Iranian Journal of Orthodontics
Volume:17 Issue: 1, Jun 2022

Droplets and aerosols are the main source of transmission and rapid spread of COVID-19 worldwide. Topical mouthwashes and oronasal irrigation are recommended as ways of preventing airborne transmission to health care professionals. This meta-analysis aimed to assess the changes of COVID 19 viral load after administration of different mouthwashes.

An electronic search was undertaken including the following databases: Medline/PubMed, Web of Science, Scopus, and Embase. Search for grey literature, and hand search for relevant studies was also performed. The quality of included randomized clinical trials (RCTs) were assessed using the Cochrane Collaborations. Afterward, the relevant data from the included studies was extracted. Inverse-variance random-effects meta-analysis was performed to compare the effects of different types of mouthwashes on COVID viral presence.

After screening 1437 studies, 10 randomized clinical trials were finally selected. A total of 884 patients were assessed in these studies. The meta-analysis revealed the Cyclic Threshold (CT) values increased after the use of mouthwashes (MD=2.00, 95%CI= 0.51, 3.49, P<0.05). Considering the CT values are inversely correlated to the viral load, the result means the use of mouthwashes decreases the viral load in the saliva. This study also showed that increase of CT values was statistically significant for Povidone Iodine mouthwash (MD=4.08, 95%CI= 0.13, 8.02, P<0.05); however, Cetylpyridinium Chloride and Chlorhexidine Gluconate mouthwashes non-significantly (P value>0.05) reduced viral load in the saliva of patients with COVID 19.

According to the result of this study, the use of mouthwashes reduces the viral load of saliva in patients with COVID 19. In addition to basic precautions for preventing the transmission of COVID 19, using mouthwashes may be a reasonable way to decrease the risk of disease transmission to medical staff.

The aim of this study was to analyze and synthesize data from animal research on the impact of hormones and their synthetic derivatives on orthodontic tooth movement by altering calcium metabolism.

Eight databases were scanned electronically, followed by a manual search, until 27 February 2022. Animal experiments were chosen with control groups exploring the impact on orthodontic tooth movement with calcitonin, calcium, parathyroid hormone, teriparatide, and vitamin D. The reporting quality of primary studies was assessed using the CAMARADES tool. Data was collected from related studies and SYRCLE’s risk of bias tool was utilized to determine risk of bias.

Of the 2388 documents obtained in the search, 11 studies were included. The amount of orthodontic tooth movement reduced with the administration of calcitonin and calcium. However, with parathyroid hormone, teriparatide, and vitamin D, acceleration of tooth movement was noted. The results were statistically significant omitting three studies that assessed orthodontic tooth movement with calcium, vitamin D, and parathyroid hormone. Root resorption increased with calcium, vitamin D, PGE2, and a dose-dependent decrease was seen in higher doses of calcitonin. Bone mineral density improved with increased parathyroid hormone levels.

Vitamin D, their synthetic derivatives, and parathyroid hormone were found to increase orthodontic tooth movement. Calcitonin showed a dose dependent reduction in orthodontic tooth movement.

The use of pre-procedural mouth rinse for prevention of COVID-19 can reduce viral load but can alter the bond strength. The purpose of this study was to determine any correlation between the use of these pre-procedural mouth rinse and the shear-bond strength (SBS) of orthodontic brackets.

Thirty-three maxillary premolars extracted for orthodontic purposes were used. The buccal surfaces of all teeth were bonded with orthodontic brackets. Later, each tooth was embedded into acrylic resin and stored in distilled water. Teeth were randomly divided into three groups (group I: hydrogen peroxide mouth rinse, group II: povidone-iodine mouth rinse, and group III: artificial saliva), and stored in each solution for 12 hours. Later, each tooth was subjected to SBS testing using a universal testing machine. Data were statistically evaluated using one-way analysis of variance (ANOVA) and post hoc test (Tukey’s HSD) with a significance of p< 0.05.

