The Hyrax appliance with tooth anchorage variations in surgically assisted rapid maxillary expansion: a finite element analysis.

PURPOSE: It is known that a correct transverse maxillary dimension is a key factor for a stable occlusion, which brings functional and esthetic benefits for the patient. In patients presenting maxillary atresia and the completion of bone growth, a highly recommended option for correction is the surgically assisted rapid maxillary expansion (SARME) associated with the Hyrax appliance. The objective of this study was to evaluate the influence of tooth anchorage variations of the Hyrax appliance in SARME through finite element analysis, evaluating which anchorage option might be associated with more effective orthopedic results with less undesired side effects. METHODS: Five different dental anchoring conditions for the Hyrax appliance were simulated through FE analysis applying premolars and molars as anchorage, having the same force applied by the activation of the Hyrax screw (0.5 mm) in all groups. The maxillary displacement results (axes X, Y, and Z) and generated stresses for both teeth and maxillary bone were calculated and represented using a color scale. RESULTS: All groups presented significant bone displacement and stress concentration on anchoring teeth, with the group presenting anchorage in the 1st and 2nd molars showing the greatest maxillary horizontal displacement (axis X) and suggesting the lowest tendency of dental vestibular inclination. CONCLUSIONS: Variations in dental anchorage might substantially affect the maxillary bone and teeth displacement outcome. The protocol for the Hyrax apparatus in SARME applying the 1st and 2nd molars as anchorage might generate less tilting and inclination of the anchoring teeth.

Evaluation of Electromyographic Activity of Masticatory Muscles in Adults with Posterior Crossbite.

Introduction: There is evidence that patients with posterior crossbite (PXB) have neuromuscular changes in the masticatory muscles. However, up to the present time, the relationship among these changes on the electromyographic activity of the masticatory muscles is still unclear. Objective: To systematic review the available literature on the electromyographic activity of masticatory muscles in adults with PXB. Methods: Between August 22 and September 9, 2020, we searched the following seven electronic databases: PubMed, EMBASE, Web of Science, Cochrane Library, SciELO, LILACS, and Scopus. No restrictions were applied regarding the language and year of publication. This systematic review was registered in the Prospective Register of Systematic Reviews (PROSPERO - CRD42020205057) database and conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. After data selection and extraction, the methodological quality of the selected studies was conducted independently by two reviewers, using two different evaluation tools. Results: 6957 records were initially located after the search process. In the end, eight papers were selected. Most studies were classified as having average to low methodological quality and moderate to high risk of bias. Based on the available evidence, adult patients with PXB have electromyographic activity changes in the masticatory muscles when compared with individuals without PXB. Moreover, adult patients with unilateral posterior crossbite (UPXB) have asymmetrical electromyographic activity when the crossbite side is compared with the noncrossbite side. Conclusion: Despite the lack of studies with high methodological quality, electromyographic evaluation of masticatory muscles should be considered in the diagnosis and in the orthodontic treatment plan of patients with PXB. Prospective studies with a higher sample size and follow-up time, conducted using a rigorous scientific methodology, are necessary to reach a more reliable conclusion.

Oral health-related quality of life in women with temporomandibular joint disk anterior displacement before and after disk repositioning and anchoring surgery assessed with the Oral Health Impact Profile (OHIP-14).

OBJECTIVES: The aim of this study was to assess and compare oral health-related quality of life (OHRQOL) in women with temporomandibular joint (TMJ) disk displacement without reduction, before disk repositioning and anchoring surgery, in short-term follow-up, in different age groups, and with use of the Oral Health Impact Profile (OHIP-14). STUDY DESIGN: Fifty women ages between 17 and 60 years were divided into 4 age groups: 17-27, 28-38, 39-49, and 50-60 years. All the patients were asked to answer the OHIP-14 form before surgery and during their short-term follow-up. Seven domains of OHRQOL were rated on a 5-point Likert scale from 0 (never) to 4 (very often). Domains' scores and total OHIP-14 were compared between times by using Student's t test in the whole sample and in the 4 age groups. RESULTS: Both the whole sample and the age groups (17-27, 28-38, 39-49 years) showed a statistically significant decrease in all scores (P < .01). The age group 50-60 years showed a decrease in scores significant only in functional limitation (P = .05) CONCLUSIONS: TMJ disk anterior displacement had a negative impact on women's OHRQOL because of physical pain, physical disability, and psychological discomfort. TMJ disk repositioning and anchoring surgery improved overall OHRQOL in patients between 17 and 49 years of age; however, in patients between 50 and 60 years of age, there was improvement only in physical pain.

Temperature Rises in the Pulp Chamber with Different Techniques of Orthodontic Adhesive Removal.

