Journal of Research in Dental and Maxillofacial Sciences
Volume:8 Issue: 4, Autumn 2023

The bite force changes due to alterations in the lever system of the jaw following orthognathic surgery. This study aimed to assess the changes in the maximum bite force of skeletal Class II patients between 18-30 years after orthognathic surgery compared with the preoperative state.

This inception cohort study evaluated 17 patients with skeletal Class II malocclusion (mandibular deficiency) and normal vertical dimension between 18-30 years who underwent mandibular advancement surgery. The maximum bite force on the mandibular first molars was measured preoperatively and at 6 weeks, and 3 and 6 months, postoperatively. The overjet and overbite were also measured on diagnostic casts. Data were analyzed by the Shapiro-Wilk test, Mauchly’s test, the Greenhouse–Geisser correction, and the Spearman and Pearson’s correlation coefficients. 

The mean maximum bite force preoperatively was significantly higher than that at 6 weeks (P<0.001), 3 months (P<0.001), and 6 months (P<0.001), postoperatively. No significant difference was noted in the mean bite force in the right and left sides of the jaw (P=0.589). The overbite and maximum bite force were not significantly correlated in the right (P=0.181) or the left (P=0.134) side, preoperatively. The overjet had no significant correlation with the maximum bite force in the right (P=0.881) or the left (P=0.677) side, preoperatively.

Mandibular advancement surgery in skeletal Class II patients with mandibular deficiency decreases the maximum bite force in the first 6 months, postoperatively.

The most valid method for radiographic estimation of dental age is the Demirjian method. However, the use of Demirjian indices has shown variations among different races worldwide. Therefore, the aim of this study was to investigate the relationship between the chronological age and dental age of 6-15-year-old children in Zanjan, Iran by using the Demirjian method.  

In this descriptive correlational study, 250 panoramic radiographs of children aged 6 to 15 years in Zanjan, Iran were used. The dental age was calculated from the radiographic images based on the calcification stage of all left mandibular teeth according to the Demirjian method. The chronological age and demographic data were collected based on patient records. The relationship between the chronological age and dental age was analyzed by the Spearman correlation coefficient and Wilcoxon test.

There was a strong positive correlation between the chronological age and dental age of all participants (r=0.93).
Comparing the mean chronological age and dental age of the participants showed a significant difference between the two values (P<0.001).

Based on the results of the present study, it may be concluded that despite significant statistical differences, the Demirjian method has sufficient clinical accuracy for dental age estimation in 6–15-year-olds in Zanjan, Iran.

The use of traditional camphorquinone (CQ) photo-initiators in dental composites may cause undesirable yellow discoloration. An alternative photo-initiator called lucirin trimethylbenzoyl-diphenyl-phosphine oxide (TPO) was recently introduced which exhibits minimal color change (ΔE). This study evaluated the color change of TPO-containing composites cured by different types of light-curing units, after accelerated artificial aging (AAA).  

In this in vitro experimental study, specimens were fabricated from Tetric N-Ceram and Vit-l-escence TPO-containing composites with 10 mm diameter and 2 mm thickness (n=10) and light-cured by Bluephase G2 polywave and Bluephase C5 monowave curing units. The samples were polished with Sof-Lex discs and underwent initial colorimetry by a spectrophotometer after 24 hours. Aging was performed for 384 hours in a weathering chamber and final colorimetry was then performed. The results were analyzed by two-way ANOVA.

The interaction effect of light curing unit and composite type on ΔE was not significant (P=0.53). The mean ΔE of Vit-l-escence and Tetric N-Ceram cured with Bluephase G2 and Bluephase C5 light-curing units was 1.67±0.48 and 1.62±0.45, and 2.59±0.29 and 2.69±0.26, respectively. Tetric N-Ceram demonstrated significantly greater ΔE than Vit-l-escence (P=0.001). Light curing units had no significant difference in ΔE (P=0.80).