The highest mean SBS was observed in the artificial saliva (control group), followed by the povidone-iodine and hydrogen peroxide groups.

Hydrogen peroxide mouth rinses should not be used during fixed orthodontic treatment because it alters bond strength.

This study aims to compare the shear bond strength (SBS) of different combinations of retainer wires and enamel preparation methods.

A total of 180 extracted mandibular bovine incisors were randomly divided into nine groups of 20 paired teeth each. Three techniques were employed to prepare the enamel: acid etches only, Er:YAG laser before acid etch, and sandblast before acid etch. The retainer wires, including Bond-A-Braid, GAC Wildcat Twistflex Wire, and TruForce coaxial wire, were bonded with the adhesive Transbond LR and SBS values were measured. The two-way ANOVA test was used to evaluate the effect of the conditioning method in combination with the retainer wire type and the interaction of two variables. Pairwise comparisons were done using the Tukey post hoc test. A value of P≤0.05 was considered to be significant for all statistical tests.

The highest shear bond strength value was found for sandblasted surface bonded with Bond-A-Braid wire. The combination of acid-etched enamel/GAC Wildcat Twistflex wire revealed the lowest value of the SBS. Statistically significant differences did not exist for the Adhesive Remnant Index (ARI) scores among the study groups.

Sandblasting and laser irradiation before the acid etching significantly increased the SBS. Differences in the SBS values of different wires were insignificant.

This study compared the prevalence of tooth agenesis out of the cleft area in patients with complete bilateral cleft lip and palate (BCLP) with and without agenesis of maxillary permanent lateral incisors.

Tooth agenesis was evaluated in panoramic radiographs taken between 7 and 11 years of age. Intergroup comparison of tooth agenesis frequency was performed using the chi-square test (P<0.05) and the odds ratio. A sample of 130 patients (87 male, 43 female) with non-syndromic bilateral cleft lip and palate was selected. Group P (n = 44) consisted of individuals with the presence of maxillary lateral incisors on the right and left sides; group UA (n = 40) comprised patients with unilateral agenesis of lateral incisors; group BA (n = 46) comprised patients with bilateral agenesis of lateral incisors. Intergroup comparison for frequency of tooth agenesis outside the cleft area was performed using Chi-square test (p-value <0.05 was considered significant) and the odds ratio (p<0.016).

The prevalence of dental agenesis out of the cleft area in groups P, UA, and BA was 31.8%, 32.5%, and 60.8%, respectively. Group BA showed a significantly greater prevalence of tooth agenesis compared with the UA and P groups. There was no significant difference in the odds ratio between any groups. The most common absent teeth were the maxillary second premolars followed by the mandibular second premolars for all groups.

Patients with BCLP and bilateral agenesis of maxillary lateral incisors show an increased prevalence of other permanent teeth. This association demonstrates a genetic background of maxillary lateral incisor agenesis at the cleft area.

The objective of this study was to compare tooth movement using platelet-rich plasma (PRP) and the conventional method in patients with moderate crowding during the leveling and aligning phase.

Fifty patients with moderate crowding in the maxillary arch were chosen. Split-mouth design was planned with one quadrant allotted as the experimental group (PRP side) and the other as the control group. Five injection sites were pre-defined: distal surface of the root of the central incisor, mesial and distal root surfaces of the lateral incisor and canine. After the extraction of the permanent maxillary first premolars, PRP was injected at various sites on the experimental side while the other side served as the control group. In each group, four times were studied: 0(T0), 21(T1), 42(T2), and 63(T3) days after injection. Tooth movement was measured using a digital vernier caliper and statistical analysis was done using paired t-test.

Significant amount of tooth movement was seen at 21 days (p<0.001). No significant difference in tooth movement was found at 42 days (p=0.265) and 63 days (p=0.104) after injection.