INTRODUCTION: The aim of this in vitro study was to compare the temperature rises in the pulp chamber and time spent with different techniques for orthodontic resin adhesive removal. METHODS AND MATERIALS: Adhesive removal was performed in 20 extracted human maxillary second premolars with five techniques: high-speed tungsten carbide burs with water-cooling (BurH-cool) and without cooling (BurH), low-speed carbide burs (BurL), low-speed aluminum-oxide discs (DiscL), and low-speed fiberglass burs (BurFGL). Pulp chamber temperature was measured with a thermocouple probe and time spent was recorded with a digital stopwatch. Comparisons of temperature rise and time between the techniques were performed with Analysis of variance and Tukey's Honestly test. Correlation between variables was investigated with Pearson's correlation coefficient. RESULTS: Temperature rise and time were statistically different between techniques and showed a positive correlation between them (r=0.826) (P<0.01). BurH-cool provoked the lowest temperature rise and BurFGL the highest (P<0.01). Temperature rises were higher with DiscL than with BurH and BurL (P<0.01), which showed no statistical differences between them (P>0.05). The fastest technique was BurH-cool followed by BurL, BurH, DiscL and BurFGL (P<0.01). CONCLUSION: BurH-cool, BurH and BurL are safe adhesive removal techniques, whereas DiscL and BurFGL may damage pulp tissues. Time spent on adhesive removal has direct effect on temperature rise in the pulp chamber.

Eruption rates of lower second premolars at different development stages evaluated with cone-beam computed tomography.

OBJECTIVE: To evaluate and compare the eruption rates of lower second premolars (LPm2) at different developmental stages using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: Retrospectively, 31 individuals (9.77 ± 1.25 years) had their LPm2 scored according to the Demirjian method, and afterwards they were split into three groups according to developmental stage, as follows: D = complete-formed crowns; E = root length less than crown height; and F = root length greater than or equal to crown height. Linear distances from the LPm2 crown tip to the anatomical reference line (ARL) and to the occlusal plane line (OPL) were measured in paired CBCT scans (T1, T2), taken with an average interval of 8.6 months between them. Eruption rates (mm/y) were calculated and then compared between groups. RESULTS: Eruption rates were greater for LPm2 at stage F than at stages D or E (P < .01) regardless of whether they were measured from the ARL (D = 2.84 mm/y; E = 2.55 mm/y; F = 5.38 mm/y) or from the OPL (D = 1.82 mm/y; E = 2.02 mm/y; F = 5.26 mm/y). Eruption rates evaluated from the ARL and the OPL had no statistically significant differences (P = .052), and a positive correlation (r = .79, P < .001) between them was observed. CONCLUSIONS: LPm2 at Demirjian stage F showed greater eruption rates than at stages D or E, regardless of whether rates were measured from the ARL or the OPL. Faster eruption is expected for LPm2 at stage F. Evaluation of the LPm2's developmental stage using CBCT can aid in clinical decision making regarding the correct timing for intervention.

Analysis of the Influence of Food Colorings in Esthetic Orthodontic Elastomeric Ligatures.

PROPOSITION: The purpose of this study was to evaluate in vitro the color changes of esthetic orthodontic elastomeric ligatures of different shades when exposed to four food colorings commonly found in the diet of patients. MATERIALS AND METHODS: The sample consisted of esthetic orthodontic elastomeric ligatures in the colors pearl, pearl blue, pearl white and colorless, which were immersed for 72 hours in five different solutions: distilled water (control group), coffee, tea, Coca-Cola ® and wine. The color changes of the esthetic orthodontic elastomeric ligatures were measured with the aid of a spectrophotometer, at T1 - as provided by the manufacturer; and T2 - after colorings process. RESULTS: The results indicated that the esthetic orthodontic elastomeric ligatures of all initial hues are susceptible to pigmentation. Among the evaluated colors, all changed the finished look and the color of the samples tested. In ascending order, the color of the samples was as follows: distilled water, Coca-Cola®, black tea, wine and coffee. CONCLUSION: The substances that have a greater potential for pigmentation in esthetic orthodontic elastomeric ligatures were black tea, wine and coffee, respectively. All shades of esthetic orthodontic elastomeric ligatures are susceptible to color change.

Orthodontic treatment of a mandibular incisor fenestration resulting from a broken retainer.

This article describes the orthodontic relapse with mandibular incisor fenestration in a 36-year-old man who had undergone orthodontic treatment 21 years previously. The patient reported that his mandibular 3 × 3 bonded retainer had been partially debonded and broken 4 years earlier. The mandibular left lateral incisor remained bonded to the retainer and received the entire load of the incisors; consequently, there was extreme labial movement of the root, resulting in dental avulsion. As part of the treatment, the root was repositioned lingually using a titanium-molybdenum segmented archwire for 8 months, followed by endodontic treatment, an apicoectomy, and 4 months of alignment and leveling of both arches. The treatment outcomes were excellent, and the tooth remained stable, with good integrity of the mesial, distal, and lingual alveolar bones and periodontal ligament. The 1-year follow-up showed good stability of the results.

Change in the pulp chamber temperature with different stripping techniques.

