RESUMEN

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.

Asunto(s)

RESUMEN

OBJECTIVES: To assess and evaluate the collum angle (CA) of the anterior teeth of the permanent dentition. METHODS: A search in seven databases for articles that had measured the CA in sagittal malocclusions was conducted until November 30, 2021. The risk of bias was assessed using the Modified Newcastle Ottawa scale. CA measurements using Cone Beam Computed Tomography or lateral cephalograms were included. The CA data were summarized by random-effects inverse generic meta-analyses. RESULTS: Qualitative analysis of the 17 selected articles revealed that four were rated as "very good," 12 as "good" and 1 as "satisfactory." CA was 4.7° (95% CI of 3.1 to 6.4) and 2.0° (95% CI of 0.1 to 3.9) greater in Class II division 2 and Class III malocclusions respectively, than in Class I malocclusion cases. CONCLUSION: Majority of the studies were rated as good or very good. Most studies evaluated the CA of the maxillary central incisors in Class II division 2 malocclusion. Studies assessing other maxillary anterior and mandibular anterior teeth are required. CLINICAL SIGNIFICANCE: Practice of esthetic dentistry for teeth with increased CA is of clinical importance since the angle would determine the longevity and esthetic/cosmetic success of the rehabilitation. Placement of dental implants in areas of missing teeth with increased collum angle leads to excessive stress between the fixture and abutment leading to gingival recession. Thus, knowledge about the collum angle of anterior teeth and its variations in sagittal malocclusions would enable precise treatment planning in the field of esthetic dentistry.

Asunto(s)

RESUMEN

INTRODUCTION: Fixed appliances limit patients' ability to clean their teeth, thus making orthodontic patients highly susceptible to developing white spot lesions (WSLs). Using patient compliance would be one of the simplest methods to prevent WSLs. METHODS: A parallel trial design with 34 patients that met the eligibility criteria were randomized to experimental (received Blue M oxygen for health toothpaste) and control (received Colgate Total fluoridated toothpaste) groups. The eligibility criteria were that the patients should be aged 13-30 years, on fixed mechanotherapy, had undergone therapeutic extraction of all first premolars, had completed leveling and aligning, and had satisfactory oral hygiene (assessed using pretreatment and current Simplified Oral Hygiene Index scores). The objectives were to assess the effects of active oxygen-containing toothpaste on Streptococcus mutans (SM) and WSLs in patients undergoing fixed mechanotherapy. The random allocation sequence was generated using the RAND function in Microsoft Excel. The sequence generated was sealed in opaque white envelopes. The investigators and the participants were blinded until allocation. Blinding of the first author (J.A.G.) who dispensed the toothpaste or the participants was not possible. The outcome assessment was blinded by coding the plaque specimens sent for real-time polymerase chain reaction (RT-PCR) to ensure that the final data assessment was blinded. The study setting was the Department of Orthodontics and Dentofacial Orthopedics, Sri Ramachandra Institute of Higher Education and Research (SRIHER) University. The primary outcome was SM counts, which were analyzed using RT-PCR. The secondary outcome was WSL assessment, performed using DIAGNOdent and International Caries Detection and Assessment System (ICDAS) II criteria at baseline and after 4 weeks. The data were subjected to statistical analysis. RESULTS: Thirty-four patients were randomized to 17 per group and analyzed. RT-PCR showed lower SM in the experimental group (Ct = 32.25 ± 10.6) than in the control group (Ct = 30.9 ± 10.49). However, this was not statistically significant (P = 0.70). ICDAS scores remained the same from baseline and after 4 weeks for both groups. The DIAGNOdent values were in tandem with the ICDAS scores and showed minimal change for the 2 groups (P >0.05). A strong positive correlation was observed for DIAGNOdent and ICDAS scores (τb >0.30). No harms or adverse effects were observed or reported by the patients during the experimental period. CONCLUSIONS: The active oxygen-containing toothpaste showed a greater inhibitory effect on SM than the fluoridated toothpaste. However, this effect was minimal. Both kinds of toothpaste showed negligible effects on WSLs. Thus, active oxygen-containing toothpaste is as effective as fluoridated toothpaste. REGISTRATION: The Trial was registered in the Controlled Trials Registry India (CTRI/2021/10/037458). PROTOCOL: The full protocol can be obtained from any of the authors via e-mail. FUNDING: The project was self-funded.

