Journal of Dental Research, Dental Clinics, Dental Prospects最新文献

Background: Considering the limitations of visualization that occur even with the use of radiographs, the cone beam computed tomography (CBCT) becomes more attractive to diagnose and propose an assertive treatment plan. This study aimed to evaluate intra and interobserver reproducibility, and concordance of 31 reference points we described considering visualization tools and the three planes of space in a bimaxillary CBCT.

Methods: Three observers located in triplicate the 31 reference points in the CBCT of six healthy patients. Friedman test was used to compare intraobserver paired samples, and interobserver concordance was determined by the intraclass correlation coefficient (ICC) with ranges>0.75 (excellent), between 0.60 and 0.74 (good), between 0.40 and 0.59 (sufficient) and<0.40 (poor). The P value was set at<0.05.

Results: A high ICC (>0.75%) was obtained by comparing the x, y, and z values at the location of landmark points. Excellent ICC>0.75 was for 81.7% and poor<0.40 was 7.5% in the interobserver evaluation. Data showed that 25 points had excellent concordance on the x-plane, 25 on the y-plane, and 26 on the z-plane (0.75%).

Conclusion: Intraobserver concordance analysis indicated that location of anatomical reference points on bimaxillary CBCT is performed with great reproducibility by interpreting their location with a clear description in the three planes of space. Complexity of achieving a good precision degree in the manual marking of reference points caused by convexities of the anatomical structures involved, might explain the variability found. The systematized location of the reference points would contribute to reduce such variability.

Background: This study evaluated the influence of different tooth preparation techniques and zirconia materials on marginal adaptation.

Methods: Forty-eight healthy human maxillary first premolars were divided into two primary groups based on preparation design: group A (chamfer) and group B (vertical). Within each main group, there were three subgroups, comprising eight teeth each, distinguished by the type of zirconia material employed (Zircad LT, MT, and Prime by Ivoclar Vivadent). All the samples were prepared by the same operator using a dental surveyor. Intraoral scanning was performed on the prepared teeth. SironaInLab CAD 20.0 software was used to design crowns, which were subsequently generated using a 5-axis milling machine. The crowns were cemented to their respective teeth with self-adhesive resin cement. Marginal gap measurements were taken in micrometers (μm) before and after cementation at 16 sites per sample using a digital microscope at×230 magnification. The collected data were evaluated using statistical analysis using the independent t-test, paired t-test, and ANOVA at an 0.05 significance level.

Results: The vertical preparation group exhibited the smallest marginal gap, while the chamfer group displayed the largest. This disparity was statistically significant (P<0.05) for pre- and post-cementation measurements across all materials. There were no significant differences between the different monolithic zirconia crowns.

Conclusion: The vertical preparation design illustrated significantly better marginal adaptation than the chamfer preparation design. Comparisons between materials showed comparable marginal gaps. The mean values of the marginal gaps in all groups increased significantly after cementation.

Background: The role of dairy product consumption on oral cancer risk is not yet fully clarified. Some studies have observed an inverse association between dairy consumption and oral cancer risk. This study aimed to determine the influence of dairy product consumption (milk, cheese, yogurt, butter) on oral cancer risk.

Methods: A search for studies on dairy products and oral cancer was conducted in the following databases: PubMed (MEDLINE, Cochrane Library), Web of Science (WoS), and Scopus. The estimation of the odds ratio (OR) effect was performed with the generic inverse variance method using the logarithm of the effect with the standard error (SE) and 95% confidence intervals.

Results: Twenty-one studies with 59271 participants (8,300 oral cancer patients and 50971 controls) were included in this meta-analysis. All dairy products significantly reduced oral cancer risk except butter (P=0.16). Milk intake reduced oral cancer risk by 27% (OR: 0.73; P<0.001); yogurt consumption by 25% (OR: 0.75; P<0.001), and cheese consumption by 21% (OR:0.79; P<0.01).

Conclusion: Regular consumption of dairy products reduces oral cancer risk between 21% and 27%.

Background: There is no standard protocol for immediate implant placement and subsequent loading in the smile zone. We aimed to evaluate the long-term outcomes of simultaneous implant placement, soft tissue grafting, and immediate prosthetic loading in the esthetic zone.

Methods: Thirty-five implants were placed in the maxillary aesthetic zone. Twenty-two patients were evaluated using the Pink Esthetic Score (PES) and White Esthetic Score (WES). Also, the degree of peri-implant bone resorption and patient survey were applied for the esthetic and functional outcomes.

