Does surface enamel composition and characteristics vary with inter proximal enamel reduction?

OBJECTIVE: This study aimed to evaluate the chemical composition of the proximal enamel surface and the surface characteristics subjected to different extents of interproximal reduction (IPR) in a clinical setting. MATERIALS AND METHODS: Premolars of orthodontic patients which were designated for extraction were subjected to .2 mm, .3 mm, and .5 mm of IPR. After 1 month, the teeth were extracted and the teeth were subjected to scanning electron microscope (SEM) and energy-dispersive x-ray spectroscopy (EDX). RESULTS: The SEM images of the three experimental groups (taken at magnification of 500 × and 2000 ×) showed that the enamel surfaces were irregular and rough compared to the honey comb appearance of the unstripped group. Small areas of erosion of enamel surface were seen in Group I (0.2 mm) under 2000 × magnification compared to Group IV (control) which showed typical arrangement of enamel rods in alternating orientation. The enamel surfaces of stripped and unstripped enamel contained calcium, phosphorus, carbon, oxygen, and nitrogen. The differences were not statistically significant and neither were the calcium phosphorous stoichiometric ratios between the four groups. CONCLUSIONS: On analyzing the surface characteristics of enamel using SEM between the stripped and unstripped surfaces, there were irregularities and roughness seen in stripped surface whereas honey comb pattern was observed in unstripped enamel surfaces. The elements found in unstripped and stripped enamel surfaces were calcium, phosphorous, carbon, oxygen, and nitrogen. Although the calcium and phosphorus were high in the 0.5 mm IPR group, the difference between stripped and unstripped enamel surfaces was statistically not significant. CLINICAL RELEVANCE: There have been concerns that IPR can remove the superficial mineral-rich layer making the deeper layers more susceptible to carious attack. No study has evaluated the mineral content in different layers of enamel in response to IPR in vivo and this study found no significant difference between pristine enamel and enamel subjected to IPR. The results of this study strengthen the validity of the clinical protocol employed.

Post-treatment stability, survival time and periodontal health associated with vacuum-formed, bonded and rapid prototype retainers: A prospective clinical study.

BACKGROUND: New technologies have paved the way for newer fabrication techniques, such as rapid prototyping, which has gained popularity in the fabrication of several orthodontic appliances including retainers. AIM: To evaluate the stability, survival time and periodontal health associated with vacuum-formed retainers (VFRs), bonded retainers (BRs) and rapid prototype retainers (RPRs) over a period of 12 months in retention. STUDY DESIGN: Prospective clinical study. METHODS: A total of 72 participants completing fixed orthodontic treatment were allocated to the following three groups by the investigators based upon their initial malocclusion, compliant and preferences: VFR; BR; and RPR. The primary outcome was Little's Irregularity Index (LII). Other stability parameters, including arch length (AL), inter-canine width (ICW) and inter-molar width (IMW), were also assessed immediately after debonding (T0) and 12 months (T2) after debonding. In addition, survival time, and calculus index and gingival index (GI) were assessed. RESULTS: LII showed a significant difference (P = 0.00) between the groups and was increased in the VFR group (0.18 ± 0.22 mm) compared to the BR (0.03 ± 0.05 mm) and RPR (0.01 ± 0.03 mm) groups but was not clinically significant. The mean survival time of maxillary retainers was longest for the RPR group (220.63 days; 95% confidence interval [CI] = 194.1-247.16) but there was no significant difference between the three groups (P = 0.43). The mean survival time of mandibular retainers was higher and the same for the VFR and RPR groups (240 days; 95% CI = 240-240) and there was no significant difference between the three groups (P = 0.38). The calculus index score (P = 0.00) was statistically significant between the groups, with an increased score for the BR group (0.33 ± 0.27) compared to the VFR (0.07 ± 0.16) and RPR (0.13 ± 0.22) groups. Similarly, the GI score (P = 0.02) was statistically significant between the groups and was increased in the BR group (0.01 ± 0.19) compared to the VFR (-0.15 ± 0.18) and RPR (-0.06 ± 0.15) groups. The increase in calculus index and GI scores for the BR group were not clinically significant. CONCLUSION: There were no clinically significant differences between the three retainer groups in terms of stability, periodontal health and time to failure.

