Clinical and histological evaluations of alveolar ridge augmentation using a novel bi-layered porous polyethylene barrier membrane.

Guided bone regeneration (GBR) is an effective alveolar ridge reconstruction technique used before or at implant placement. The combination of various barrier membranes and bone substitutes has been employed. This study aimed to perform a preliminarily evaluation of the safety and performance of a new nonabsorbable bi-layered porous polyethylene (PPE) membrane, in combination with a freeze-dried cortical bone allograft in posterior mandibular ridge augmentation. Fifteen adults who had combined posterior mandibular defects were included for ridge augmentation via GBR using PPE membrane and allograft before implant placement. The keratinized mucosa width (KW), ridge width (RW), ridge height (RH), distance from measurement matrix to bone (DMB), and horizontal alveolar width at 14.0 mm apical to the occlusal plane (HAW) were clinically measured at 15 intended implant sites before and after the augmentation. Fifteen biopsy specimens were harvested at the implant sites for histological analysis. All the subjects completed the whole study. The KW and RH showed minor gains by 0.2 ± 1.4 mm and 0.9 ± 2.3 mm respectively; however, no statistically significant differences were found between, before, and after the augmentation (P > 0.05). In contrast, the RW and HAW significantly increased by 4.8 ± 1.6 mm and 2.3 ± 1.7 mm, respectively, (P ≤ 0.001), while DMB significantly decreased by 1.0 ± 0.8 mm after treatment (P < 0.001). Histological analysis revealed that allograft underwent active bone remodeling. The PPE membrane was adequately safe and efficient to use with allograft in GBR for the reconstruction of combined ridge defects. Although some complications were observed, these were manageable and subsequently lead to successful implant placement for all the subjects. However, further randomized controlled trials are still needed to confirm these findings.

Caries detection under composite restorations by laser fluorescence and digital radiography.

OBJECTIVES: The objective of this study is to assess the potential of DIAGNOdent readings in detecting carious lesions under composite resin restorations in comparison with digital radiography. MATERIALS AND METHODS: One hundred extracted third molars were visually selected: 50 with and 50 without carious lesions. Class I occlusal cavities were prepared. In the carious group, caries were left on the floor of cavities before composite resin restoration. The occlusal surface relevant to the caries position in the carious group and a counterfeit point in the non-carious group were marked for DIAGNOdent reading. Teeth were fixed in a plaster box. Digital radiographs were taken and examined by four observers. Definitive diagnosis of caries was based on a histological assessment. Diagnostic accuracy for each method was expressed by the area under the receiver operating characteristic (ROC) curve. Differences between the areas under the ROC curves were assessed using the McNemar test. RESULTS: The respective sensitivity (95 % confidence interval (%CI)) and specificity (95 %CI) of DIAGNOdent were 0.74 (0.66-0.83) and 0.84 (0.76-0.92). The respective average diagnostic performance values for digital radiographs assessed by four observers were 0.54 (0.36-0.72) and 0.77 (0.65-0.86). The respective ROC values for DIAGNOdent and digital radiographs based on four observers were 0.79 and 0.65. Cohen's kappa statistic revealed a moderate to substantial agreement among interobserver reliabilities (k = 0.60-0.77). CONCLUSIONS: There were no statistically significant differences between DIAGNOdent and digital radiographs for the detection of dental caries under composite restoration (p value > 0.05). CLINICAL RELEVANCE: DIAGNOdent was developed to detect caries on occlusal surfaces and was tested for caries adjacent to filling materials. This study demonstrated the use of DIAGNOdent in detecting caries under old composite restorations.

Performance of an artificial neural network for vertical root fracture detection: an ex vivo study.

AIM: To develop an artificial neural network for vertical root fracture detection. MATERIALS AND METHODS: A probabilistic neural network design was used to clarify whether a tooth root was sound or had a vertical root fracture. Two hundred images (50 sound and 150 vertical root fractures) derived from digital radiography--used to train and test the artificial neural network--were divided into three groups according to the number of training and test data sets: 80/120,105/95 and 130/70, respectively. Either training or tested data were evaluated using grey-scale data per line passing through the root. These data were normalized to reduce the grey-scale variance and fed as input data of the neural network. The variance of function in recognition data was calculated between 0 and 1 to select the best performance of neural network. The performance of the neural network was evaluated using a diagnostic test. RESULTS: After testing data under several variances of function, we found the highest sensitivity (98%), specificity (90.5%) and accuracy (95.7%) occurred in Group three, for which the variance of function in recognition data was between 0.025 and 0.005. CONCLUSIONS: The neural network designed in this study has sufficient sensitivity, specificity and accuracy to be a model for vertical root fracture detection.

Shape of the lingula and its localization by panoramic radiograph versus dry mandibular measurement.

