Causes and pattern of fracture of acrylic dentures among patients seen in a Nigerian teaching hospital.

There is little information on the causes and pattern of fracture of acrylic dentures in Nigerian patients despite being the most frequently employed design in Nigeria. The aim of this study was to determine the average life span of acrylic dentures before fracture, the causes and pattern of fracture of acrylic dentures in a Nigerian population. All consecutive patients that presented with fractured acrylic dentures at the Dental Centre, University College Hospital, Ibadan between January and July 2006 and were willing to participate were recruited into the study. A structured interviewer-administered questionnaire was used to record data from the patients. The questionnaire focused on patients' demographic data, age of acrylic denture as at the time of fracture, causes and pattern of fractures. The data were analysed using SPSS Version 11. A total of sixty-two patients were included in the study. They presented with sixty-nine fractured dentures. Five were complete dentures while 64 were partial dentures. The average life span was 7.4 years +/- 6.6 (SD) years. Early fracture was seen in 9 (13.4%), intermediate fracture in 29 (42%), and late fracture in 31 (44.9%) cases. The commonest cause of fracture was mastication as seen in 30.4% of the cases while the least cause was fight (4.3%). The commonest site of fracture (34.8%) was the palatal plate around the crest of the edentulous ridge while fracture of wrought metal clasps was the least, occurring in 1.4% of cases. We recommend proper design with balanced articulation and more emphasis on compliance to post insertion instructions by patients to prevent early fracture of acrylic dentures. Also, reinforcing the acrylic denture base especially in stress bearing area may prolong the life span of these prostheses.