Comparative evaluation of physical and mechanical properties of clear aligners - a systematic review.

INTRODUCTION: The clinical effectiveness of clear aligners depends on the material properties both physical and mechanical. The purpose of this systematic review is to evaluate the physical and mechanical properties of different clear aligner materials and changes in the same during and after intra-oral use. METHODS: Search was done in five electronic databases: Pubmed, Embase, Scopus, Web of Science and Ovid individually by two reviewers. In vivo, Ex vivo and In vitro studies that evaluated the physical and mechanical properties of clear aligner materials were selected. The risk of bias assessment was performed using a modified Cochrane risk of bias tool. RESULTS: From the 24 articles selected, 19 evaluated a single physical property and 23 articles evaluated a single mechanical property of clear aligner materials. All domains in the risk of bias assessment showed low risk of bias except for 'blinding of outcome' which was unclear in almost all the selected studies. Properties such as hardness, optical properties, stiffness, and yield strength were found to be different for different clear aligner materials and were found to change with thermoforming, with intra-oral aging, and in simulated intraoral conditions. Due to heterogenicity in the parameters used to assess physical or mechanical properties a meta-analysis could not be done. CONCLUSIONS: Properties like hardness, color, stiffness, stress relaxation and creep behavior were different for various clear aligner materials and were found to deteriorate with thermoforming and intra-oral aging. Polyurethane-based materials have a higher level of hardness and stiffness but exhibit increased creep and stress relaxation properties. PROSPERO REGISTRATION NUMBER: CRD42021269597.

Prevalence, etiology, clinical features and management associated with impacted and transmigrated mandibular canines: a systematic review.

BACKGROUND: The occurrence of mandibular canine impaction and/ or transmigration is a rare clinical entity but diagnosis and treatment planning is of clinical significance. The associated etiological factors and the clinical guidelines for the management are still not clear. The aim of this systematic review was to summarize the available data to report the prevalence and identify the etiological factors, clinical features, and various treatment outcomes in patients with mandibular canine impaction and/or transmigration. METHODS: The review protocol was registered in PROSPERO (CRD42021222566) and was conducted and reported according to the PRISMA and Cochrane Handbook / Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. A computerized search of studies published up to April 30, 2023, was conducted using the following databases: Medline, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Scopus, Web of Science, and Latin American and Caribbean Health Sciences Literature. A manual search of the reference and citation lists of eligible articles and existing systematic reviews for any additions were also conducted. The Newcastle-Ottawa Scale quality assessment tool was used to assess the studies' quality. RESULTS: After removing 6 duplicates, 3700 articles were identified. For the final analysis, 19 studies published between 1985 and 2023 met all the eligibility criteria and were included. A total of 7 studies presented as good and 12 studies presented as satisfactory. Patients were screened in ten studies and diagnostic records from archives were retrieved in nine studies. The total number of diagnostic records screened was 138.394, and the total number of patients from the included studies was 43.127. CONCLUSIONS: Based on the findings from this systematic review, the prevalence of mandibular canine impaction ranged from 0.008% to 1.29% while canine transmigration from 0.12% to 0.98%. Crowding of the mandibular arch, the presence of a retained deciduous canine, and odontoma or cyst are the etiological factors more commonly associated with mandibular canine impaction and or transmigration. Surgical extraction and surgical exposure followed by orthodontic traction are the two most frequently carried out treatment modalities in the management of mandibular canine impaction and or transmigration.

Impact of oral appliance therapy on quality of life (QoL) in patients with obstructive sleep apnea - a systematic review and meta-analysis.