Asunto(s)

RESUMEN

BACKGROUND/OBJECTIVE: Early diagnosis and the interception of potential impaction is the most desirable approach for management of impacted canines. Several radiographic predictors have been previously proposed to predict canine impaction. Hence the aim of this systematic review was to identify the most effective radiographic predictors of maxillary canine impaction. SEARCH METHOD: The following databases were searched: PubMed via Medline, Science Direct, LILACS, Cochrane library and Ovid MEDLINE. All comparative studies including observational and interventional studies that compare a canine impacted group versus a control group were included. The primary outcome assessed were the radiographic predictors used for diagnosis of maxillary canine impaction. RESULTS: Thirteen articles were included in this systematic review. The most commonly used parameters are sector classification, angle formed by the long axis of the canine and the midline, angle formed by the long axis of the canine and the lateral incisor, angle formed by the long axis of the canine and the occlusal plane, and perpendicular distance between the canine cusp tip to the occlusal plane and to the midline. Meta-analysis indicated that the angle formed by the long axis of the canine and the midline with a value of 19.9° and above (95% CI of 6.68 to 33.15), the angle formed by the long axis of the canine and the lateral incisor with a value of 20.01° and above (95% CI of 7.52 to 32.51) favoured canine impaction. CONCLUSIONS: With eleven of the thirteen articles showing a low risk of bias/good quality, it can be concluded that canine impactions can be predicted using various linear and angular parameters measured on different radiographs (orthopantomograms, lateral cephalograms, postero-anterior cephalograms and cone-beam computed tomography). However, further three-dimensional studies are required to accurately predict and diagnose canine impactions. REGISTRATION: The study protocol was registered on the International Prospective Register of Systematic Reviews (Reg no: CRD42020200518).

Asunto(s)

RESUMEN

Introduction: The complications of soft drink consumption during orthodontic treatment includes degradation of enamel, reduction in the shear bond strength of orthodontic brackets, and also corrosion of orthodontic wires. The main objective of this review is to discuss the adverse effects of carbonated soft drink (CSD) consumption on patients undergoing fixed orthodontic treatment. Methods: A search of studies in MEDLINE (via PubMed), the Cochrane library, Web of science, IndMED, EMBASE, Google scholar and limited grey literature on the effects of consumption of CSDs was conducted. All pertinent abstracts were reviewed for inclusion. Full articles were retrieved for abstracts or titles that met the initial inclusion criteria or lacked sufficient detail for immediate exclusion. Results: Out of the 4484 results obtained from search, 16 articles were selected based on title and 6 articles were eliminated after reading the abstracts. 10 articles were selected for systematic review which included 6 invitro studies, 1 animal study, 1 observational study and 2 invivo studies. Of these, six studies evaluated the effects of carbonated drinks on the shear bond strength of brackets on enamel of which two evaluated the microhardness of enamel, two studies evaluated the mechanical and chemical properties of wires, one evaluated tooth movement and one study focussed on white spot lesions. The results from the selected articles showed that with the consumption of carbonated drinks, there was reduced shear bond strength of orthodontic brackets, altered enamel characteristics, alteration of mechanical and physical properties of orthodontic wires and decrease in rate of orthodontic tooth movement. Conclusion: Based on the available evidence, CSD consumption during orthodontic treatment definitely has an effect on orthodontic appliances, enamel and possibly on tooth movement.

Asunto(s)

RESUMEN

INTRODUCTION: The collum angle that defines the crown root angulation of the single rooted teeth plays an important in treatment planning. OBJECTIVE: To compare the collum angle (crown root angulation) of maxillary and mandibular anterior teeth in different skeletal malocclusions using Cone Beam Computed Tomography (CBCT). MATERIALS AND METHODS: Sixty subjects were categorized into four groups (fifteen subjects in each group) Class I, Class II division 1, Class II division 2 malocclusion and Class III based on Angle classification, Wits and ANB. The collum angle of maxillary and mandibular anterior teeth was measured using CBCT. One way ANOVA, Post hoc comparison with Tukey HSD and Paired t-test were used to analyse the measured data. RESULTS: The collum angle of corresponding right and left side teeth were averaged. Thus, the mean and standard deviation of the collum angle (n-30) were generated for maxillary and mandibular central incisors, lateral incisors, and canines. A statistically significant increase was observed in the maxillary central incisors of Class II division 2 and mandibular lateral incisors of class III malocclusion. The collum angle was increased in mandibular canines of Class III malocclusion when compared with class I and Class II division 2 malocclusion. The collum angle was negative in mandibular central incisors of Class II division 2. No statistically significant difference was observed in the mean collum angle between the right and left side anterior teeth in all the four groups. CONCLUSION: A variation in Collum angle was observed between the maxillary and mandibular anterior teeth and malocclusions. The effect of these variations in collum angle in torque expression and biomechanics should be kept in mind by the orthodontist before treatment planning especially in Class II division 2 malocclusion.

