Association of Tumor Necrosis Factor-Alpha, Interleukin-1ß, Interleukin-8, and Interferon-γ with Obstructive Sleep Apnea in Both Children and Adults: A Meta-Analysis of 102 Articles.

Background: Cytokines may have a significant impact on sleep regulation. In this meta-analysis, we present the serum/plasma levels of tumor necrosis factor-alpha (TNF-α), interleukin (IL)-8, IL-1ß, and interferon-gamma (IFN-γ) in both children and adults with obstructive sleep apnea (OSA) in comparison to controls. Methods: Four electronic databases were systematically searched (PubMed, Web of Science, Scopus, and Cochrane Library) through 19 October 2023, without any restrictions on language, date, age, and sex. We used Review Manager version 5.3 to perform meta-analysis and presented the data as standardized mean difference (SMD) and 95% confidence interval (CI) values to evaluate the relationships between the levels of cytokines and OSA. Results: A total of 102 articles (150 independent studies) were included in the meta-analysis. The pooled SMDs in adults were 1.42 (95%CI: 1.11, 1.73; p < 0.00001), 0.85 (95%CI: 0.40, 1.31; p = 0.0002), 0.69 (95%CI: 0.22, 1.16; p = 0.004), and 0.39 (95%CI: -0.37, 1.16; p = 0.31) for TNF-α, IL-8, IL-1ß, and IFN-γ, respectively. The pooled SMDs in children were 0.84 (95%CI: 0.35, 1.33; p = 0.0008), 0.60 (95%CI: 0.46, 0.74; p < 0.00001), 0.25 (95%CI: -0.44, 0.93; p = 0.49), and 3.70 (95%CI: 0.75, 6.65; p = 0.01) for TNF-α, IL-8, IL-1ß, and IFN-γ, respectively. Conclusions: The levels of proinflammatory cytokines of TNF-α, IL-8, and IL-1ß in adults, and TNF-α, IL-8, and IFN-γ in children with OSA, are significantly higher than those in controls.

Correlation of social smile symmetry with facial symmetry.

BACKGROUND: This study aimed to assess the correlation of social smile symmetry with facial symmetry. METHODS: In this cross-sectional study, frontal view photographs were obtained from 169 eligible patients at rest and smiling with a camera at the level of their nose tip. Several landmarks were selected for facial symmetry and measured at rest and social smiling at the two sides of the face. The respective formula was used to calculate the asymmetry index (AI). The mean values for each AI were calculated, and the correlation between the criteria for a symmetric smile in a social smile with the criteria for facial symmetry, and the correlation between the difference in symmetry criteria at rest and social smiling with facial symmetry criteria were analyzed. RESULTS: Significant correlations were noted between Oc-b AI (smile) and Sn-B (rest) facial AI (P = 0.046), An-a (smile) AI and Gn-a (rest) facial AI (P = 0.002), An-b (smile) AI and Sn-b (rest) facial AI (P < 0.001), Pog-a (smile) and Sn-a (rest) facial AI (P < 0.001), Nt-a (smile) and Sn-a (rest) facial AI (P < 0.001), Nt-b (smile) and Sn-b (rest) facial AI (P < 0.001), Ph-a (smile) and Sn-a (rest) facial AI (P < 0.001), Ph-b (smile) and Sn-b (smile) facial AI (P = 0.007), Oc-b AI (difference) and Gn-b (rest) facial AI (P = 0.031), Oc-Pog (difference) AI and Gn-b (rest) facial AI (P = 0.041), An-b (difference) AI and Sn-b (rest) facial AI (P < 0.001), Nt-a (difference) and Sn-a (rest) facial AI (P = 0.006), Nt-b (difference) and Sn-b (rest) facial AI (P < 0.001), and Ph-b (difference) and Sn-b (rest) facial AI (P < 0.001). CONCLUSIONS: A significant correlation exists between social smile symmetry and facial symmetry.

Pharyngeal airway dimensions in Iranian female young adults with different skeletal patterns using cone-beam computed tomography.

