Comparison of implant stability measurements between a resonance frequency analysis device and a modified damping capacity analysis device: an in vitro study

PURPOSE: A stability-measuring device that utilizes damping capacity analysis (DCA) has recently been introduced in the field of dental implantology. This study aimed to evaluate the sensitivity and reliability of this device by measuring the implant stability of ex vivo samples in comparison with a resonance frequency analysis (RFA) device.METHODS: Six implant beds were prepared in porcine ribs using 3 different drilling protocols to simulate various implant stability conditions. Thirty-six pork ribs and 216 bone-level implants measuring 10 mm in height were used. The implant beds were prepared using 1 of the following 3 drilling protocols: 10-mm drilling depth with a 3.5-mm-diameter twist drill, 5-mm drilling depth with a 4.0-mm-diameter twist drill, and 10-mm drilling depth with a 4.0-mm-diameter twist drill. The first 108 implants were external-connection implants 4.0 mm in diameter, while the other 108 implants were internal-connection implants 4.3 mm in diameter. The peak insertion torque (PIT) during implant placement, the stability values obtained with DCA and RFA devices after implant placement, and the peak removal torque (PRT) during implant removal were measured.RESULTS: The intraclass correlation coefficients (ICCs) of the implant stability quotient (ISQ) results obtained using the RFA device at the medial, distal, ventral, and dorsal points were 0.997, 0.994, 0.994, and 0.998, respectively. The ICCs of the implant stability test (IST) results obtained using the DCA device at the corresponding locations were 0.972, 0.975, 0.974, and 0.976, respectively. Logarithmic relationships between PIT and IST, PIT and ISQ, PRT and IST, and PRT and ISQ were observed. The mean absolute difference between the ISQ and IST values on a Bland-Altman plot was −6.76 (−25.05 to 11.53, P<0.05).CONCLUSIONS: Within the limits of ex vivo studies, measurements made using the RFA and DCA devices were found to be correlated under a variety of stability conditions.

Efficacy of different tooth-brushing methods for removing dental plaque / 대한구강보건학회지

OBJECTIVES: This study aimed to measure the efficacy of different tooth-brushing methods for removing plaque in Korea. METHODS: This study was conducted with the approval of the Institutional Review Board (IRB) of the Seoul National University School of Dentistry (S-D20180021). Thirty participants aged between 19 and 30 years, who did not have periodontal disease, were enrolled in this observational study. Participants were given the same type of toothbrush and toothpaste and asked to brush their teeth as they usually would. During brushing, participants were recorded with a camcorder that was attached to a mirror. Participants were aware they were being recorded. After they had finished brushing their teeth, a dental plaque staining and oral plaque index (PI) examination was performed. The PI score was measured using the Turesky modified Quigley Hein Index. Brushing methods were classified as rolling, horizontal, vertical, circling, and oblique. Skipped surfaces were recorded separately. Following this, statistical analysis was performed using SPSS software. RESULTS: Most surfaces of the mouth were skipped. The most commonly used brushing method was the circling method, followed by the vertical, horizontal, rolling, and oblique methods. The most frequently used method on the vestibular surface was circling, with 52.92% of the oral surface skipped. The oblique brushing method had the lowest mean PI score with a mean±SD of 1.73±0.82. The mean PI score of the skipped surfaces was the highest with a mean±SD of 2.52±0.81. We also analyzed the linear mixed model considering the different lengths of time spent brushing. Both the brushing method used and the time spent brushing had a significant effect on the PI score, but no interactions between these were observed. In areas where a horizontal brushing method had been used, the PI score was significantly decreased. CONCLUSIONS: This study suggests that the horizontal brushing method is an efficient tooth-brushing method compared to the other methods. Additionally, tooth-brushing for more than 10 seconds on 3 to 4 teeth area was effective in removing dental biofilm.

Association between semi-solid yogurt intake and periodontitis in Korean adults

PURPOSE: The purpose of this study was to examine the association between the intake of semi-solid yogurt and periodontitis in Korean adults using a national database. METHODS: The data analyzed in this study are a subset of the sixth Korean National Health and Nutrition Examination Survey conducted in 2015 by the Korea Centers for Disease Control and Prevention. The sample size for this study was 4,727. We collected data on sociodemographic characteristics, oral health-related variables, oral and general health status, and intake of semi-solid yogurt. Semi-solid yogurt intake (YI) was calculated by multiplying the frequency of YI over the previous week by the average intake per serving. We assessed periodontal conditions using the Community Periodontal Index (CPI) and defined periodontitis as a CPI score ≥3. Multivariate logistic regression analyses were performed after adjusting for sociodemographic variables, and oral and general health behaviors and status. RESULTS: The mean weekly YI among those without periodontitis (1.03±0.06 cups) was significantly higher than among those with periodontitis (0.77±0.08 cups) (P<0.001). Individuals who consumed more than 2 cups of yogurt per day were 76% less likely to have periodontitis than those who consumed less than 1 cup of yogurt per week after adjusting for all covariates (odds ratio, 0.24; 95% confidence interval, 0.10–0.60). CONCLUSIONS: We found a significant association between increased intake of semi-solid yogurt and periodontal health. We therefore recommend daily consumption of semi-solid yogurt as a probiotic to improve periodontal health. Further longitudinal studies are required to elucidate plausible mechanisms through which probiotics impact periodontal disease, considering both periodontal pathogens and clinical periodontal parameters.