Asunto(s)

RESUMEN

OBJECTIVES: Leptin, a polypeptide which is related to body fat regulation, is also found to have a role in the inflammatory reaction. The aim of this study is to assess the concentration of leptin in Gingival Crevicular Fluid (GCF) during orthodontic force application and to correlate its concentration to rate of tooth movement. METHODS: Twenty orthodontic patients (10 males and 10 females) were selected for the study. Leptin concentration was measured at T0, before force application; T1, one hour after force application; T2, one day after force application; T3, one week after force application; T4, one month after force application. GCF was collected using filter paper strips from the distal aspect of gingival sulcus of the right maxillary canine distalized by an active lace-backs of tooth movement was measured on dental casts, before and one month after force application. One-way ANOVA with Bonferroni correction and Pearson's correlation test were used to analyze the data. RESULTS: The mean GCF leptin concentration increased from T0 to T1, rose to a peak at T2, then declined to a minimum value at T3 and then increased to a value at T4, closer to the base line value (T0), and it was statistically significant (P < 0.05). There was positive correlation of the overall mean leptin concentration to rate of tooth movement (correlation coefficient = 0.634). CONCLUSION: There was a biphasic change in GCF leptin concentration during one cycle of orthodontic force application. There was a positive correlation between the GCF leptin concentration and rate of tooth movement.

RESUMEN

OBJECTIVES: The aim of this study was to assess and compare the cervical vertebral maturation stages in adults with different skeletal bases. MATERIALS AND METHODS: A total of 133 lateral cephalograms were selected and allotted in to three groups A (50), B (43) and C (40) having Class I, Class II and Class III skeletal base respectively. Cervical vertebral maturation (CVM) using was assessed using Hassel and Farman method. The morphology of the vertebrae was evaluated by calculating the amount of concavities in the inferior borders of C2, C3 and C4 and the base to anterior height ratio (BAR) and posterior to anterior height ratio (PAR) for C3 and C4. RESULTS: The overall distribution of CVMI 6 was the least followed by stages 5 and 4. The amount of concavities in C2, 3 and 4 were statistically significant (P<0.05) and was highest in Group C. The distribution of C3 and C4 BAR<0.96 was the least. The distribution of CVM 4 and C4 BAR>1.045 was greater in Group B compared to other groups. CONCLUSION: Increased prevalence of lower levels of cervical vertebral maturation was observed in adult lateral cephalograms and in Class II skeletal base in particular.

Asunto(s)

RESUMEN

OBJECTIVES: To assess and compare the concentration of leptin in saliva between normal weight and overweight individuals and to evaluate the rate of orthodontic tooth movement. MATERIALS AND METHODS: Thirty female subjects were divided into two groups: I (normal weight) and II (overweight group) based on their body mass index. All subjects underwent fixed appliance therapy requiring upper first premolar extraction and distal movement of the canine. Distal force was applied to the maxillary right canine using active lacebacks. Salivary samples were collected just before force application (T0), 1 hour (T1), and 1 month (T2) after force application. The rate of tooth movement was evaluated over 3 months and was measured on study models. RESULTS: At all three time intervals, mean leptin concentration was greater in overweight individuals than normal weight individuals. In both groups at T1, the mean leptin concentration was found to increase significantly compared with the baseline value (T0), but at T2, the leptin concentration declined to values lesser than the baseline values (T0). CONCLUSIONS: Overweight individuals had greater salivary leptin concentration. There was a positive correlation between salivary leptin concentration and rate of tooth movement in both normal and overweight individuals. The rate of tooth movement is decreased in overweight individuals as compared with normal weight individuals.