OBJECTIVES: To assess the oropharyngeal airway in Iranian female young adults with different skeletal patterns using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: This descriptive, cross-sectional study evaluated 105 CBCT scans of female patients between 18 and 35 years retrieved from the archives of a radiology clinic. The images were evaluated in axial, sagittal, and frontal sections. In the axial plane, the maximum and minimum cross-sectional area (CSA) of the airways at the oropharynx, minimum width (anteroposteriorly), and minimum depth (laterally) were measured using Mimics Medical software. The oropharyngeal volume was measured by NemoFAB software. The values were compared among the groups with different sagittal, vertical, and transverse patterns. The correlation of indices with airway measurements was analyzed using Monte Carlo Chi-square and Pearson's correlation coefficient. RESULTS: No significant difference was noted in oropharyngeal airway dimensions and volume among cases with different skeletal sagittal, vertical, and transverse patterns (P > 0.05) except for class III patients with normal transverse pattern in whom maximum CSA in low-angle group was larger than that in normal-angle group (P < 0.05) and class I normal-angle patients in whom maximum CSA in transverse normal group was smaller than that in constriction group (P < 0.05). CONCLUSIONS: Oropharyngeal dimensions were not significantly different in Iranian female young adults with different skeletal patterns.

Relationship between the amount of mesial movement of the mandibular first molar and angular changes of the mandibular third molar: A retrospective comparative study in growing patients with and without first premolar extraction.

OBJECTIVES: The main objective of this study was to assess the relationship of the amount of mesial movement of mandibular first molar (MFM) and angular changes of the mandibular third molar (MTM) in orthodontic patients. The secondary objective of this study was to compare the obtained values in extraction and non-extraction orthodontic patients. MATERIAL AND METHODS: In this cross-sectional retrospective study were enrolled all the eligible patients (12-16 years) with and without first premolar extraction that met the inclusion criteria. The angle between the longitudinal axis of MTM and horizontal reference plane (HRP) (to calculate the angular change of MTM), and the distance between the cementoenamel junction of the mesial surface of MFM and the bisector of the anterior nasal spine and nasal septum (to determine the amount of mesial movement of MFM) were measured on pre- and post-treatment panoramic radiographs. The correlation between the two variables was analysed and compared between extraction and non-extraction patients using STATA v. 14.2 software. RESULTS: A total of 100 fixed orthodontic patients with and without first premolar extraction (n=50) whose treatment had been accomplished were included in the study. In the non-extraction group, the mean amount of mesial movement of MFM was 1.45mm and the mean angular change of MTM was 4.28 degrees; this correlation was significant (P<0.05). These values were 2.98mm and 7.17 degrees in the first premolar extraction group, respectively, with a significant correlation (P<0.05). However, the difference in this respect was not significant between the two groups (P>0.05). According to the regression model, 1mm mesial movement of MFM would averagely cause 2.2-degree angular change in MTM, adjusting for the effect of extraction/non-extraction treatment plan. CONCLUSION: The mesial movement of MFM was significantly correlated with the angular changes of MTM in extraction and non-extraction orthodontic patients, with no significant difference between them.

Optimal gingival display on smiling based on different facial vertical patterns in Iranians.

INTRODUCTION: This study aimed to determine the optimal gingival display on smiling on the basis of different facial vertical patterns in Iranians from the perspective of laypeople, maxillofacial surgeons, and orthodontists. METHODS: Photographs were obtained from short-faced, normal-faced, and long-faced males and females (1 male and 1 female from each group) aged 18-30 years. The original photographs were then modified to have 6, 4, 2, 0, -2, -4, and -6 mm gingival display. Three groups of raters (n = 40), including laypeople, orthodontists, and maxillofacial surgeons, were requested to score each photograph regarding smile attractiveness using a 5-point Likert scale. Data were analyzed using analysis of variance and the Kruskal-Wallis test. RESULTS: Regarding the photographs of the normal-faced female model, all 3 rater groups gave the highest score to a 2 gingival display. In the normal-faced male model, all 3 rater groups gave the highest and lowest scores to 0 and 6 mm gingival display, respectively. In the long-faced female model, all 3 rater groups gave the same score to 0, 4, and 6 gingival display. In the long-faced male model, the 3 rater groups gave the same score to 0, 2, 4, and 6 gingival display. In the short-faced female model, all 3 rater groups gave the highest score to 0 gingival display. In the short-faced male model, the 3 rater groups gave the same score to all values of gingival display except -4 mm. CONCLUSIONS: The laypeople, maxillofacial surgeons, and orthodontists all gave the highest score to the photograph of a short-faced Iranian female model with 0 gingival display.

