The purpose of this study was to evaluate the clinical performance of preformed beta-quartz glass-ceramic insert restorations.
Nine Class I and 30 Class II beta-quartz glass-ceramic insert restorations were placed in 16 patients who were seen regularly by personnel at Umeå University Dental School. The California Dental Association criteria were used to evaluate the restorations at baseline, 6 months, and 1, 2, and 3 years after luting. The occurrence of postoperative sensitivity, the time taken to manufacture each restoration, and certain periodontal conditions were also evaluated.
Sixty-nine percent of the restorations were rated satisfactory at the 3-year examination. During the follow-up period, 4 became loose and 7 were fractured or had flaking surfaces. Caries was registered in connection with 1 restoration. Excellent ratings were obtained for marginal integrity, anatomic form, surface, and color in 62%, 84%, 32%, and 44% of the restorations, respectively. There was no statistically significant difference in the occurrence of plaque and bleeding on probing in comparison with the controls. The mean overall time for placement was 38 minutes. The estimated survival rate (Kaplan-Meier) was 59% after 3.5 years.
The quality of the beta-quartz glass-ceramic restorations in the present study was inferior to that presented in most earlier studies of ceramic or resin composite posterior restorations placed in patients treated at university clinics. Both the technique and the beta-quartz glass-ceramic inserts have to be evaluated in more long-term studies to assess the possibility of their serving as an alternative restorative technique.
The objective of the study was to examine the coverage of the sealing program on first permanent molars (FPMs) and second permanent molars (SPMs) and first and second premolars (FSPMs), as well as to monitor the fate of the sealed teeth over time. All patients born in 1977 who had had regular check-ups in the Varkaus Health Center, Finland (n = 166) were included in the 1996 study. Data on the annual state of each tooth had been collected retrospectively since 1983. The coverage for the sealant program was 95%, 92%, and 6% of the FPMs, SPMs, and FSPMs, respectively. Out of the FPMs sealed at age 6 years, 28% were subjected to resealing, 13% developed occlusal, and 15% proximal caries during a 13-year follow-up period. From the SPMs sealed at age 11 years, 24% were subjected to resealing, 4% developed occlusal caries, and less than 2% proximal caries during the 9-year follow-up. None of the sealed FSPMs and only 1% of the non-sealed ones developed occlusal caries during the 9-year period. The mean DMF in the study population (n = 160) at age 12 years was 0.8 (n = 124), compared to a nation-wide mean value of 1.2. A large percentage of the FPMs and SPMs were sealed and then resealed during the study period. Although the study design lacked a control group for comparison, the lower caries rates of this study compared to the results of other studies with only a single application of sealants suggest a major role for resealing.
A computer method enabling metric measuring in radiographs has been presented. The measurements are time saving and precise and accurate measurements can be made. The statistical analysis can be performed based on a ratio scale, allowing more reliable and conclusive statistics. The most useful field for the presented method is offered in epidemiology where great materials are being handled. Since small changes can be studied, the method can be useful in studying marginal bone level changes in large populations. Or marginal bone levels around implants. In age estimation the digitizer method has no direct valuable application during adolescence, when the lower third molar is used. Here the present series of studies showed the traditional age estimation method and the digitizer method to be fairly unprecise with rather large systematic error. The skeletal age estimation method according to Greulich and Pyle was found to be more accurate and useful during the ages 14 up to 18 years. In younger children, where more parameters or teeth are available, there may be advantages to use a digital dental method instead of a traditional dental one.
To evaluate the possibility of applying the Third Molar Eruption Predictor to all panoramic radiographs.
Panoramic radiographs were retrospectively analyzed from a 4-year follow-up study of third molars carried out at the University of Copenhagen, Denmark. The radiographs, taken at a mean age of 20.6 years, included 45 unerupted or partially erupted mandibular third molars in 28 subjects. Because the device was calibrated both with simple proportions and by use of the methods of Bayes' Decision Theory, the separation point of the device was therefore adjusted at 12 mm from the distal surface of the second molar.
The predictions of future eruption or impaction made with the calibrated device and the actual clinical outcome 4 years later were in conformity for 80% of the mandibular third molars.
The Third Molar Eruption Predictor may be applied to all panoramic radiographs, but it seems to require calibration before use.