The ΔE of TPO-containing composites does not depend on the type of light curing unit but depends on the type of composite. Aging caused discoloration of the composites but this discoloration was clinically acceptable (ΔE<3. 3).

Formation of white spot lesions, due to plaque accumulation and bacterial biofilm growth, is a common complication in orthodontic treatment. The present study aimed to compare the antibacterial properties of an orthodontic composite containing silver (Ag) and amorphous tricalcium phosphate (ATCP) nanoparticles against Streptococcus mutans (S. mutans).  

In this in vitro study, 0.3% w/w Ag nanoparticles and 3% w/w ATCP nanoparticles were added to Transbond XT orthodontic composite. Totally, 48 composite discs were fabricated in three groups) n=16). The experimental groups included composite specimens containing nanoparticles and the control group included composite specimens without nanoparticles. The antibacterial effects of composite discs with and without nanoparticles against S. mutans (ATCC 35668) in the three groups were assessed by the direct contact test after 24 hours and 30 days. The number of bacterial colonies was visually counted in the three groups and compared. Data were analyzed by one-way ANOVA and Duncan's multiple comparisons test. P-values under 0.05 were considered significant.

The antibacterial properties of nano-composites significantly increased in both experimental groups of composites containing Ag and ATCP nanoparticles, compared to the control group (P<0.001). The highest antibacterial activity was observed in the orthodontic composite containing ATCP nanoparticles.

Addition of Ag and ATCP nanoparticles to orthodontic light-cure composite increases its antibacterial activity against S. mutans.

A thorough understanding of tooth and root canal morphology is required for successful root canal treatment. The current study aimed to assess the canal and root morphology of maxillary first molars (MFMs) and maxillary second molars (MSMs) using cone-beam computed tomography (CBCT).  

In this cross-sectional study, CBCT scans of 400 patients were used. The number of roots and canals, as well as the morphology of the root canal system of MFMs and MSMs were assessed according to the Vertucci’s classification, separately sorted by gender and by using OnDemand3D dental software. To compare the variables, the Chi-square test was used with a significance level of 0.05.

All the MFMs and MSMs had three roots. The most common morphologies according to the Vertucci’s classification in mesiobuccal (MB) roots of MFMs were type II (43.1%), followed by types I (28.7%), and IV (19.8%); while, types I (63.5%) and II (18.7%) were more commonly found in the MB roots of MSMs. All distobuccal (DB) and palatal roots were type I. The frequency of the second mesiobuccal (MB2) canal in MFMs and MSMs was 71.3% and 36.6%, respectively. Gender had no significant correlation with presence of MB2 canal (P>0.05).

Three roots with four canals were the most common in MFMs while three roots with three canals were the most frequent in MSMs. Variations in MB roots were greater than in other roots. The frequency of MB2 in MFMs was greater than that in MSMs.

Ameloblastoma (AM) and odontogenic keratocyst (OKC) are common lesions with a high recurrence rate. Epidermal growth factor receptor (EGFR) regulates cell proliferation and survival. Considering the controversial results of previous studies regarding the expression of EGFR in odontogenic cysts, this study aimed to compare the expression of EGFR in AM and OKC.  

In this descriptive study, 49 specimens (20 AM and 26 OKC) were evaluated. Five micrometer sections were made for immunohistochemical staining. Immunohistochemical analysis was performed using super-sensitive one-step polymer-HRP. Expression of EGFR was first assessed quantitatively by measuring the count of membrane- and/or cytoplasm-stained epithelial cells in AM  (ameloblastoma-like cells, stellate reticulum, and all epithelial cell layers) and OKC (basal layer, suprabasal and basal layers, and all epithelial cell layers). Next, each specimen's mean percentage of stained cells was scored and classified into four groups (less than 5%, 5-25%, 25-50%, and more than 50% stained cells). Data were analyzed by t-test and Mann-Whitney test to compare the mean EGFR expression and the percentage of stained cells. The Chi-square test was used to compare the location of EGFR expression.