Effect of Continuous Positive Airway Pressure on Changes of Plasma/Serum Ghrelin and Evaluation of These Changes between Adults with Obstructive Sleep Apnea and Controls: A Meta-Analysis.

BACKGROUND AND OBJECTIVE: Obstructive sleep apnea (OSA) can be related to high ghrelin hormone levels that may encourage additional energy intake. Herein, a new systematic review and meta-analysis were performed to check the changes in serum/plasma levels of ghrelin in adults with OSA compared to controls, as well as before compared after continuous positive airway pressure (CPAP) therapy in adults with OSA. MATERIALS AND METHODS: Four main databases were systematically and comprehensively searched until 17 October 2022, without any restrictions. For assessing the quality, we used the Joanna Briggs Institute (JBI) critical appraisal checklist adapted for case-control studies and the National Institutes of Health (NIH) quality assessment tool for before-after studies. The effect sizes were extracted by the Review Manager 5.3 software for the blood of ghrelin in adults with OSA compared with controls, as well as before and after CPAP therapy. RESULTS: Fifteen articles involving thirteen studies for case-control studies and nine articles for before-after studies were included. The pooled standardized mean differences were 0.30 (95% confidence interval (CI): -0.02, 0.61; p = 0.07; I2 = 80%) and 0.10 (95% CI: -0.08, 0.27; p = 0.27; I2 = 42%) for case-control and before-after studies, respectively. For thirteen case-control studies, nine had moderate and four high qualities, whereas for nine before-after studies, five had good and four fair qualities. Based on the trial sequential analysis, more studies are needed to confirm the pooled results of the analyses of blood ghrelin levels in case-control and before-after studies. In addition, the radial plot showed outliers for the analysis of case-control studies that they were significant factors for high heterogeneity. CONCLUSIONS: The findings of the present meta-analysis recommended that the blood levels of ghrelin had no significant difference in the adults with OSA compared with the controls, nor did they have significant difference in adults with OSA before compared with after CPAP therapy. The present findings need to be confirmed in additional studies with more cases and higher qualities.

Efficacy of a smartphone application as an aid to enhance the instruction of radiographic differential diagnosis of maxillofacial bony lesions.

OBJECTIVES: The purpose of this study was to assess the efficacy of a smartphone application for instruction of radiographic differential diagnosis of maxillofacial bony lesions as an aid to enhance to traditional learning (lecture-based learning) for dental students. METHODS: This quasi-experimental study evaluated 50 fifth-year dental students who were randomly divided into two groups. The two groups were matched in terms of grade point average to ensure their equal baseline knowledge level. The experimental group (n = 25) received instructions regarding differential diagnosis of maxillofacial bony lesions via a self-designed smartphone application, while the control group (n = 25) received lecture-based instruction of the same topic. The students participated in a written exam (10 questions) immediately and 2 months after the interventions. Each question had 3 differential diagnosis choices. The best answer choice was allocated a score of 0.5, while other answer choices were allocated a score of 0.25. Data were analyzed using repeated measures ANOVA, and Mann-Whitney U and Wilcoxon tests. RESULTS: The mean score of the experimental group was significantly higher than that of the control group immediately after the intervention (p < 0.001) and also at 2 months (p < 0.001). The mixed effect linear model revealed that after controlling for the effect of age and sex, the mean score of the experimental group was still significantly higher than that of the control group immediately and at 2 months after the intervention (p < 0.001). CONCLUSIONS: Smartphone-based mobile learning can effectively enhance the knowledge and practical skills of dental students in differential diagnosis of maxillofacial bony lesions as an aid to enhance to traditional learning.

Effect of Serum Level of Vitamin D on External Apical Root Resorption in Maxillary Anterior Teeth in Patients under Fixed Orthodontic Treatment.

