Actuarial life-table analysis of lower impacted wisdom teeth in general dental practice.

BACKGROUND: The appropriateness of extraction of asymptomatic impacted third molars has been much debated and as a result the number of extractions has fallen in the UK in the past few years. As a direct consequence of this decrease more impacted third molars are left in situ and yet, little is known about the natural history of these teeth. OBJECTIVE: The aim of this study was to create an actuarial life-table and related survival analysis that would shed light on the natural history of an impacted lower third molar. METHODS: Panoramic radiographs taken in 14 different general dental practices in Scotland were analysed and matched with their respective case notes in order to generate a sample of patients with asymptomatic impacted lower third molars. Subjects were assessed to confirm the presence of impaction and absence of symptoms and then re-assessed 1 year later for the development of symptoms during the study period to relate the incidence of symptoms within 1 year in the sample studied to age. Logistic regression was used to construct a life table based on the survival of symptom-free teeth (independently of extraction) during the study period. RESULTS: The number of patients included in the study was 583 and 421 for the baseline and follow-up assessments respectively. The total number of teeth analysed in both appointments was 676; from those 37 (5.47%) were extracted during the study period. About 562 teeth (83.13%) survived the study period symptom-free. There was a statistically significant inverse association between the development of symptoms studied and age. There was no statistically significant association between extraction and age. CONCLUSIONS: The study indicates that older patients are less likely to develop the symptoms studied. In addition the authors believe that there is evidence to suggest that general dental practitioners might not be following current guidelines when deciding whether or not to extract an impacted lower third molar in the centres studied.

Assessing oral health-related quality of life in general dental practice in Scotland: validation of the OHIP-14.

OBJECTIVES: To validate the Oral Health Impact Profile (OHIP)-14 in a sample of patients attending general dental practice. METHODS: Patients with pathology-free impacted wisdom teeth were recruited from six general dental practices in Tayside, Scotland, and followed for a year to assess the development of problems related to impaction. The OHIP-14 was completed at baseline and at 1-year follow-up, and analysed using three different scoring methods: a summary score, a weighted and standardized score and the total number of problems reported. Instrument reliability was measured by assessing internal consistency and test-retest reliability. Construct validity was assessed using a number of variables. Linear regression was then used to model the relationship between OHIP-14 and all significantly correlated variables. Responsiveness was measured using the standardized response mean (SRM). Adjusted R(2)s and SRMs were calculated for each of the three scoring methods. Estimates for the differences between adjusted R(2)s and the differences between SRMs were obtained with 95% confidence intervals. RESULTS: A total of 278 and 169 patients completed the questionnaire at baseline and follow-up, respectively. Reliability - Cronbach's alpha coefficients ranged from 0.30 to 0.75. Alpha coefficients for all 14 items were 0.88 and 0.87 for baseline and follow-up, respectively. Test-retest coefficients ranged from 0.72 to 0.78. Validity - OHIP-14 scores were significantly correlated with number of teeth, education, main activity, the use of mouthwash, frequency of seeing a dentist, the reason for the last dental appointment, smoking, alcohol intake, pain and symptoms. Adjusted R(2)s ranged from 0.123 to 0.202 and there were no statistically significant differences between those for the three different scoring methods. Responsiveness - The SRMs ranged from 0.37 to 0.56 and there was a statistically significant difference between the summary scores method and the total number of problems method for symptomatic patients. CONCLUSIONS: The OHIP-14 is a valid and reliable measure of oral health-related quality of life in general dental practice and is responsive to third molar clinical change. The summary score method demonstrated performance as good as, or better than, the other methods studied.