The paper concerns the accuracy of two dental methods of age estimation based on the radiographic appearance of the root of the lower third molar. The first dental method tested was traditional with a subjective assessment of the root development stage and the second was a new method with a metric measurement of formed root length. Since previous studies have shown a relatively low precision for dentally based age estimation methods during adolescence, an additional independent indicator of chronological age was employed, namely skeletal maturity according to the atlas and method of Greulich and Pyle (Radiographic Atlas of Skeletal Development of the Hand and Wrist Stanford University Press, CA, 1959). The material was Swedish adolescents aged 12-19 years. It was found that all methods gave an overestimation of chronological age, with the highest overestimation, more than 1 year, for the two dental methods. A stepwise multiple regression analysis indicated that skeletal age alone explains 48% of the variation in estimated chronological age. It may be concluded that the accuracy of age estimations based on the lower third molars is quite uncertain during adolescence. Up to 18 years, it is preferable to use skeletal age alone as a predictor. Only a small increase in the explanation coefficient of age variation (3-4%) could be seen if digitized or subjectively estimated root lengths were added as predictors to the skeletal estimation.
In 90, 60- to 80-year-old patients with teeth retained in both jaws (mean 20.4 +/- 4.3), a total of 1,092 root surface lesions were recorded. Of these 156 were diagnosed as active caries lesions, whereas 509 were considered inactive, and 427 were filled. About 60% of the elderly had one or more active lesions and 79% had fillings. Seventy percent had more than 8 filled or carious (active or inactive) surfaces. The percentage of carious and filled root surfaces in relation to surfaces at risk demonstrated that the buccal surfaces of lower molars and premolars and upper canines were the most severely affected (RCI = 70%) with fillings predominating on easily accessible surfaces. A constant relationship between active and inactive lesions was found on all other surfaces but third molars and upper incisors. The data suggest that active and inactive root caries lesions must be diagnosed as separate entities if the dynamic nature of root surface caries is to be explored in epidemiological studies and clinical trials.
During the 1970s dentists reported an increasing prevalence of a "new" type of enamel disturbance.The disturbance was very specific, with areas of demarcated hypomineralised enamel, and was mostly found in permanent first molars and incisors. Several studies have tried to reveal the aetiology behind the enamel disturbance but sofar no clear factors correlated have been found. The aim of the present study was to evaluate aetiological factors to severe demarcated opacities (SDO) in first permanent molars in a large cohort of children enrolled in the "All Babies in Southeast Sweden" (ABIS) project. ABIS is a prospective study of all children in five Swedish counties born between Oct 1, 1997 and Oct 1, 1999, in all about 17,000 children.They have been followed from birth with recording of a large number of factors on nutrition, diseases, medication, infections, social situation etc. With help from 89 Public Dental Service clinics in the same area preliminary examinations of the children, born between Oct 1,1997 and Oct 1,1999, reported 595 children with severe demarcated opacities (SDO) in first molars.These children and a randomly selected age matched group of 1,200 children were further invited to be examined by specialists in paediatric dentistry. At these examinations 224 severe cases were identified as well as 253 children completely without enamel disturbances among children registered in ABIS.These two groups were analysed according to any correlation between SDO and variables in the ABIS databank. The analyses showed no association between SDO and pre-, peri-, and neonatal data. However, we found a positive association between SDO and breastfeeding for more than 6 months (OR 1.9; 95% CI 1.1-3.2), late introduction of gruel (OR 1.9; 95% CI 1.1-2.9), and late introduction of infant formula (OR 1.8; 95% CI 1.2-2.9). A combination of these three variables increased the risk to develop SDO by more than five times (OR 5.1; 95% CI 1.6-15.7). No significant associations were found to other environmental, developmental, or medical factors. We conclude that nutritional conditions during first 6 months of life may influence the risk to develop severe demarcated opacities in first permanent molars.
Aluminum (Al) concentration was assessed in deciduous teeth in relation to sex, year of birth, tooth type, and the presence of caries and roots. Three hundred and twenty-three deciduous teeth from children born during the period 1952 93 in a county in southeast Sweden were sampled, and the Al content determined by graphite furnace atomic absorption spectrophotometry. The arithmetic mean of the Al concentration was 0.58 +/- 0.64 ppm dry weight (mean +/- standard deviation) and differed significantly between incisors (1.05 +/- 1.04 ppm) and canines (0.48 +/- 0.50 ppm) and between incisors and molars (0.53 +/- 0.55 ppm). A significant difference was found between teeth with and without caries. No significant differences were found between sexes. The Al concentration correlated significantly with tooth weight for incisors (r = -0.47) and canines (r = -0.45) but not for molars (r = 0.03). No significant change in Al concentration was found over time. Caries-free deciduous molars are suggested as the most useful teeth for biological monitoring of aluminum.
A distance exceeding 2 mm from the cementoenamel junction (CEJ) to the alveolar bone was observed on the proximal surfaces of the first molars of proportionally more 15-year-olds (101 subjects) than 13-year-olds (99 subjects). The measurements were performed on bitewing radiographs, and the methodologic error amounted to 3%. Recordings in excess of 2 mm were most frequent (0.27 and 0.23) for the distal surfaces of the maxillary molars.