Asunto(s)

Asunto(s)

Asunto(s)

RESUMEN

BACKGROUND: The role of ankyloglossia in etiology of malocclusion is not much discussed over the years. The aim of the present study was to assess the skeletal and dental characteristics in subjects with ankyloglossia. METHODS: Fifty-seven subjects diagnosed with ankyloglossia (group 1) were compared with 60 subjects (group 2) without ankyloglossia, who had class I skeletal base. Ankyloglossia was diagnosed and graded (mild, moderate, severe and very severe) using Kortlow's method. SNA, SNB, ANB, Go-Gn-SN angle, FMA, maxillary and mandibular intercanine widths and intermolar widths, tooth size-arch length discrepancy in maxillary and mandibular arches and overbite were measured. Independent t test was used to compare the mean parameters between the two groups. Analysis of variance and Tukey honestly significant difference were used to compare mean parameters among various grades of ankyloglossia. RESULTS: Majority of group 1 subjects belonged to class I skeletal base followed by class II and class III skeletal bases. Moderate ankyloglossia was most common in group 1. The mean maxillary and mandibular intercanine widths and maxillary intermolar width were statistically significant in independent t test (P<0.01) and reduced in group 1. In ANOVA followed by Tukey HS, the Go-Gn-SN angle and overbite were statistically significant among different grades of ankyloglossia (P<0.05). CONCLUSIONS: Subjects with ankyloglossia had reduced maxillary and mandibular intercanine widths and reduced maxillary intermolar width. The mandibular plane angle and overbite were altered with severity of ankyloglossia.

Asunto(s)

RESUMEN

AIM: The present study aimed to measure the magnitude of the collum angle (crown-root angulation) of maxillary central incisors present in Class II, division 2 malocclusion and to relate the changes in its magnitude with variations in the lower lip line. METHODS: A set of 120 conventional lateral cephalograms were selected and divided into three groups of 40 each based on the type of malocclusion presented: Class II, division 2 (group 1); Class II, division 1 (group 2); and Class I (group 3). The collum angle of the maxillary central incisor was measured, and the lower lip line was recorded. RESULTS: Analysis of variance (ANOVA) revealed that the mean collum angle was statistically significantly different in the three groups. The mean collum angle was greatest in Class II, division 2 malocclusion (group 1). The mean collum angles were 3.24 ± 4.69 degrees, 0.95 ± 1.06 degrees, and 1.05 ± 1.50 degrees in groups 1, 2, and 3 respectively. In χ ² test comparison of the location of the lower lip line (incisal, middle, or apical third of the central incisor) among the three groups, the lower lip line was found to contact the middle third of the central incisor most frequently in Class II, division 2 malocclusion. ANOVA followed by Tukey honestly significant difference (HSD) test showed that the mean collum angle is significantly increased when the lower lip is in the middle third (P < .05) of the central incisor. CONCLUSION: Variations in magnitude of the collum angle with the change in the lower lip line suggest a probable etiologic role of the lower lip line in the development of the collum angle.

Asunto(s)

RESUMEN

The aim of this cross-sectional study was to evaluate serum levels of the hormone, dehydroepiandrosterone sulphate (DHEAS), during the pre-pubertal, pubertal, and adult stages of skeletal maturation based on the methods of Björk and Grave and Brown of assessing hand-wrist radiographs. The levels of the DHEAS of each individual were measured using quantitative enzyme-linked immunosorbent assay and correlated with the corresponding stages in their hand-wrist radiograph. This study was performed on 60 subjects (30 females and 30 males) aged from 7 to 30 years. Analysis of variance followed by a Tukey honestly significant difference test showed that the serum levels of the DHEAS were statistically significant at (P < 0.01) in all three groups. The serum levels were significant (P < 0.05) when each of the three groups were individually compared with the other two groups. The mean DHEAS levels were 0.43 ± 0.28, 2.17 ± 0.92, and 4.60 ± 1.34 µg/ml in the pre-pubertal, pubertal, and adult groups, respectively. There was a gradual increase in the hormonal level with progressing skeletal age. The adult group showed the highest DHEAS level and the pre-pubertal group the lowest. Serum levels of DHEAS showed a constant increase from pre-puberty to adulthood, and at the same level of skeletal maturation, both females and males had similar hormone levels. This finding highlights the fact that the hormone DHEAS plays a significant role and can be a valuable tool in assessing skeletal maturation.

Asunto(s)