The mean percentage of EGFR expression was 81.39±10.41% in AM and 78.05±19.27% in OKC. The results showed no significant difference between AM and OKC regarding EGFR expression, EGFR score (P=0.141), or EGFR expression in different layers (P=0.303).   

EGFR expression showed no significant difference between AM and OKC.

Dental anxiety and fear are prevalent among adult patients, necessitating behavioral interventions. This study aimed to assess the effectiveness of emotional self-regulation strategies and regular desensitization for alleviation of anxiety and fear of adult dental patients.  

This clinical trial study was conducted on 40 adult dental patients selected by purposeful sampling, who were divided into two groups. Group 1 (n=20) received emotional self-regulation strategies, and group 2 (n=20) underwent regular desensitization. Data were collected using the Dental Fear Survey and Dental Anxiety Inventory (DAI). Group 1 patients participated in 8 sessions of emotional self-regulation, each lasting 1.30 hours, while group 2 were engaged in an 8-session regular desensitization program of the same duration. Data analysis was performed using t-test and paired t-test.

Both emotional self-regulation strategies and regular desensitization significantly decreased the fear and anxiety of adult dental patients (P<0.01). Additionally, there was no statistically significant difference in the impact of emotional self-regulation strategies and regular desensitization on fear and anxiety of dental patients (P>0.05).

Emotional self-regulation strategies and regular desensitization yield comparable effects on the anxiety and fear of adult dental patients.

Pemphigus vulgaris (PV) is a severe life-threatening autoimmune disease that causes intraepithelial blisters. PV has been reported in association with some autoimmune diseases. But only few cases (fewer than 10 reports according to literature search) have been reported regarding the association of PV with multiple sclerosis (MS). MS is a life-threatening, inflammatory demyelinating disease, causing severe disability.  

Our patient was a 40-year-old female complaining of gingival ulcers. She had MS for the past 10 years. Biopsy and immunoassay were done and PV was confirmed. The patient has been followed up for 7 years so far.

It is necessary to pay attention to mild oral ulcers in MS patients because they may be related to severe blistering diseases like PV.

The zygomaticomaxillary complex (ZMC)refers to a main buttress in the skeleton of the midface. When open reduction and rigid fixation is selected as the treatment of choice for a ZMC fracture in pediatric patients, several factors such as immature dentition and growth potential of patient should be taken into account. This case report describes treatment of an old ZMC fracture in a 9-year-old child.   

A 9-year-old child was referred due to left ZMC fracture and orbital floor fracture with severe displacement. Open reduction and internal fixation of the ZMC fracture was performed using titanium plates. The orbital floor was reconstructed with a titanium mesh and the maxillary buttress fracture was reconstructed with an iliac crest bone graft. After surgery, the patient had an appropriate recovery and showed stable results.

In a ZMC fracture with considerable displacement and an orbital floor fracture in children, 3-point fixation with titanium plate and reconstruction of the orbital floor are recommended.

This study reviewed the literature regarding the correlation of periodontal disease and outcome of in vitro fertilization (IVF).

"IVF", "In Vitro Fertilization", and "Periodontitis" were searched in PubMed, Web of Science, and Google Scholar databases to find English articles published up to August 2022. A free online resource developed by the Canadian Agency for Drugs and Technologies in Health was used to search the grey literature. Duplicate screening and extraction of citations were also carried out. No search filter was applied during searching. Two independent reviewers evaluated the title and abstract of the retrieved articles. Next, the articles retrieved in the initial search were reviewed independently for relevant information to the research question.

The relationship between periodontitis and IVF has been studied in a limited number of studies. According to most articles, periodontal disease may affect IVF implantation and vice versa in women who want to conceive through this procedure. Low sperm motility and reduction in sperm count were also seen in males with periodontitis. Only one study found no correlation between the presence of periodontal disease and unwanted IVF results.  

According to the results, periodontitis can impair the reproductive function since it causes systemic bacteremia. Oral health should be addressed by the primary care providers before the onset of any fertility treatment. There is; however, a need for further investigations into the possible implications of periodontal disease in women seeking fertility care.