PURPOSE: Treatment of patients with obstructive sleep apnea (OSA) using mandibular advancement appliances enhances the airway and may be an alternative to continuous positive airway pressure (CPAP) in individuals with reduced adherence to CPAP therapy. The effectiveness as well as improved patient compliance associated with these appliances may improve the quality of life in patients with OSA. The aim of this systematic review of studies was to determine the improvement in quality of life amongst patients with OSA who were treated with an oral appliance. METHODS: The research study was registered on the International Prospective Register of Systematic Reviews (PROSPERO: CRD42021193386). A search was carried out using the search engines Google Scholar, PubMed, Ovid, Cochrane Trial Registry, and LILACS. Patients with OSA treated with oral appliance therapy to advance the mandible were studied. Twenty-five studies were identified through the literature search and all had varying control groups for assessment of quality of life. Seventeen studies were included for the quantitative synthesis. RESULTS: QoL, evaluated by the Functional Outcomes of Sleep Questionnaire (FOSQ), significantly improved in patients treated with oral appliance therapy. There was a mean difference of 1.8 points between the baseline scores and the scores following treatment with an oral appliance. CONCLUSION: Overall, a significant improvement in the QoL was observed with the Functional Outcomes of Sleep Questionnaire, following oral appliance therapy.

Evaluation of titanium dioxide coating on surface roughness of nickel-titanium archwires and its influence on Streptococcus mutans adhesion and enamel mineralization: A prospective clinical study.

INTRODUCTION: This research aimed to evaluate the effect of titanium dioxide (TiO2) coating on surface roughness (Ra) of nickel-titanium (NiTi) archwires and its influence on Streptococcus mutans (S mutans) adhesion and enamel mineralization at the end of 1 month in orthodontic patients and to evaluate the integrity of the TiO2 coating. METHODS: Twelve patients undergoing orthodontic treatment with preadjusted edgewise appliance formed the sample for this prospective clinical study. Uncoated NiTi archwires and TiO2 nanoparticle coated NiTi archwires in as-received condition and after 1 month of intraoral use were subjected to Ra analysis using surface profilometry, and surface topography using scanning electron microscopy. S mutans adhesion was evaluated on the retrieved archwires using real-time polymerase chain reaction (PCR). Enamel mineral content in the arches related to the uncoated and coated archwires was evaluated using DIAGNOdent. RESULTS: After 1 month of intraoral use, both coated and uncoated archwires exhibited a rougher surface with coated archwires demonstrating greater quantum of increase (control, P = 0.002; experimental, P = 0.002). S mutans adhesion was more in uncoated archwires (P = 0.0005). The TiO2 nanoparticle coating on the NiTi archwires showed delamination, deterioration and was lost by 60% at the end of 1 month. Laser fluorescence values did not show any significant difference (control, P = 0.182; experimental, P = 0.105). CONCLUSIONS: TiO2 nanoparticle coating on NiTi archwires causes an initial reduction in roughness; however, at the end of 1 month, the benefit was lost. S mutans adhesion was lesser on the coated wires, which could be attributed to reduced initial Ra and antibacterial property of TiO2. Orthodontic archwire appears to have a limited role in enamel demineralization.

Role of polymorphisms of MSX1 and PAX9 genes in palatal impaction of maxillary canines.

OBJECTIVE: Maxillary canines are the second-most commonly impacted teeth. About two-thirds of the impacted maxillary canines are palatally impacted. Studies in the past have shown that 40% of cases with palatal impaction of maxillary canines presented with agenesis of third molars. Sporadic agenesis of third molars have been associated with polymorphisms in the MSX1 and PAX9 genes. The present study aims at evaluating the association between polymorphisms of PAX9, MSX1 and palatally impacted canines in a random population sample. DESIGN AND SETTING: Fifty individuals with palatally impacted maxillary canines and 50 gender and age-matched controls were included in this study. METHODS: Single nucleotide polymorphisms (SNPs), rs12532 of MSX1 and rs2073247 of PAX9, were genotyped using polymerase chain reaction and restriction fragment length polymorphism. The significance of the differences among the groups was assessed by odds ratio and Chi-squared test with a 95% confidence interval. RESULTS: Single nucleotide polymorphisms rs12532 [MSX1] and rs 2073247 [PAX9] showed a statistically significant association with palatal impaction of maxillary canines. In addition, the combined presence of the AG/CT genotypes of these genes in an individual caused a significant increase in the risk for palatal impaction. CONCLUSION: These results suggest that the rs12532 and rs2073247 polymorphisms of genes MSX1 and PAX9 are positively associated with palatal impaction of maxillary canines. Future studies investigating various other SNPs of these genes in a larger sample of different populations could provide clinching details.

