Purpose: This study was conducted to expand the knowledge on the incidence of
complete cusp fractures of posterior teeth in Dutch general practices. Materials and
Methods: During a 3-month period, data were obtained from 28 general practitioners,
representing 46,394 patients. For each new case of complete cusp fracture, clinicians
recorded information using a standard form with questions relating to location of the
fracture, cause of fracture, and restorative status of the tooth prior to the cusp fracture.
Results: There were 238 cases of complete cusp fracture recorded. The results of this study
indicate an incidence rate of cusp fractures of 20.5 per 1,000 person-years at risk. Molars
were more frequently registered with cusp fractures than premolars (79% vs 21%).
Maxillary molars presented more fractures of buccal cusps (66% vs 34%), while
mandibular molars presented more fractures of lingual cusps (75% vs 25%). Almost 77%
of the cases had been restored on three or more surfaces. Statistical analysis revealed a
positive correlation between history of endodontic treatment and subgingival fracture
location. Mastication was most frequently reported as the cause for fracture (54%),
although one can argue whether the occlusal force was the cause or the immediate reason.
Conclusion: This study revealed that complete cusp fracture is a common phenomenon in
dental practice and has shown differences in cusp fracture with respect to tooth type and
restorative status of the tooth. Teeth with a history of endodontic treatment are susceptible
to unfavorable subgingival fracture locations.