Results: The esthetic and harmonizing outcomes were achieved according to the mean total PES/WES value (17.9±2.0). The mean overall PES was 8.5±1.66. The papilla level had the highest mean score (1.8±0.36). Furthermore, the combination of root convexity/color and soft tissue color and texture was one of the key values in evaluating the effectiveness of this method (the mean value was 1.5±0.5). The mesial and distal papillae were 1.6±0.5 and 1.8±0.4, respectively. None of the 35 implants reached below 6 points (which is considered an esthetically unsatisfactory result). The mean WES score was 9.5±0.57. The average degree of total peri-implant bone resorption was 1.05±0.3 mm after 12 months. According to the questionnaire, all the patients smiled without hesitation and were satisfied with the treatment (100%).

Conclusion: This study showed that restoring one or more teeth in the smile zone using the concept of one-stage implant placement, soft tissue flap augmentation, and loading with provisional crowns was an esthetically successful and predictable method.

Background: The temporomandibular joint (TMJ) is the most commonly used joint in the human body. Recent studies have shown pathologic relationships between inflammation, diabetes, and musculoskeletal disorders (MSDs). Chewing disorder is a significant sign of dysfunction in the masticatory system. This study investigated dietary pattern changes in response to TMJ inflammation in diabetic rats.

Methods: This experimental study was carried out on 30 male rats. The rats were fed concentrated 20-mg dietary tablets. Complete Freund's adjuvant (CFA) was used to induce TMJ inflammation and streptozotocin (STZ) was used to induce diabetes. The animals were randomly divided into three groups (n=10), including group I (CFA+STZ), group II (healthy rats+CFA), and group III (healthy rats, no injection). Parameters such as overall food intake, food intake duration, food intake frequency, and the interval between meals were recorded in a checklist and analyzed by Mann-Whitney and Kruskal-Wallis tests (P<0.05).

Results: The results showed no significant difference between groups in overall food intake and food intake frequency on days 0 and 1, but this difference was significant from day 2 to day 7. Regarding the time and end of food intake, there was a significant difference between the three groups from day 1 to day 7, but this difference was not significant on day zero.

Conclusion: Dietary pattern changes were similar in the diabetic TMJ inflammation and TMJ inflammation groups. These changes can be used as a behavioral marker for TMJ inflammation in rats.

Background: This study aimed to measure the shear bond strength and compressive strength of orthodontic adhesives at different curing times and intensities.

Methods: Ninety extracted human premolars were used. Orthodontic brackets were bonded on the buccal surface of the teeth with orthodontic adhesive light-cured using VRN-VAFU LED curing light at different curing times (1, 3 and 5 seconds) and intensities (1000, 1600 and 2300 mW/cm² ). A universal testing machine was used to measure the shear bond strength. The ratio of the adhesive remnant and compressive strength of the orthodontic adhesive, at each curing time at the different intensities, were also evaluated. The results were statistically analyzed using one-way analysis of variance followed by Tukey's test.

Results: The lowest bond strength values (6.4, 9.9 and 12.6 MPa) were recorded with 1000 mW/ cm² intensity (at all curing times) in comparison with the other intensities (P<0.05). Increasing the curing time significantly increased the bond strength of the orthodontic brackets (P<0.05), except when the curing time was increased from 3 sec to 5 sec at 1600 mW/cm² intensity. The highest compressive strength values (130.3, 147.1 and 174 MPa) were recorded at 2300 mW/ cm² intensity (at all curing times) compared to the other intensities (P<0.05). The highest values of the ratio of the adhesive remnants were recorded at 1000 mW/cm² intensity (at all curing times) compared to the other intensities (P<0.05).

Conclusion: Although, increasing the curing time andor the curing intensity has a positive effect on the bond strength and compressive strength of the orthodontic adhesive, it might be possible to suggest reducing the curing time of orthodontic adhesive to 1 sec at curing intensity of 2300 mW/cm².

Background: Bonding is an important step in fixed orthodontic therapy and evaluation of bracket bond failures while using different bonding systems is required. The aim of the present study was to evaluate and compare bracket failure rates of a novel no primer adhesive with conventional primer-based orthodontic adhesives.

Methods: This split mouth study was conducted among fifteen patients who underwent therapy with fixed orthodontic appliances using metal brackets. Total of 300 brackets were bonded and the bracket bond failure rates were assessed at the end of 3 months. The difference in bond failure rates between the two groups were assessed in different teeth. Descriptive statistics and chi-square test was performed.