Comparative evaluation of salivary bisphenol A levels in patients wearing vacuum-formed and Hawley retainers: An in-vivo study.

INTRODUCTION: The aims of the study were to evaluate and compare the bisphenol A (BPA) levels in saliva in patients using vacuum-formed retainers or Hawley retainers. METHODS: Forty-five patients who had completed their fixed orthodontic treatment and were entering the retention phase were randomly allocated into 1 of 3 groups: vacuum-formed retainer, Hawley retainer fabricated by heat cure, and Hawley retainer fabricated by chemical cure. Saliva samples were collected immediately before placement, within 1 hour after placement, 1 week and 1 month after placement. Statistical analyses were performed by using 2-way analysis of variance and post-hoc multiple-comparisons Tukey HSD tests. RESULTS: Statistically significant BPA levels in saliva were found for all groups (P ≤0.05). The highest levels were noted in the vacuum-formed retainer group, followed by Hawley retainers fabricated by chemical cure; the lowest levels were found with Hawley retainers fabricated by heat cure. CONCLUSIONS: With many options available for removable retainers, clinicians should consider the BPA release from these retainers; a Hawley retainer fabricated by heat cure is a favorable choice.

Assessment of antibacterial and cytotoxic effects of orthodontic stainless steel brackets coated with different phases of titanium oxide: An in-vitro study.

INTRODUCTION: Our objective was to assess the antibacterial and cytotoxic effects of orthodontic stainless steel brackets coated with different phases of photocatalytic titanium oxide. METHODS: From a total sample of 115 brackets, 68 orthodontic stainless steel brackets were coated with titanium oxide using a radiofrequency magnetron sputtering machine. The coated brackets were then converted into 34 each of the anatase and rutile phases of titanium oxide. These brackets were subdivided into 4 groups for antibacterial study and 3 groups for cytotoxicity study. Brackets for the antibacterial study were assessed against the Streptococcus mutans species using microbiologic tests. Three groups for the cytotoxicity study were assessed using the thiazolyl tetrazolium bromide assay. RESULTS: The antibacterial study showed that both phases were effective, but the rutile phase of photocatalytic titanium oxide had a greater bactericidal effect than did the anatase phase. The cytotoxicity study showed that the rutile phase had a greater decrease in viability of cells compared with the anatase phase. CONCLUSIONS: It is recommended that orthodontic brackets be coated with the anatase phase of titanium oxide since they exhibited a significant antibacterial property and were only slightly cytotoxic.

A comparative evaluation of ion release from different commercially-available orthodontic mini-implants - an in-vitro study.

BACKGROUND: Titanium alloy mini-implants have become popular in recent times and have been extensively used and studied. Although corrosion resistance of orthodontic materials has always been of concern, this property has been the least explored. The present study aimed to assess the composition, surface characterisation and corrosion resistance of five commercially available mini-implants by assaying ion release in artificial saliva. METHODS: Ten mini-implants each from five companies were obtained: Group 1 - AbsoAnchor (Dentos Inc, South Korea); Group 2 - Microimplant Anchorage System (MIA, Biomaterials Korea); Group 3 - The Orthodontic Mini Anchorage System (TOMAS, Dentaurum, Germany); Group 4 - mini-implants (Denticon, Maharashtra, India); Group 5 - orthodontic mini-implants (lJ.Orthodontics, Kerala, India). One mini-implant from each group was subjected to characterisation and surface microstructure analysis using Energy Dispersive Atomic Spectrometry (EDAX) and Scanning Electron Microscope (SEM), respectively. Ten mini- implants were immersed for 30 days in Fusayama-Meyer artificial saliva solution and the release of titanium, aluminium and vanadium ions was detected with Inductively Coupled Plasma - Optical Emission Spectrometry (ICP-OES). The Kruskal-Wallis test was used for multi-variate analysis. In order to determine the significant differences between the groups on independent samples, the Mann-Whitney U test (bi-variate analysis) was applied. RESULTS AND CONCLUSION: All groups showed machining defects but surface pitting after immersion was mostly evident in Group 4. Although the composition of all the implants was comparable, there was a statistically significant difference in the Ti, Al and V release between Group 4 - the group with maximum release - and Group 2, the group with least release.