Introduction: This study aimed to assess the effect of serum level of vitamin D on external apical root resorption (EARR) in maxillary anterior teeth in patients under fixed orthodontic treatment. Materials and Methods: This retrospective cohort was conducted on patients under fixed orthodontic treatment who were between 12 to 30 years of age. All patients underwent the same treatment technique by the same orthodontist using a 0.022 MBT system. EARR in maxillary anterior teeth was evaluated on pre- and postoperative panoramic radiographs. Blood samples were also collected from patients, and their serum level of vitamin D was measured after the completion of treatment. Data were analyzed by independent t-test and Chi-square test (alpha = 0.05). Results: A reduction in root length was noted in all patients, which was significant (P < 0.0001); 75% of patients showed EARR in at least one maxillary incisor. EARR had no significant correlation with the serum level of vitamin D (P=0.423). Conclusions: Serum level of vitamin D had no significant correlation with the occurrence of EARR. However, the high prevalence of EARR calls for measures to minimize it.

Effect of zirconium oxide nano-coating on frictional resistance of orthodontic wires.

Objectives: Minimizing the frictional force between orthodontic wire and brackets is imperative to safely obtain a more favorable result by applying lower loads. Several methods have been proposed for this purpose such as changing the wire shape/size, changing the bracket design, and coating wires with different materials. This study aimed to assess the effect of zirconium oxide (ZrO2) nano-coating on frictional resistance of three types of orthodontic wires. Materials and Methods: This in vitro, experimental study evaluated 42 pieces of nickel-titanium (NiTi), stainless steel (SS), and beta-titanium (TMA) orthodontic wires, and 42 maxillary canine brackets. The samples were divided into six groups with and without ZrO2 nano-coating. The nano-coating was applied on the wires using the sol-gel technique. The presence of ZrO2 nano-coating was evaluated by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The surface roughness of the samples was evaluated using atomic force microscopy (AFM). The brackets and wire had a 5° angle relative to each other. The static and kinetic friction of the samples were evaluated in the presence of artificial saliva and occlusogingival movements in a universal testing machine. Data were analyzed by the Shapiro-Wilk's test, one-way ANOVA, Kruskal-Walli's test, Mann-Whitney U test, independent t-test, and Tukey's test. Results: ZrO2 nano-coating was only observed on TMA wires. The surface roughness of coated NiTi and SS wires had no significant difference from that of non-coated wires (P > 0.05). However, this difference was significant for TMA wires with and without the coating (P < 0.05). The static and kinetic friction were not significantly different between wires with and without coating (P > 0.05). Conclusions: ZrO2 nano-coating could only be applied on TMA wires, and had no significant efficacy for reduction of static or kinetic friction of TMA wires.

Assessment of Implant-Related Anatomical Landmarks in the Mandibular Interforaminal Region in an Iranian Population Using Cone-Beam Computed Tomography.

Background: This study was aimed to assess the implant-related anatomical landmarks in the mandibular interforaminal region in an Iranian population using cone-beam computed tomography (CBCT). Methods: In this retrospective cross-sectional study, 378 CBCT images of the mandible were evaluated for the presence of the incisive canal, anterior loop of the inferior alveolar nerve (IAN), mandibular canal, mental foramen, and incisive canal. The effect of age and gender of patients on the abovementioned variables was also evaluated. Data were analyzed using independent t-test, analysis of variance, and Chi-square test. Results: The anterior loop and the incisive canal were present in 36.24% and 97.62% of the cases, respectively. The mean length of the anterior loop and the incisive canal was 2.70 ± 1.20 mm and 12 ± 3.29 mm in the right, and 2.86 ± 1.24 mm and 12.21 ± 3.38 mm in the left side, respectively. The mean diameter of the mental foramen and incisive canal was 4.25 ± 1.08 mm and 1.89 ± 0.46 mm in the right, and 4.21 ± 1.02 mm and 1.94 ± 0.45 mm in the left side, respectively. The descending path was the most common path of the incisive canal. The distance from the incisive canal to the buccal plate and inferior border of the mandible was significantly shorter in females (P < 0.001). Conclusion: Considering the high variability and clinical significance of the incisive canal and anterior loop of the IAN, and their high prevalence, it is recommended to assess the presence/absence of these structures in the interforaminal region of the mandible on CBCT scans before surgical procedures in this region.