Results: Evaluation of bracket bond failure rates showed a higher incidence of bond failures in the group bonded with the primerless adhesive (6.3%) compared to conventional adhesive (2.3%) but there was no statistically significant difference (P>0.05). No intergroup difference was found in the bracket failure rates of individual teeth (P>0.05).

Conclusion: Higher incidence of bond failures were noted with brackets bonded with primerless adhesive when compared to primer-based adhesive but no significant difference was noted over a period of 3 months. Mandibular canine and premolars had a higher bracket failure rate with no significant difference between the adhesives.

Background: Numbing the area of oral mucosa with cold application prior to administration of regional anesthesia has been widely used by various dentists in alleviating pain caused by needle prick. Cryoanesthesia using Endo-ice as topical anesthesia has been studied as a replacement to prevail the fallibility of topical anaesthetics. This study aimed to evaluate and compare effectiveness of ethyl chloride spray with 5% lidocaine gel in alleviating buccal anesthesia injection pain.

Methods: Total of 90 outpatients were randomly divided into 3 groups as follows: Group 1 - cryotherapy with ethyl chloride at the anesthetic site preceding before administration of local anesthesia; Group 2 - topical application of 5% LIDOCAINE GEL preceding before administration of local anesthesia; and group 3 - control that did not receive any topical agent preceding before administration of local anesthesia. Visual analogue scale (VAS) was used to document pain immediately after injection prick.

Results: About comparison of pain scores, significant difference was found between group 1 (ethyl chloride) and group 2 (topical lidocaine) patients (P=0.001). For group 1, about 15 (50%) patients suffered from mild pain, followed by 14 (46.67%) patients suffering from moderate pain. However, majority of the 21 (70%) patients in group 2 suffered from moderate pain. All the patients in group 3 suffered from severe pain.

Conclusion: Importance of alleviating fear of needle injection phobia amongst patients is of paramount importance. Ethyl chloride was found to be more effective than topical lidocaine in alleviating needle injection pain before administration of local anesthetic injection.

Background: Pulpotomy is a vital pulp treatment procedure frequently used in primary molars to preserve pulp vitality and function until tooth exfoliation. There is currently no pulp medicament with all the features of the ideal pulpotomy material. The present study compared the radiographic success of sodium hypochlorite with ferric sulfate (FS) when used for pulpotomy in primary molars.

Methods: A retrospective analysis was performed to evaluate the success rates of primary molars pulpotomized using sodium hypochlorite or FS according to radiographic findings. Healthy 4‒10-year-old children who had pulpotomy procedures on primary molars between 2018 and 2021 at the pediatric dental clinic and had a control radiograph at least 12 months later were enrolled in the study. The chi-squared test was used to determine the differences in success between these two materials.

Results: A total of 142 teeth, including 85 (59.9%) first primary molars and 57 (40.1%) second primary molars, in 98 healthy children were evaluated. The mean follow-up period of the teeth included in the study was 585.1±249.4 days. Radiographic success rates for NaOCl and FS groups were 73.8% and 71.0%, respectively, with no statistically significant difference (P>0.05). Internal root resorption (IRR) was the most common cause of radiographic failure in both groups.

Conclusion: Radiographic success rates of both materials were similar, and using these materials in primary molar pulpotomy procedures can be recommended in clinical practice.

Background: To compare and assess the enamel surface roughness by Atomic Force Microscopy between ceramic and metal brackets after adhesive removal with 3 different methods.

Methods: 90 extracted premolars were collected and divided equally into 3 groups G, Y, and R. With group G bonded with metallic brackets (using primer and Transbond XT), group Y with ceramic brackets (primer and Transbond XT), and group R with ceramic brackets (silane and Transbond XT). Each group was subdivided into 3 sub-groups (10 premolars each) based on the resin removal method as A: 12- flute tungsten carbide (TC) bur (high speed), B: 12- flute TC bur (low speed), and C: 30 flute TC bur (low speed). Surface roughness values were calculated and compared before bonding and also after adhesive removal by atomic force microscope (AFM). Measured data were analyzed using paired student t-test, ANOVA, and Tukey's tests.

Results: Among the groups, group G showed increased surface roughness after debonding compared to group Y and group R, with Rq value showing a statistically significant difference (P<0.047). Whereas, within the subgroups, subgroup A (12-flute TC, high speed) with Rq showed increased surface roughness which was found to be statistically significant (P<0.042).

Conclusion: None of the adhesive removal methods was capable to restore the enamel to its earlier morphology; a statistically significant increase in surface roughness parameters was reported with a high-speed 12 flute TC bur for Rq and Rt.