Possibility of predicting missing teeth using deep learning: a pilot study / 대한구강보건학회지

OBJECTIVES: The primary objective of this study was to determine if the number of missing teeth could be predicted by oral disease pathogens, and the secondary objective was to assess whether deep learning is a better way of predicting the number of missing teeth than multivariable linear regression (MLR).METHODS: Data were collected through review of patient’s initial medical records. A total of 960 participants were cross-sectionally surveyed. MLR analysis was performed to assess the relationship between the number of missing teeth and the results of real-time PCR assay (done for quantification of 11 oral disease pathogens). A convolutional neural network (CNN) was used as the deep learning model and compared with MLR models. Each model was performed five times to generate an average accuracy rate and mean square error (MSE). The accuracy of predicting the number of missing teeth was evaluated and compared between the CNN and MLR methods.RESULTS: Model 1 had the demographic information necessary for the prediction of periodontal diseases in addition to the red and the orange complex bacteria that are highly predominant in oral diseases. The accuracy of the convolutional neural network in this model was 65.0%. However, applying Model 4, which added yellow complex bacteria to the total bacterial load, increased the expected extractions of dental caries to 70.2%.On the other hand, the accuracy of the MLR was about 50.0% in all models. The mean square error of the CNN was considerably smaller than that of the MLR, resulting in better predictability.CONCLUSIONS: Oral disease pathogens can be used as a predictor of missing teeth and deep learning can be a more accurate analysis method to predict the number of missing teeth as compared to MLR.

The preliminary study for three-dimensional alveolar bone morphologic characteristics for alveolar bone restoration / 대한악안면성형재건외과학회지

BACKGROUND@#The concept of the ideal morphology for the alveolar bone form is an important element to reconstruct or restore the in maximizing esthetic profile and functional alveolar bone restoration. The purpose of this preliminary study is to evaluate the normal alveolar bone structure to provide the standard reference and guide template for use in diagnosing for implant placement, determining the correct amount of bone augmentation in actual clinical practice and producing prostheses based on three-dimensional imaging assessment of alveolar bone.@*METHODS@#This study was included 11 men and 11 women (average age, 22.6 and 24.5 years, respectively) selected from among 127 patients. The horizontal widths of alveolar bone of maxilla and mandible were measured at the crestal, mid-root, and root apex level on MDCT (multi-detector computed tomography) images reconstructed by medical imaging software. In addition, tooth dimensions of the central incisors, canines, second premolars, and first molars of maxilla and mandible, including the horizontal width of the interdental alveolar bone crest, were also measured and statistically analyzed.@*RESULTS@#The horizontal alveolar bone width of the palatal side of maxilla showed a distinct increment from the alveolar bone crest to the apical region in both anterior and posterior areas. The average widths of the maxillary alveolar ridge were as follows: central incisor, 7.43 mm; canine, 8.91 mm; second premolar, 9.57 mm; and first molar, 12.38 mm. The average widths of the mandibular alveolar ridge were as follows: central incisor, 6.21 mm; canine, 8.55 mm; second premolar, 8.45 mm; and first molar, 10.02 mm. In the buccal side, the alveolar bone width was not increased from the crest to the apical region. The horizontal alveolar bone width of an apical and mandibular border region was thinner than at the mid-root level.@*CONCLUSIONS@#The results of the preliminary study are useful as a clinical guideline when determining dental implant diameter and position. And also, these measurements can also be useful during the production of prefabricated membranes and customized alveolar bone scaffolds.