BACKGROUND: To evaluate the incidence of lingula shapes in Thai adult mandibles and to compare the accuracy of panoramic radiograph measurement with the dry mandible measurements for localizing the position of the lingula. METHODS: Seventy-two dry adult mandibles (144 sides) from 52 males and 20 females of Thai origin were classified as triangular, truncated, nodular or assimilated. Twenty-three mandibles, composed of both first molar and canine on the same side (33 sides), were selected for distance measurement. The ten distances from the lingula to the anterior, posterior ramus, to the coronoid notch and lower border of the mandible were measured on the dry mandibles and compared with the same distances on panoramic radiographs. The distribution of the lingula shape is described. Paired t test and correlation were used to evaluate the accuracy of panoramic radiographs in localizing the position of the lingula. RESULTS: Truncated lingula were most commonly found (68 sides or 47%). Nodular, triangular and assimilated shapes were found in 33 (23%), 24 (17%) and 19 subjects (13%), respectively. The distance differences between the panoramic radiograph measurement and the dry mandible measurement were statistically significant (P < 0.01). The positive correlations between the panoramic and dry skull measurements were high (0.59-0.91). CONCLUSIONS: The lingula has different shapes in different populations. In adult Thai mandibles, the truncated lingula shape is most common. Panoramic radiographs present not only the position but also the shape and number of lingula and mandibular foramen. There is a high concordance between the measured distances in panoramic radiography and dry mandibles.

Bitewing film quality: a clinical comparison of the loop vs. holder techniques.

OBJECTIVE: To compare in vivo bitewing film quality using the holder versus the paper loop technique. METHOD AND MATERIALS: Four bitewing films were taken from the right and left premolar and molar regions of 45 dental students using both the bitewing holder and paper loop techniques. A total of 360 films were taken and assessed by an experienced practitioner not apprised of the bitewing technique used. Of interest were: (1) the number of overlaps and the percentage of teeth showing the alveolar crest; (2) proper film positioning; and (3) the percentage of cone cutting. A Poisson regression using generalized estimating equations (GEEs) was used to estimate the difference in overlap between the two techniques. For proper positioning and cone cutting, logistic regressions using GEEs were used. RESULTS: The average number of horizontal overlaps for the loop and holder techniques at the right premolar, right molar, left premolar, and left molar were 1.64, 2.11, 2.16, 2.78, and 1.64, 2.00, 2.00, 2.18, respectively. The loop technique was 1.11 times more likely to cause overlapping than the holder technique. The highest percentage of teeth showing the alveolar crest by the loop technique was 97.8% in the mandibular second premolar and first molar. With respect to film positioning, the loop technique was 1.12 times more likely to cause improper positioning than the holder technique. Both techniques demonstrated minimal cone cutting (1 in the loop versus 0 in the holder). CONCLUSION: The quality of bitewing films taken by the loop and holder techniques was not significantly different.

Root fracture detection on digital images: effect of the zoom function.

UNLABELLED: To assess the accuracy of root fracture detection at various levels of image magnification. METHODS: Extracted single-rooted human teeth (100 non-fractured and 101 fractured) were mounted singly in wax blocks and a charge-coupled device (CCD)-based digital Sidexis imaging system was used to take images using the paralleling technique. Image sizes 1 : 1, 2 : 1, and 1 : 2 were prepared for each tooth. All 603 images were examined randomly and interpreted by an experienced radiologist unaware of which images were of fractured roots. The degree of agreement between image interpretation and the actual condition was estimated using a kappa statistic. A modified goodness-of-fit chi2-test was used to assess the significance of the difference between the three image sizes. The sensitivity, specificity, predictive value, and likelihood ratio were used to evaluate the accuracy of root fracture detection at each level of magnification. The degree of agreement between pairs of viewing conditions was also calculated using a kappa statistic. RESULTS: There was substantial agreement between image interpretation and the actual condition for both the 1 : 1 and 1 : 2 image sizes but only moderate agreement for the 2 : 1 size. The kappa values (and 95% CIs) were 0.65 (0.51-0.79), 0.63 (0.49-0.77), and 0.58 (0.44-0.72), respectively. The differences were not statistically significant (P-value = 0.79). The sensitivity (95% CI) of the image magnification ranged between 79.0% (70.0-87.5%) and 81.0% (72.2-87.5%). The 1 : 1 image size gave the highest specificity of 86.1% (95% CI: 78.1-91.6%). The positive predictive values (95% CI) of the 1 : 1, 1 : 2, and 2 : 1 images sizes were 84.9% (76.3-90.8%), 81.8% (73.1-88.2%), and 77.9% (69.0-84.8%), respectively. The negative predictive values (95% CI) were 80.6% (72.1-86.9%), 81.4% (73.8-88.9%), and 80.4% (71.4-87.1%) for the 1 : 1, 1 : 2, and 2 : 1 image sizes, respectively. The likelihood ratios of the positive test (95% CI) were 5.70 (3.47-9.36), 4.55 (3.00-6.98), and 3.56 (2.45-5,16) for the 1 : 1, 1 : 2, and 2 : 1 image sizes, respectively. The likelihood ratios of the negative test (95% CI) were 0.24 (0.17-0.36), 0.23 (0.15-0.35), and 0.25 (0.16-0.37) for the 1 : 1, 1 : 2, and 2 : 1 image sizes, respectively. The reliability between pairs of viewing conditions was substantial. The kappa statistics (95% CI) was 0.80 (0.72-0.88), 0.73 (0.64-0.83), and 0.77 (0.68-0.86), respectively. CONCLUSION: In this in vitro study, the three digital magnifications used did not affect the detection of root fractures.