Platelet-Rich Plasma is responsible for accelerating orthodontic tooth movement in patients with moderate crowding when injected during the leveling and aligning phase for the first 21 days after injection although it was non-effective after 42 and 63 days.

With the increased use of cone beam computed tomography (CBCT) scans in orthodontic diagnosis and treatment planning, validation of using radiographic images obtained from CBCT instead of multiple conventional radiographs is needed.  Hence, the present study was designed to assess the differences between cephalometric measurements taken from manual tracings (MT), digitized lateral cephalograms (DLC) and CBCT lateral cephalograms scans

Conventional lateral cephalograms and CBCT scans from ten subjects from departmental archives were used to assess the three

manual tracings, digitized lateral cephalograms, and CBCT lateral cephalograms. Seventeen measurements were evaluated and retraced after a 7-day period. The intra examiner errors was assessed using the paired t test and Dahlberg formula. The Pearson correlation test and ANOVA test evaluated the differences between the methods.

Most of the measurements had intra-examiner reliability in all three methods. Measurements were significant among methods were Y-axis, U1-Apog (degree and mm), U1-NA, L1-NB (degree and mm), L1-Apog, and interincisal angle.

All three methods proved to be reliable and reproducible with minimum error in the measurement of lateral cephalograms. The CBCT scan, advised for complex cases, can be used to generate lateral cephalogram images, which may reduce the need for multiple radiographs, thereby reducing radiation exposure and cost.

Among various retraction methods for space closure in first premolar extraction, the palatal approach is preferred to labial appliances in cases having high aesthetic demand. A finite element model and clinical randomized prospective trial was undertaken to determine the possibility of en-masse retraction of maxillary anterior teeth using palatal TAD and a clear aligner-like appliance in patients undergoing extraction of maxillary first premolars and to study the effects of the above using three-dimensional scanned models and lateral cephalograms.

A finite element model of maxillary dentition with alveolar bone, an acrylic splint on six anterior teeth, palatal implants, and short e-chain were produced to measure shifting when force was applied from three various levels. Thereafter, the finite element analysis findings were applied to 10 patients requiring fixed orthodontic treatment with first premolar extraction and fulfilling the inclusion criteria. Impressions were made and the rate of retraction was evaluated at 4-week intervals by superimposition of scanned models.

En-masse bodily retraction was seen when both canine hooks and palatal TAD was placed at 10 mm distance from the respective gingival margin. Clinically, subjects showed significant retraction at that level and statistically significant results in some cases. The maximum rate of retraction was seen in the first three months (average: 5.310 mm) with p-value <0.0001.

Translational tooth movement was observed when line of force was at the level of the center of resistance.

Frankfurt horizontal and Sella-Nasion lines are the most widely accepted and used landmarks in cephalometric analysis. This study investigates the use of the Orbito-Condylion line extending from the Orbitale to the Condylion as a novel horizontal line for substituting the Frankfurt horizontal line. Similarly, the evaluation of the Orbito-Basion line as an alternative to the Sella-Nasion line in cephalometric analysis was done. We evaluated the reproducibility of the new horizontal lines and measured the angle between the Orbito-Condylion line and the Frankfurt line; and the angle between the Sella-Nasion and Orbitale-Basion line.

This investigation was carried out on 30 individuals. The Porion, Orbitale, Condylion, Sella, Nasion, and Basion were identified and marked. The angles between the orbito-meatal line (inferior orbital rim to the Porion; the Frankfurt line) and the Orbito-Condylion line (inferior orbital rim to the Condylion) were measured. Likewise, the angles between the Sella-Nasion line (center of sella tursica to Nasion) and the Orbito-Basion line (inferior orbital rim to Basion) were measured.

Significant interobserver and intraobserver bias did not exist. The mean angle between the Frankfurt line and Orbito-Condylion line was 0.5°±2.27° and the mean angle between the Sella-Nasion line and Orbito-Basion line was 3.48°±3.11°.

