Introduction
The aim of this study was to investigate the prevalence of tooth wear in adolescents with Class II malocclusion, compared with those with normal occlusion.
Methods
The sample consisted of dental casts obtained from 310 subjects, divided into 3 groups: group 1, 110 subjects with normal occlusion (mean age, 13.51 years); group 2, 100 complete Class II Division 1 patients (mean age, 13.44 years); and group 3, 100 half-cusp Class II Division 1 patients (mean age, 13.17 years). Dental wear was assessed by using a modified version of the tooth-wear index. The 3 groups were compared by means of the Kruskal-Wallis and Dunn tests, considering the frequency and the severity of wear on each surface of each group of teeth. The level of statistical significance was set at 5%.
Results
The normal occlusion group had statistically greater tooth wear on the palatal surfaces of the maxillary central incisors and the incisal surfaces of the maxillary canines than the corresponding surfaces in both Class II malocclusion groups. The complete and half-cusp Class II Division 1 malocclusion groups had statistically greater tooth wear on the occlusal surfaces of the maxillary second premolar and first molar, the occlusal surfaces of the mandibular premolars, and the buccal surfaces of the mandibular posterior teeth compared with the normal occlusion group. The half-cusp Class II Division 1 malocclusion group had significantly greater tooth wear on the incisal surfaces of the mandibular incisors compared with the complete Class II Division 1 malocclusion group.
Conclusions
Subjects with normal occlusion and complete or half-cusp Class II Division 1 malocclusions have different tooth-wear patterns. Tooth wear on the malocclusion subjects should not be considered pathologic but, rather, consequent to the different interocclusal tooth arrangement.
Editor’s summary
Tooth wear from erosion, abrasion, and attrition has long been a concern to dentists. Some wear is normal throughout life. Some studies indicate that masticatory forces and malocclusion are the primary etiologic factors for additional wear, but others did not find this correlation. The aims of this study, from universities in São Paulo, Brazil, and Toronto, Ontario, Canada, were to compare patterns of tooth wear in subjects with complete and half-cusp Class II Division 1 malocclusions and normal occlusion.
The sample consisted of dental casts from 310 untreated adolescents in 3 groups: 110 with normal occlusion, 100 with complete Class II Division 1 malocclusion, and 100 with half-cusp Class II Division 1 malocclusion. Additional inclusion criteria were no parafunctional habits, no temporomandibular or airway problems, and no open bites. Read this entire article online for details of the techniques used to measure wear facets by a calibrated examiner.
Overall, 22,320 dental surfaces were evaluated, and 73.9% showed no dental wear. Interestingly, the normal occlusion group had statistically greater tooth wear on the palatal surfaces of the maxillary central incisors and the incisal edges of the maxillary canines. Although some reports in the literature have suggested an association between increased tooth wear and malocclusion, others did not corroborate this premise. It was concluded that subjects with normal occlusion and complete or half-cusp Class II Division 1 malocclusions have different tooth-wear patterns. Wear in the malocclusion subjects should not be considered pathologic but, rather, a consequence of the different interocclusal arrangement of the teeth.
These researchers plan to pursue future studies of older patients; it will be interesting to see the influence of differing interocclusal relationships.
