Journal of Dental Research, Dental Clinics, Dental Prospects
Volume:17 Issue: 3, Summer 2023

  Dental erosion is the loss of dental hard tissues through the acid dissolution of tooth minerals. One of the major factors that cause erosion is the consumption of acidic food and drinks. This study investigated and compared the effect of vitamin waters, herbal beverages, carbonated soft drinks, and fruit juices on the loss of human dental hard tissue.

  Human tooth samples were immersed in various drinks: vitamin waters, herbal beverages, carbonated soft drinks, and fruit juices. The pH value of each drink was measured using a pH meter. The weight of each sample was determined before and after six days of immersion in the tested drink, and the weight loss percentage was calculated. The exposed tooth surfaces were also examined under a scanning electron microscope.

Most of the tested drinks were acidic and displayed pH values lower than the critical pH for enamel erosion. Significant weight loss of the tooth samples was found in all tested drink groups. Additionally, the samples immersed in fruit juices and herbal beverages exhibited significantly greater weight loss than those immersed in carbonated soft drinks. Scanning electron micrographs showed samples immersed in the tested drinks to demonstrate structural disintegration with occasional void spaces, except for samples immersed in Doi Kham® Lemongrass drink.

 Most of the tested drinks have the potential to cause dissolution and destruction of dental hard tissues. Consumers should be aware that prolonged exposure to these drinks could lead to permanent loss of tooth mineral and dental erosion.

 This study compared apical extrusion of debris and instrumentation time following root canal instrumentation with Reciproc, Reciproc Blue, and Gentlefile (GF) rotary instruments versus the manual step-back technique.

 This in vitro study was conducted on 80 extracted mandibular premolars with mature apices and a root curvature of<10º. The teeth were randomly assigned to 4 groups (n=20), standardized regarding working length, and placed in pre-weighed vials. The root canals were instrumented with Reciproc, Reciproc Blue, and GF systems and the manual step-back technique in the four groups. The vials containing the collected debris were then dried and weighed. The instrumentation time was also recorded for each group. Data were analyzed with one-way ANOVA and post hoc Games-Howell test (α=0.05).

 Minimum apical debris extrusion was noted in Reciproc, followed by Reciproc Blue, GF, and manual technique (P<0.05). Pairwise comparisons showed significantly lower apical extrusion of debris in the Reciproc compared with GF (P=0.015) and manual instrumentation (P=0.011) groups. The Reciproc system also had the shortest instrumentation time, followed by Reciproc Blue, GF, and manual instrumentation (P<0.05). Pairwise comparisons showed significant differences between all the systems (P<0.05) except between Reciproc and Reciproc Blue (P>0.05) in this respect.

 Although all systems caused apical extrusion of debris, manual instrumentation caused maximum extrusion of debris. In contrast, the Reciproc system was superior to others regarding minimal apical extrusion of debris and the shortest instrumentation time.

This study measured fluoride release from a light-cured orthodontic adhesive resin (Vega type) at three time intervals (one day, one week, and one month), investigated the rechargeability of the resin, and assessed its impact on shear bond strength in demineralized tooth surfaces.

 This study used 30 recently extracted upper premolar teeth to explore the effects of fluoride release over specific time intervals. The teeth underwent demineralization and were categorized into groups based on time intervals: one day, one week, and one month. Subgroups within each interval underwent fluoride recharging through fluoride varnish application. Fluoride release and shear bond strength were assessed after etching with phosphoric acid gel, applying the orthodontic adhesive, and curing. The samples were stored in deionized water. Fluoride quantification used a selective electrode, while shear bond strength assessment employed a universal testing machine. Finally, statistical analysis of the data was performed using SPSS 22.

 The study found that after one month, the adhesive had the highest fluoride release and shear bond strength mean values. There were significant differences in fluoride release and shear bond strength between the various groups studied.

 The application of fluoride varnish around the orthodontic bracket resulted in a positive effect on the shear bond strength of the bracket.

 Cleft lip/palate (CL/P) is a prevalent congenital disorder. Matrix metalloproteinases (MMPs) play a role in palatogenesis and have been proposed to be associated with nonsyndromic CL/P development. This study aimed to examine the association of MMP2 (rs243866) and MMP9 (rs3918242) gene polymorphism with nonsyndromic CL/P in an Iranian population.

 Blood samples were collected from 120 nonsyndromic CL/P patients and 140 healthy newborns in this case-control study. DNA extraction was performed by the salting-out method, and the samples underwent polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP), using Pag and SphI enzymes, for genotyping MMP2 and MMP9 gene polymorphisms. Statistical analysis was performed with SPSS 11.5. Univariate and multivariate logistic regression models were used to calculate the odds ratios and 95% confidence intervals (CIs). The level of statistical significance was set at P<0.05.

No significant association was found between MMP2 gene polymorphism and nonsyndromic CL/P. However, the MMP9 gene polymorphism had a significant association with nonsyndromic CL/P, with a higher prevalence of the T allele and TT genotype in the case group than the control group.

  This study indicated a potential link between MMP9 gene polymorphism and nonsyndromic CL/P in an Iranian population. Future investigations with greater sample diversity and larger sample sizes are required to obtain more comprehensive and robust evidence. In-depth analyses and studies involving different ethnic groups can further enhance our understanding of the genetic underpinnings of CL/P.

 Endodontic infections caused by remaining biofilm following disinfection with chemical fluids encourage secondary bacterial infection; hence, employing laser pulses to activate the fluids is advised to improve microbial biofilm clearance. This study investigated the performance of Er,Cr:YSGG laser in photon-induced photoacoustic streaming (PIPS) agitation of 5.25% sodium hypochlorite (NaOCl) to enhance the removal of mature Enterococcus faecalis (E. faecalis) biofilms in complex root canal systems.