This study showed the new lines have good reproducibility, reliability, and efficacy. The Orbito-Condylion and Orbito-Basion lines are reliable, reproducible, and easily identifiable, and has the potential as novel standard horizontal lines to supersede or complement the Frankfurt line and Sella-Nasion line in anthropological studies and clinical applications.

The purpose of this in-vivo study is to determine and compare the accuracy of dental measurements calculated on physical and digital models with the measurements taken directly from the patients’ mouth.

This study was performed on 40 subjects. Forty maxillary impressions were produced using a condensation silicone putty material and constructed into a physical model. A digital vernier caliper was utilized to take direct measurements from the patients’ mouth as well as from the physical models. CS 3600® was employed for direct intra-oral scanning for the subjects’ dentition and generating the digital model. Three-dimensional reverse engineering software was used to make measurements on the digital model. One-way ANOVA test was used to determine the accuracy between the control group, physical models, and virtual group. Tukey’s post-hoc analysis was done to compare between the individual group.

There were no statistically significant differences between the physical (p-value=0.254) and virtual models (p-value = 0.168) as compared to those measurements taken directly from the mouth.

The results of the current study demonstrate that intraoral scans are clinically sound to be used in diagnosis and treatment planning in dentistry and provide a professional and well-grounded substitute to the use of conventional plaster models.

The aim of the in vitro study was to examine the enamel surface after the application of four different methods for adhesive removal following the bracket debonding procedure, as well as to compare their effects on enamel surface.

Premolars (n=60) were randomly assigned to four groups. After initial debonding and recording the shear bond strength (SBS), adhesive remnant index (ARI) scores were assessed. The removal method for each of the four groups was the use of 1) a round bur, 2) rubber wheel bur, 3)12 fluted tungsten carbide bur, and 4) scaler. After that, teeth in all four groups were kept in artificial saliva for one month. After rebonding with a new bracket, again the SBS and ARI scores were measured. Two representative samples from each group were examined under a scanning electron microscope. ……. P-value <0.05 was considered as significant. ANOVA test was used to assess the SBS association within the group. Paired T test was used to assess the SBS between the group. fisher’s exact test was performed to compare ARI index before and after.

There was significant decrease in secondary SBS value in group 1 but significant increase in secondary SBS value in group 3, and a slight decrease in SBS value in group 4. In SEM images, there were composite remnants in all the four groups with fewer remnants in group 2. Enamel surface damage was observed in the SEM image of group 3. ARI scores showed no significant difference.

Adhesive remnant removal efficiency of the round bur and scaler are less. Rubber wheel bur is a good choice of instrument for removal of adhesive remnants from tooth surface as it does not affect the bond strength. Tungsten carbide bur shows good results, as secondary bonding SBS value increased. Significant difference between ARI scores did not exist, indicating a higher number of mixed type failure in all groups.

The aim of this study was to assess perception of students on the educational environment of Mashhad Dental School using the DREEM questionnaire.

In this cross-sectional study, 427 DREEM questionnaires were completed by dental students attending Mashhad Dental School during the academic year of 2020-2021. The questionnaire contained five different domains including: student perceptions of learning, student perceptions of teachers, student academic self-perception, student perception of the educational atmosphere, and students social self-perception. The overall score and the scores of each domain of the DREEM questionnaire were then compared among the students. Independent t-test and Mann-Whitney test were used for statistical analysis. P<0.05 was set as significant.

Both the total score and the score of each domain of the DREEM questionnaire were all less than 2. Comparing the mean scores of each domain, basic sciences students had significantly higher scores in the “student perception of learning” domain than clinical sciences students. The mean overall score of DREEM and each domain were not significant between the two sexes. There were no questions in the "acceptable" status, 36 questions were in the "problematic”, and 14 were “in need of attention” status.

This study showed that students attending the Mashhad Dental School do not have a positive perception of the educational environment. Therefore, more coherent educational planning is required to improve the quality of the educational environment.