Assessment of maximal inspiratory and expiratory pressures in skeletal Class II patients with different growth patterns.

OBJECTIVES: To evaluate maximal inspiratory (MIP) and expiratory (MEP) pressures, which are reflective of respiratory muscle strength, in skeletal Class II patients with different growth patterns (horizontal, average, and vertical) and to correlate those with airway dimension. MATERIALS AND METHODS: Patients with a Class II skeletal base seeking orthodontic treatment were assigned to the following groups: average, horizontal, and vertical growth pattern. The control group (n = 14) comprised patients with a Class I skeletal base and average growth pattern. Airway dimensions were obtained using cone-beam computed tomography scans, and a spirometer with a pressure transducer was used for assessment of MIP and MEP. Routine spirometry for assessment of lung function was also performed. RESULTS: No significant differences were found in maximal inspiratory and expiratory pressures for the study groups in comparison with the control group. Class I patients had significantly greater oropharyngeal and nasopharyngeal airway volumes compared with the study groups. No significant difference in minimal cross-section area of the airway was observed among groups. A weak positive correlation between maximal inspiratory pressure and airway volume was observed. CONCLUSIONS: Although Class I patients displayed significantly greater oropharyngeal and nasopharyngeal airway volumes, there was no significant difference in respiratory muscle strength or airway function between Class II patients with different growth patterns and the Class I control group. The findings underscore the significance of exploring factors beyond craniofacial growth patterns that may contribute to sleep-related breathing disorders.

Systemic consumption of probiotic curd and use of probiotic toothpaste to reduce Streptococcus mutans in plaque around orthodontic brackets.

INTRODUCTION: The objectives of the study were to evaluate and compare the effects of the systemic consumption of probiotic curd and the topical application of probiotic toothpaste on the Streptococcus mutans levels in the plaque of orthodontic patients. METHODS: The study consisted of 60 orthodontic patients divided into 3 groups of 20 each. Group 1 was the control group. The patients in group 2 were given probiotic curd, and those in group 3 were asked to brush twice daily with probiotic toothpaste (GD toothpaste; Dental Asia Manufacturing, Shah Alam, Selangor, Malaysia). Samples were collected at 2 times: before the study began and after 30 days. Plaque specimens were collected from the labial surfaces immediately surrounding the orthodontic brackets of the maxillary lateral incisors using a 4-pass technique. The presence of S mutans was evaluated using real-time polymerase chain reaction. Statistical analysis was performed, and comparisons were made using a 2-tailed chi-square test for categorical data (P <0.05). RESULTS: At the end of the study, there were reductions in S mutans concentration in groups 2 and 3 that were statistically significant compared with group 1, but there was no statistically significant difference between groups 2 and 3. CONCLUSIONS: The consumption of probiotic curd and the use of probiotic toothpaste cause a significant decrease in the S mutans levels in the plaque around brackets in orthodontic patients. Although the probiotic toothpaste was more effective than systemic consumption, this was not statistically significant.

The Evaluation of Maxillary Sinus Dimensions in Different Craniofacial Patterns: A Systematic Review and Meta-Analysis.

This systematic review was intended to evaluate the maxillary sinus dimensions in vertical and sagittal craniofacial patterns and to assess if there was a difference among the craniofacial patterns. A systematic search was performed in seven databases till February 2021. The risk of bias was performed with modified Newcastle Ottawa scale. Meta-analysis was performed using random effects model. Twelve studies were included in the review and 8 in the meta-analysis. Compared to Class I malocclusion, the maxillary sinus area is greater in Class II and lesser in Class III malocclusion. On comparing normo-divergent growth pattern, the maxillary sinus area is lesser in hypo-divergent and greater in hyper-divergent individuals. Most of the studies were graded as satisfactory. The measurements are greater in hyper-divergent Class II malocclusion and in males.