Remineralization ability of fluoride varnish containing tricalcium phosphate by time / 대한구강보건학회지

OBJECTIVES: The aim of this study was to evaluate the degree of remineralization over time after application of fluoride varnish with and without tricalcium phosphate (TCP). METHODS: This in vitro study used extracted bovine lateral incisors without dental caries. Artificial lesions were created in the enamel specimens. The amount of mineral loss (ΔF(before)) was measured using quantitative light-induced fluorescence (QLF). Test fluoride varnishes (10 mg) were applied to the enamel surface of the specimen and dried for 4 min. No fluoride varnish was applied to the specimens in the control group. Each group was randomly assigned 12 specimens, and remineralization was allowed to occur to different time points (0.5, 1, 3, 6, 12, and 24 h) in each group. Specimens were washed with distilled water and dried with compressed air for 3 s. ΔF(after) was determined using QLF. RESULTS: When fluoride varnish containing TCP was applied for up to 6 h, the amount of mineral loss significantly increased, and when non-TCP fluoride varnish was applied for up to 12 hours, the amount of mineral loss significantly increased (P<0.05). However, the amount of mineral loss was higher in the control group. The difference between ΔF(before) and ΔF(after) (ΔΔF) increased over time. There was a significant difference between the TCP group and the control group after 6 h. The non-TCP group showed a significant difference after 24 h compared to the control group. After 12 h, significant differences were observed in the TCP group compared to both the non-TCP and control groups. CONCLUSIONS: This study showed that the degree of remineralization increased gradually over time after fluoride varnish application compared to the control group. In particular, fluoride varnish containing TCP showed better remineralization capability than varnish without TCP.

Effectiveness of a baking soda dentifrice on gingivitis and tooth surface / 대한구강보건학회지

OBJECTIVES: To evaluate the effectiveness of sodium bicarbonate dentifrices in reducing gingivitis and tooth abrasiveness and improving tooth gloss, as compared to a conventional fluoride/silica-containing dentifrice. METHODS: In this double-blinded, randomized clinical study with a paralleled design, 73 healthy adult volunteers (age, 18-39 years), with more than 20 teeth were selected and randomly allocated to the following groups: a control group, a 35% baking soda group, and a 65% baking soda group. Professional plaque controls were provided to all subjects and the same control dentifrice was used for 14 days. At baseline, all subjects received an assigned dentifrice and were instructed to brush three times daily. The tooth gloss and gingival bleeding index were measured at baseline, 45, and 90 days. For measuring surface roughness, toothbrushes were replaced with electronic tooth-brushing machines, and the bovine specimen was brushed via 10,000 horizontal shuttle movements. The surface roughness was measured by a confocal laser scanning microscope (CLSM; Carl Zeiss, LSM-5 Pascal, Germany) Each variable was analyzed by the paired t-test, and change in each variable among groups was analyzed by analysis of variance (ANOVA). Reliability of the gloss was analyzed by an intra-class correlation coefficient. RESULTS: Compared to the controls, the 65% sodium bicarbonate dentifrice group showed significant improvement with regard to the tooth gloss for 90 days as well as a significant inhibitory effect on gingivitis; the 35% sodium bicarbonate dentifrice group, however, showed no inhibitory effect on gingivitis. The relative roughness of the tooth surface in the dentifrices of both the sodium bicarbonate dentifrice groups was significantly low. Further, there was no significant difference with the distilled water group. CONCLUSIONS: The sodium bicarbonate dentifrice has an inhibitory effect on gingivitis. Further, this dentifrice showed low abrasiveness and a glossing effect on teeth.

Expert's opinions on the National Oral Health Examination evaluation system / 대한구강보건학회지

OBJECTIVES: The Delphi study was performed in Korea to develop a consensus opinion for the quality improvement in National oral health examination, and to obtain a basic data on how to improve the evaluation system of the National health examination. METHODS: Consensus was developed through two rounds of assessment in September and October, 2011. Seven professors and six dentists, recommended by Korean Dental Associations, were chosen as the Delphi experts. The Delphi questionnaire collected data in the following categories; management of facilities, preparation before oral screening, notice, certification of human resource, preservation of oral screening sheets, charge for oral screening, notification of agreement with using oral screening data, and the notification of oral screening results. To develop new criteria, the additional delphi questionnaire collected data in the following categories; human resource for dental screening, relevancy of instruments and facilities, a dental screening process. Respondents were asked to indicate their level of agreement with the questionnaire statements on a scale from 0 to 9 (0 indicating total disagreement and 9 indicating total agreement). The mean, coefficient of variation, median and agreement level were calculated. Agreement level was calculated by the proportion of respondents who chose more than 7. Consensus was considered to be defined when the agreement level was more than 45% in each section. RESULTS: Consensus was achieved in every criterion except for management of facilities, charge for oral screening and notification of agreement with using oral screening data. In new criteria, consensus was achieved in every criterion except for human resource for dental screening. CONCLUSIONS: Experts for the National Oral Health Examination in Korea achieved a consensus on certain aspects of the evaluation system of the National Oral Health Examination. It is needed to consider an improvement of the evaluation criteria on the National Oral Health Examination program.