Efficacy of Photobiomodulation Therapy Versus Soft Acrylic Wafer for Reduction of Pain Associated with Orthodontic Metal Bracket Removal: A Clinical Trial.

Objective: This study compared the efficacy of photobiomodulation therapy versus soft acrylic wafer for reduction of pain associated with orthodontic metal bracket removal. Background: It has been demonstrated that different methods of bracket removal are associated with different levels of pain. Photobiomodulation decreases the level of pain due to its biological effects. Methods: This split-mouth randomized clinical trial evaluated 28 orthodontic patients. The four quadrants in each patient were randomly assigned to four groups of diode laser (940 nm, 31.7 J/cm2 energy density, 1.7 cm2 spot size, 300 mW power, continuous-wave, contact mode) irradiated to the buccal and palatal surfaces of each tooth, soft acrylic wafer, laser in off mode (placebo), and no intervention (control). The severity of pain experienced by patients was assessed immediately after bracket removal from each tooth using a visual analog scale. Data were analyzed using the generalized estimating equation (α = 0.05). Results: The mean pain score in the soft acrylic wafer (p = 0.017), control (p < 0.001), and placebo (p < 0.001) groups was significantly higher compared with the laser group. Gender (p = 0.209), age (p = 0.095), and laterality (right/left quadrant; p = 0.383) had no significant effect on the pain score. The pain score in the mandible was significantly lower compared with the maxilla (p = 0.027). The first and second premolars had significantly lower pain scores (p < 0.05). Conclusions: Within the limitations of this study, photobiomodulation therapy and soft acrylic wafer can both decrease the pain associated with metal bracket removal, but laser is more effective.

Survival analysis of three types of maxillary and mandibular bonded orthodontic retainers: a retrospective cohort.

BACKGROUND: Retention is an important aspect of orthodontic treatment. This study aimed to analyze the survival of three types of maxillary and mandibular bonded orthodontic retainers. METHODS: This retrospective cohort study evaluated the records of 118 orthodontic patients (90 females, 28 males, mean age of 22.34 ± 6.44 years) retrieved from a private orthodontic office. Data regarding the retainer failure, dental caries, unwanted tooth movements, maximum pocket depth (PD), and bleeding on probing (BOP) recorded at the follow-up sessions were extracted from patient records. Three types of retainer wires namely Bond-A-Braid, Orthoflex, and Retainium were compared regarding the abovementioned parameters. Data were analyzed by ANOVA, Chi-square, Monte-Carlo Chi-square, and Kruskal Wallis tests, the log rank test, and the Cox regression model. RESULTS: The frequency of retainer failure was not significantly different between males and females, different age groups, or different treatment durations (P > 0.05). Wire fracture was the most common failure type in both the maxilla and mandible. Also, the frequency of failure was not significantly different between the maxillary and mandibular retainers (P > 0.05). The frequency of failure, and survival of the three types of retainer wires were not significantly different during a 5-year period (P > 0.05). CONCLUSIONS: The three types of orthodontic retainers had comparable survival rates. Their failure rate was not correlated with the age or gender of patients or the treatment duration.

Comparison of the Type and Severity of Nasal Septal Deviation between Chronic Rhinosinusitis Patients Undergoing Functional Endoscopic Sinus Surgery and Controls.

Objectives: Some correlations have been proposed between chronic rhinosinusitis (CRS) and type and severity of nasal septal deviation. This study sought to compare the type and severity of nasal septal deviation between CRS patients undergoing functional endoscopic sinus surgery (FESS) and asymptomatic controls using cone-beam computed tomography (CBCT). Materials and Methods: This prospective case-control study evaluated 49 CRS patients who did not respond to pharmaceutical therapy and were candidates for FESS and 49 asymptomatic controls. All participants underwent CBCT and were inspected for septal deviation type and severity. Data were analyzed by the independent t-test and chi-square test. Results: The study population comprised of 58.25% males and 41.8% females, with a mean age of 33.74 ± 11.78 years. Significant correlations were noted between the presence of CRS and severity of septal deviation (P=0.007). Type of septal deviation had no significant correlation with the presence of CRS (P=0.443). Conclusion: Patients with CRS have significantly more severe nasal septal deviation. However, type of septal deviation is not correlated with CRS.