Effects of varying attachment positions on palatal displacement of maxillary incisors with clear aligner therapy : A three-dimensional finite element analysis.

BACKGROUND: Clear aligner therapy (CAT) has evolved as an esthetic alternative to fixed appliance therapy. However, studies on the effects of attachments on CAT are scarce. This research was done to evaluate the effect of labial and/or palatal attachments on maxillary incisor displacement in CAT through finite element analysis (FEA). MATERIALS AND METHODS: Finite element modeling was used to create four models with aligners. The following combinations were created: (1) without attachments (WO), (2) with labial attachments (WLA), (3) with palatal attachments (WPA), (4) with labial and palatal attachments (WLPA). Maximum displacement, directional displacement and stresses induced following a palatal displacement of 0.25 mm was evaluated for each of the four models. RESULTS: Models without attachments and those with palatal attachments showed a greater tooth movement at the incisal part of the crown (0.22 mm and 0.24 mm, respectively) than the models with labial and labiopalatal attachments (0.21 mm and 0.19 mm, respectively). The von Mises stresses were concentrated at the middle third of the roots in the model with the labial attachments (30.257 MPa), while in the other three models, stresses were concentrated at the cervical third of the roots. CONCLUSIONS: Maximum displacement was seen at the incisal third of the maxillary incisors in the model with palatal attachments. The model without attachment generated the highest stresses. However, labial attachments as compared to other models appear to offer some biomechanical advantage by reducing uncontrolled tipping.

Posttreatment Stability Following Facemask Therapy in Patients with Skeletal Class III Malocclusion: A Systematic Review.

Background: Skeletal class III malocclusion is a challenging condition that orthodontists frequently come across. The facemask (FM) is a device commonly used to treat this malocclusion. However, the stability of this orthopedic correction remains unclear, and collective documentation of the short-, mid-, and long-term stability after FM therapy is necessary. Aim: The aim of the systematic review was to assess posttreatment stability following FM therapy in patients with skeletal class III malocclusion. Materials and methods: Through a predefined search strategy, electronic searching was conducted in PubMed, Latin American and Caribbean Health Sciences Literature (LILACS), Cochrane, Ovid, Embase, Scopus, and Web of Science until 30th June 2022. Eligible study selection, data extraction, and evaluation of the risk of bias were performed independently by two review authors according to the Cochrane tool for assessing the risk of bias in randomized trials (RoB 2.0 tool) and the Risk of Bias in Nonrandomized Studies-of Interventions (ROBINS-I) tool for nonrandomized trials. A total of 14 studies were finally considered eligible. The systematic review revealed that the maxillo-mandibular differential reverted to class III. The maxillary changes achieved were variable, with SNA angles ranging between -0.7° and 1.9°. Changes in the mandible were greater with an increase in the SNB angle ranging between 0.33° and 3.62°. The lower anterior facial height increased. The maxillary and mandibular incisors were proclined, and the overjet and overbite decreased. The soft tissue changes were insignificant. Conclusion: The effects of FM therapy were found to be stable in the short-term follow-up period. The long-term follow-up revealed that the effects of FM therapy remained stable for the maxilla. However, the mandible continued to grow in a horizontal and unfavorable direction until the adolescent growth spurt. Clinical significance: The major variable that determines the long-term success of FM therapy is the amount and direction of mandibular growth during the adolescent growth spurt. More focus on restricting unfavorable mandibular growth and duration of retention is needed for post-FM therapy. Others: PROSPERO (CRD42021218960). How to cite this article: Raghupathy Y, Ananthanarayanan V, Kailasam V, et al. Posttreatment Stability Following Facemask Therapy in Patients with Skeletal Class III Malocclusion: A Systematic Review. Int J Clin Pediatr Dent 2023;16(6):897-907.

The effect of nitrogen-doped titanium dioxide-modified stainless steel brackets on Streptococcus mutans.