 The mesial roots of the lower first and second molars were separated and inoculated with E. faecalis bacteria for 30 days. The roots were irrigated with 5.25% NaOCl, some of them were agitated with passive ultrasonic irrigation (PUI), and the other roots were agitated by Er,Cr:YSGG laser using PIPS at 60 µs/pulse, 5 Hz, and 0.25, 0.5, 0.75, 1, and 1.25 W. An atomic force microscope (AFM) was used as a new method to obtain the results in the isthmus area; the results that have been obtained from each group were compared with each other. ANOVA was utilized to compare the means of the test groups.

  Based on the AFM and SEM analyses, laser agitation and passive ultrasonic activation groups have shown higher antimicrobial efficacy than the conventional syringe irrigation group (P<0.05).

  Based on the findings of this investigation, the agitation of 5.25% NaOCl solution by Er,Cr:YSGG laser in PIPS at (60 µs/pulse, 5 Hz, 1.25 W) offers better mature bacterial biofilm removal in the mesial root of lower human molars than the same irrigant with syringe irrigation and passive ultrasonic activation technique.

 Dental students learn and practice clinical procedures in clinical skills laboratories. These practices are graded by qualified staff to evaluate the effectiveness of their learning. Valid evaluation requires accuracy and reliability. Although a well-developed checklist for pre-clinical skill evaluation exists in theory, it is challenging to implement in practice. This study was undertaken to develop and evaluate the reliability of an assessment sheet for all-ceramic crown preparations.

 The study consisted of two phases: the development stage and the judgment-quantification stage. Two examiners evaluated all-ceramic crown preparations made by second-year dental students using the developed assessment sheet to test criterion validity. The final grade was determined based on the number of errors identified using the assessment sheet. The relationship between the negative points and the final grades awarded was determined using Spearman’s correlation. The study calculated the intra- and inter-examiner agreement for two rounds of evaluation, conducted one month apart, using Cohen’s unweighted Kappa test. The study employed the Item-Content Validity Index (I-CVI) to evaluate the content validity for each item and the Scale-Content Validity Index (S-CVI) to assess the content validity of the overall scale used in all-ceramic crown preparation procedures.

 The assessment sheet developed for all-ceramic crown preparations was reliable, with strong content validity and a significant negative correlation between grades assigned and the number of errors observed. The assessment sheet defined up to three levels of performance for each item, providing a consistent and objective approach to evaluation. The linear regression graph successfully determined the maximum number of acceptable errors and established the minimum passing grade. The inter- and intra-examiner agreement for the two assessment rounds was found to be fair to moderate.

The study showed that the developed assessment sheet for all-ceramic crown preparations is reliable and can provide a consistent and objective approach to evaluation. It can benefit both students and instructors. Further research is recommended to evaluate the impact of the developed assessment sheet on students’ learning outcomes.

 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.

 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.

 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%).

 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.

One of the methods to control dental caries is to use ozone. Since it is difficult for children to use mouthwashes, the present study aimed to evaluate 20-ppm zone and 1% chlorhexidine (CHX) gels’ effects on the plaque index and Streptococcus mutans counts in 6–12-year-old children.

 In the present double-blind clinical trial, 165 children, 6–12 years of age, referring to the Department of Pediatric Dentistry, Tabriz Faculty of Dentistry, were selected based on inclusion and exclusion criteria and randomly assigned to three groups: ozone gel, CHX gel, and control. The subjects were instructed to place an adequate amount of the gels on all the surfaces of their teeth with one clean finger. The patients and evaluators were blinded to the study groups. The plaque index and S. mutans counts in plaque samples were determined before intervention and three weeks after intervention on the buccal surface of the most posterior maxillary tooth (left or right). S. mutans counts were determined by culture. STATA software version 14 was used for statistical analyses using Wilcoxon, Kruskal-Wallis, and post hoc Dum tests. Statistical significance was defined at P<0.05.

The 20-ppm ozone and 1% CHX gels significantly decreased dental plaque compared to the control group (P<0.05), and their effects were similar (P>0.05). These gels significantly decreased the colonies and bacterial counts of S. mutans (P<0.05).

 The performance of 20-ppm ozone gel in decreasing the dental plaque and S. mutans counts was similar to 1% CHX gel.

 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.

 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.

 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.

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

 Studies have suggested a correlation between periodontitis and reduced male fertility. Inflammation has been described as the link between these ailments. Oral inflammatory load (OIL) can be measured through oral polymorphonuclear neutrophil (oPMN) count, which is associated with periodontal diseases. This cross-sectional study assessed the possible correlation between OIL and the functional parameters of sperm cells.

 In 229 volunteers, oral rinse and semen samples were assessed for oPMN, semen polymorphonuclears (sPMNs), sperm concentration, total sperm count, motility, morphology, and sperm DNA fragmentation index (SDFi). A multiple linear regression model was conducted to evaluate the relationships between oPMN and semen parameters.

 The effect of elevated oPMN counts on total motility rate, progressive rate, and percentage of sperm cells with normal morphology was significant (P<0.001), with an inverse relationship, i.e., with every unit increase in oPMN count, the mentioned parameters would decline by 0.573, 0.367, and 0.407 units, respectively. oPMN counts also correlated positively with sPMN counts and SDFi (P<0.001), i.e., with every unit increase in the oPMN measures, sPMN counts would increase by 0.126 million/mL, with an 0.733% increase in SDFi. However, there was no significant association between oPMN counts and sperm concentration.

 OIL, as represented by oPMN counts, might affect male fertility as there is a positive correlation between the levels of these inflammatory cells and decreased sperm motility, abnormal morphological changes, increased sPMN counts, and increased SDFi.