Assessment of the Asymmetry of the Lower Jaw, Face, and Palate in Patients with Unilateral Cleft Lip and Palate.

Background: This study aimed to assess the asymmetry of the lower jaw, face, and palate in patients with unilateral cleft lip and palate (UCLP) using photography, cone-beam computed tomography (CBCT), and digitized three-dimensional casts. Methods: This case-control study was conducted on photographic, CBCT, and digital cast records of 14 UCLP patients and 24 healthy controls between 10 and 16 years. Totally, 65 variables were measured on photographs, CBCT scans, and on digitized casts. Measurements were compared between the two groups and within each group between the two sides. For easier measurement, in patients who had right side CLP, the cleft was transferred to the left side and in subjects without cleft, mild chin deviation was transferred to the left side. Results: The anteroposterior dimensions of the two condyles in the UCLP group were greater than those in the control group, while the mediolateral dimensions of the left condyle and ramus height, mandibular body length, and total length of the mandible in the control group were greater than those in the UCLP group. Right ocular, nasal, and angular variables were greater in the UCLP group. Other variables except for the palatal width from the right canine to midline were greater in the control group. Conclusion: Our findings highlighted the presence of asymmetry in the nasal and palatal areas in patients with UCLP while these patients had no significant difference with healthy controls in the relationship of condyles with the temporomandibular fossa.

Correlation of Ponticulus Posticus with Dentofacial Skeletal Patterns.

Background: This study aimed to assess the correlation of ponticulus posticus (PP) with dentofacial skeletal patterns on lateral cephalograms of an Iranian population. Methods: This retrospective study evaluated 1000 lateral cephalograms of 690 females and 310 males. Demographic information of patients was recorded, and two observers evaluated all radiographs for the presence of PP. The dentofacial skeletal pattern was also determined as Class I, II, or III. Disagreements were resolved by discussion with a third observer. Data were analyzed using the Chi-square test. Results: The mean age of patients was 19.47 ± 8.37 years (range 7-64 years). The prevalence of PP was 38.3%. PP had a significant correlation with gender (P = 0.022) such that PP was more common in males (43.5%). No significant correlation was noted between PP and age or dentofacial skeletal pattern (P > 0.05). Conclusions: PP was relatively common in our study population. PP had no correlation with age or dentofacial skeletal pattern of patients.

Bond Strength and Deflection of Four Types of Bonded Lingual Retainers.

OBJECTIVES: This study aimed to assess the bond strength and deflection of four types of bonded lingual retainers. MATERIALS AND METHODS: In this in vitro, experimental study, 160 extracted, mandibular incisors were mounted in acrylic blocks in sets of two and randomized into four groups for bonding of 1.0.010 × 0.026-inch Bond-A-Braid®, 0.012 × 0.027-inch Retanium®TM, 0.038 × 0.016-inch Ortho FlexTech®, and 0.0175-inch three-strand retainer wires; 15 mm of passive wire was adhered to the lingual tooth surface using Transbond XT composite. The shear (SBS) and tensile (TBS) bond strength values were measured. The adhesive remnant index (ARI) score and deflection of wires were also determined under a stereomicroscope. Data were analyzed by the chi-square test and ANOVA. RESULTS: The four groups were significantly different regarding the ARI scores (P < 0.05). Significant differences were noted between the three-strand and all other groups in deflection (P < 0.05). The Retanium group had significant differences with other groups in peak SBS (P < 0.05). A significant difference was found between the Retanium and Ortho Flex groups in break SBS (P < 0.05). Significant differences were also reported between the three-strand and all other groups in peak TBS (P < 0.05). CONCLUSION: The Retanium retainer had the maximum SBS, while the three-strand retainer had the maximum TBS. The three-strand and Retanium wires can probably better tolerate intraoral forces and have higher resistance to fracture due to having higher TBS. Also, the three-strand wire had lower deflection rate, which highlights its higher resistance to occlusal forces. Retanium and Ortho FlexTech wires had the most favorable failure modes.