OBJECTIVES: To evaluate the effect of nitrogen (N)-doped titanium dioxide (TiO2) coated stainless steel brackets activated with natural visible light and dental operating lights on Streptococcus mutans concentration in the plaque of orthodontic patients at 30 and 60 days. MATERIALS AND METHODS: A total of 30 patients were recruited for this split-mouth study; 60 upper lateral incisor brackets constituted the study sample. A total of 30 brackets (15 right and 15 left) were coated with N-doped TiO2 using the (radio frequency) magnetron sputtering method. Plaque samples were collected at 30 days and 60 days after appliance placement. S mutans concentration was evaluated using real-time polymerase chain reaction. RESULTS: At both time intervals, the concentration of S mutans in the control group was greater than that in the study group (P = .005). In both the study and the control groups, the S mutans concentrations significantly increased from 30 to 60 days (P = .005). CONCLUSIONS: N-doped TiO2, on exposure to natural visible light and dental operating light, was effective in reducing the plaque concentration of S mutans in orthodontic patients. The efficacy was better at 30 days than at 60 days after placing the orthodontic appliances.

Comparative Evaluation of Soft Tissue Profile Changes with Herbst and Twin Block Appliances in Class II Malocclusion Patients: A Perception Study.

OBJECTIVE: To comparatively evaluate the perception of patients' soft tissue profiles treated with Herbst and Twin Block appliances and correlate the perception with cephalometric parameters. METHODS: The record of 30 patients (15 Herbst and 15 Twin Block) treated for a period of 6 months (±1.1 months) was included in the study. A total of 60 resulting profile silhouettes (from pre- and post-functional profile photographs) were evaluated by 30 examiners and were divided into 3 groups: orthodontists, general dentists, and laypersons. The profiles were arranged in a randomized order, and the examiners rated the profiles using a visual analog scale. Paired t-test and independent t-test were performed to find a significant difference within and between the appliances, respectively. A treatment outcome correlation was done using Pearson's correlation test between the visual analog scale scores and cephalometric parameters. RESULTS: Within the appliances, the orthodontist perceived a difference with only the Twin Block appliance (P = .02). The general dentists perceived a significant difference with both Herbst (P = .02) and Twin Block (P = .001) appliances, whereas the laypersons did not perceive any profile improvement on treatment with functional appliances. However, between the appliances, no statistically significant profile difference was seen with all 3 groups of examiners. The ANB angle had a significant negative correlation (P = .007) to the visual analog scale scores given by the orthodontists for the Herbst appliance. CONCLUSION: No perceptible difference was found in the profile enhancement between Herbst and Twin Block appliances with all 3 groups of examiners. The ANB angle contributed to the difference in profile perception between the appliances for the orthodontists.

Evaluation of the genotoxic effects of fixed appliances on oral mucosal cells and the relationship to nickel and chromium concentrations: an in-vivo study.

INTRODUCTION: The release of metal ions from fixed orthodontic appliances is a source of concern. The aim of this study was to evaluate genotoxic damage in the oral mucosal cells of patients wearing fixed appliance, and the nickel and chromium ion contents in these cells. METHODS: Twenty patients undergoing orthodontic treatment formed the experimental group, and 20 untreated subjects comprised the control group. Oral mucosal smears were collected at 2 times: at debonding and 30 days after debonding. The smears were stained with Papanicolaou stain and studied under a light microscope to evaluate the presence of micronuclei. Inductively coupled plasma-mass spectrometry was used to quantify the presence of metal ions. The data were subjected to the Mann-Whitney U test and the Spearman rank correlation test. RESULTS: The mean micronuclei frequency was significantly higher in the treated group than in the control group at debonding; the difference was smaller and not statistically significant 30 days after debonding. The nickel and chromium ion contents in the experimental group were not significantly higher than in the control group. No correlation could be established between micronuclei frequency and metal ion content. CONCLUSIONS: Nickel and chromium alloys of orthodontic appliances emit metal ions in sufficient quantities to induce localized genotoxic effects, but these changes revert on removal of the appliances.