Paul Benjamin DMD; Kate Vig BDS, MS, FDS, Dorth
Tooth wear is a common clinical finding and increases with age from a predicted 3 percent at 20 years to 17 percent at age 70.
A review of the best available evidence indicates increased wear occurs on all teeth with age but progression longitudinally on individual teeth is unknown.
Does the prevalence of tooth wear increase with age? Does wear occur across the dentition or among specific, individual teeth?
The authors searched two electronic databases, PubMed and the Cochrane library for articles published from 1980 to 2007. They excluded non-English publications, reviews, case reports, historical and forensic studies, in vitro and in situ studies (on non-human tooth material). Articles that did not describe prevalence, studies on subjects younger than 18 years of age, and specific groups, such as alcoholics also were excluded. References were independently screened for inclusion and exclusion by two investigators. The authors used Cohen Kappa to measure agreement. Disagreements were resolved through discussion. When necessary, a third investigator mediated. Data were collected and converted into the Smith and Knight Tooth Wear Index (TWI).The authors also hand searched for relevant articles using the same criteria.
The authors selected 186 of the original 1,953 references, 13 of which satisfied the inclusion criteria. All articles reported the number of subjects, and eight articles reported the number of teeth. Four articles were suitable for regression analysis at tooth level (R2 = 0.593) and three at subject level (R2 = 0.736), using "age and age-squared" and "aged-squared" as variables, respectively. The results showed a significant level of correlation between age and tooth wear. Six studies reported males having significantly more tooth wear than females. The predicted percentage of adults with severe tooth wear increases from three percent at 20 years of age to 17 percent at 70 years of age.
Increasing levels of tooth wear are significantly associated with age. Because of the limited information from included studies, it cannot be determined if this increase reflects greater severity of wear on the same tooth or greater prevalence of wear i.e. greater number of teeth involved.
Source of Funding:
Importance and Context:
Anecdotal clinical experience suggests tooth wear is common in adults. However, there is little evidence about the natural course of this condition. Managing tooth wear is challenging because of its irreversible and multifactorial aspects. A better understanding of normal versus pathological tooth wear is needed.
Strengths and Weaknesses of the Systematic Review:
The authors used accepted methods to identify and select relevant studies on the prevalence of adult tooth wear. They may have had more studies to choose from had they not limited their search to English-only publications, and incorporated anthropology literature, as well. There were no prospective studies in the review. The authors relied on less robust cross-sectional studies, which caused them to make inferences on prevalence of wear through inspection of successive samples of increasing age. The authors did not assess study quality. They also tried to convert the original wear scores into the TWI score, which may have introduced bias towards more severe wear measurements. No conflicts of interest were noted.
Strengths and Weaknesses of the Evidence:
The study population represented 10 countries comprising more than 14,000 subjects and 170,000 teeth. There were 13 papers, from which it was possible to compare wear only on occlusal and cervical surfaces. The authors used regression models and found that the "age squared" model was the best fit. The lack of strict guidelines for quality control in the studies together with different criteria for wear indices further weakened the level of evidence. We can conclude that tooth wear increases with age, but the lack of longitudinal information limits an understanding of the natural history of tooth- or multiple-teeth wear.
Implications for Dental Practice:
The data suggest that tooth wear is common in adults, and that it increases with age. Molars were the most severely affected teeth. Incisors were the most commonly affected teeth. Males have a higher prevalence of tooth wear than females. There are no longitudinal studies that measure wear progression on the same tooth. As a result, it cannot be determined whether the increase in wear scores represents more wear on the same tooth or on greater prevalence of wear i.e. greater numbers of affected teeth. Because the condition is common, future research should investigate early preventive measures beyond the use of occlusal guards. A better understanding of causes and establishing criteria to evaluate when the condition becomes pathologic also is needed.