Effect of Caffeine Injection on Orthodontic Tooth Movement in Rats: An Experimental Study on Rats.

OBJECTIVES: Several studies have investigated the effects of different medications on orthodontic tooth movement (OTM). This study assessed the effect of caffeine injection on OTM in rats. MATERIALS AND METHODS: Thirty-five male Wistar rats were randomly divided into five groups. Their first molars and central incisors were attached with a nickel-titanium closed coil spring with 50 g load. The rats in the three experimental groups received 25, 50, and 75 mg/kg caffeine intraperitoneally for 21 days. The negative control group did not receive any injection and did not undergo orthodontic treatment. The positive control group underwent orthodontic treatment and received 0.9% NaCl (saline) injection. After 21 days, all rats were sacrificed by chloroform inhalation, and the maxilla was resected. The mean number of Howship's lacunae, blood vessels, osteoclasts, and root resorption lacunae was histologically measured. The bone volume-to-total volume ratio (BV/TV) in maxillary molars was calculated by microcomputed tomography (micro-CT) to quantify bone loss. RESULTS: The amount of OTM and the number of osteoclasts, blood vessels, and Howship's lacunae significantly increased in rats under caffeine therapy, while the number of root resorption lacunae did not increase. Lower BV/TV in the caffeine groups was in accord with the increased count of osteoclasts. CONCLUSION: Caffeine injection can significantly increase OTM in rats.

A Randomized Triple-Blind Clinical Trial of the Effect of Low-Level Laser Therapy on Infiltration Injection Pain in the Anterior Maxilla

Abstract Objective: To evaluate the level of pain experienced during infiltration anesthesia of the anterior maxilla following low-level laser therapy (LLLT) with 810-980 nm wavelengths. Material and Methods: In the current triple-blind clinical trial, 84 patients received a total of 168 infiltration anesthesia injections (1.8 mL of 2% lidocaine plus 1:100,000 epinephrine) in the anterior maxilla. Each patient received two injections into the buccal mucosa of the right and left central incisors with a two-week interval. One injection was performed after LLLT, while the other injection was administered conventionally without laser. The pain level was measured immediately after injection using a visual analog scale (VAS). Results: There was a significant difference in the pain level experienced with and without LLLT, such that the mean pain score following LLLT was significantly lower than that without LLLT (p<0.05). No significant difference was found in the pain level between laser and no laser groups in males, but the difference in this regard was significant in females (p<0.05) and female patients experienced a significantly lower level of pain following LLLT. Conclusion: The low-level laser therapy can be successfully used to decrease the level of pain experienced during infiltration anesthesia of the anterior maxilla (AU).

Effect of Methotrexate Injection on Orthodontic Tooth Movement: An Experimental Study on Rats.

INTRODUCTION: Knowledge about the effects of medications, vitamins, and various supplements on orthodontic tooth movement (OTM) is imperative for orthodontists. This study aimed to assess the effect of methotrexate (MTX) injection on OTM in rats. MATERIALS AND METHODS: Twenty-eight male Wistar rats were randomized into four groups (n = 7). The first molar and central incisor were connected using a nickel-titanium (NiTi) coil spring with a 50 g load in each rat. The two experimental groups received 0.75 mg/kg and 1.5 mg/kg MTX, respectively, intraperitoneally for 21 days. The negative control group did not receive any injection and did not undergo orthodontic treatment. The positive control group underwent orthodontic treatment and received 0.9% saline (NaCl) injections for 21 days. All rats were sacrificed with chloroform inhalation after 21 days; their maxilla was resected, and the mean number of Howship's lacunae, blood vessels, osteoclasts, and resorption lacunae was counted. The reduction in bone volume (bone volume to total volume ratio (BV/TV)) at the site of the maxillary molar was quantified by microcomputed tomography (micro-CT). RESULTS: OTM, the number of osteoclasts, and the number of blood vessels significantly increased in rats treated with MTX (P < 0.05). However, the increase in the number of Howship's lacunae and resorption lacunae was not significant (P > 0.05). Lower BV/TV in the MTX groups was in agreement with the increased number of osteoclasts. CONCLUSION: Injection of MTX can significantly increase OTM and decrease root resorption in rats.