the dental team to the abrasion in this infant at an early stage.
Conclusion
A child is dependent on its parents/carers for his or her physical, emotional and social wellbeing. This is particularly important in the case of infants who are not always able to communicate their complaints in a way for their parents/carers to understand. A child with an ailment is entirely reliant on its parents/carers to recognize the give-away signs that there is something wrong so that the child can be seen in good time by a healthcare professional for either reassurance or further investigation. A GDP should not only be able to recognize the common signs of TSL, but also be able to identify TSL attributable to unusual factors so as to implement appropriate treatment planning and management, including preventive strategies, where necessary. The premature loss of a primary tooth may impact on a child's quality of life potentially affecting his or her appearance, speech and masticatory ability. Hospital admissions for dental extractions under general anaesthetic are preventable and, where possible, should be avoided as they not only have a financial burden on society but, more importantly, the psychosocial effects on a child and his or her parents can be profound.