BACKGROUND: The aim of this study is to evaluate the change in pulp chamber temperature during the stripping technique. METHODS: Seventy-eight proximal surfaces of 39 extracted human teeth were stripped by two techniques: double-sided perforated stripping disk (PSD) and handheld stripper (HS). The teeth were divided into three groups: incisors (group 1), premolars (2), and molars (3). A J type thermocouple was inserted into the pulp chamber for temperature evaluation during the stripping procedure. RESULTS: Temperature rise was observed in all groups. The average temperature increase for the incisors was 2.58°C (±0.27°C) with PSD and 1.24°C (±0.3°C) with HS; for the premolars, 2.64°C (±0.29°C) with PSD and 0.96°C (±0.39°C) with HS; and for the molars, 2.48°C (±0.38°C) with PSD and 0.92°C (±0.18°C) with HS. There was significant difference (p<0.001) in pulp temperature variation among the stripping techniques evaluated. Greater variations in the temperature were observed for the stripping technique with PSD for all groups (3.1°C in incisors and premolars, 3.2°C in molars). Stripping performed with HS had minor differences in pulp temperature (1.7°C in incisors, 1.9°C in premolars, and 1.2°C in molars) than those in PSD group. However, the temperature variation was less than the critical threshold (5.5°C) in all groups. The results for teeth group comparison showed no significant difference in the temperature variation. CONCLUSIONS: The stripping technique with PSD produced significant increase in pulp temperature, with no differences between the types of teeth. However, it may not be clinically relevant, and both stripping techniques can be used safely.

Sagittal changes in lower incisors by the use of lingual arch.

OBJECTIVE: The objective of this study was to evaluate a sagittal variation on the lower incisors with the use of the lingual arch on the transition from mixed to permanent dentition. METHODS: The sample was constituted of 44 Caucasian patients (26 girls and 18 boys), divided in two groups: CG, control group, monitoring the lower arch space with no orthodontic/orthopedic treatment during the rated period (n = 14); EG, experimental group, presenting anterior inferior mild crowding and installation of the lingual arch for space maintenance (n = 30). The position of the lower incisors was analyzed on computerized cephalometric tracings performed at the beginning of the monitoring (T1) and at the end, on the permanent dentition (T2). In order to evaluate the position of the incisors it was used Tweed and Steiner measurements: IMPA, 1.NB and 1-NB. The alterations were analyzed through the "t" test for paired samples, while the differences between the groups were analyzed through the "t" test for independent samples, as for sexual dimorphism. RESULTS: The values in T2 were greater in relation to T1 for all measurements on EG (IMPA, p = 0.038; 1.NB, p = 0.007 and 1-NB, p < 0.0001). On comparing the differences (T2-T1) between CG and EG, it can be gauged differences significantly superior for measure 1.NB (p = 0.002) and 1-NB (p < 0.0001) on EG. There was no statistically significant difference between genres. CONCLUSIONS: It was concluded that the lower incisors were projected after using the lingual arch to control the space on the transition from mixed to permanent dentition, however, within acceptable standards, not having difference between genres.

How to predict the timing of eruption of mandibular second premolars.

OBJECTIVE: To evaluate the relationship between the stages of dental formation and the timing of eruption of mandibular second premolars. MATERIALS AND METHODS: The sample comprised panoramic radiographs of 25 children, 7 to 12 years old, observed by space supervision during development of dentition. The initial radiograph (T1) was taken in the mixed dentition period and the progress radiograph (T2) close to the eruption of mandibular second premolars. The stages of dental formation were determined by the proportion between crown length and total length (CL/TL) as well by the Simpson and Kunos index. Average values between right and left sides (35, 45) were correlated to the time elapsed until dental eruption (T2-T1). Statistical analysis was performed by Pearson correlation analysis. RESULTS: The proportion CL/TL presented higher correlation index with time to eruption than the Simpson and Kunos index. The linear regression equation for prediction of timing of eruption showed high coefficient of determination, low deviation, and good accuracy. According to survival analysis, mean deviation at 95% confidence level was between 3.6 and 6.4 months. There was no difference in contralateral measurements, with high intraclass correlation coefficient for both CL/TL proportion and Simpson and Kunos index. CONCLUSIONS: More advanced stages of dental formation indicate less time until dental eruption. The strong correlation with crown length/total length proportion (CL/TL) provides a linear regression equation for prediction of the timing of eruption of mandibular second premolars.

Indirect bonding with thermal glue and brackets with positioning jigs.

In orthodontics the precise location of bracket placement on the teeth is a goal in order to individualize and optimize treatment outcome. The authors will describe the indirect bonding procedure with thermal glue transfer tray and brackets with positioning jigs for precise bracket placement.

Immediate effects of rapid maxillary expansion with Haas-type and hyrax-type expanders: a randomized clinical trial.

INTRODUCTION: The purposes of this study were to evaluate and compare the immediate effects of rapid maxillary expansion (RME) in the transverse plane with Haas-type and hyrax-type expanders by using cone-beam computed tomography. METHODS: A sample of 33 subjects (mean age, 10.7 years; range, 7.2-14.5 years) with transverse maxillary deficiency were randomly divided into 2 groups: Haas (n = 18) and hyrax (n = 15). All patients had RME with an initial activation of 4 quarter turns followed by 2 quarter turns per day until the expansion reached 8 mm. Cone-beam computed tomography scans were taken before expansion and at the end of the RME phase. Maxillary transversal measurements were compared by using the mixed analysis of variance (ANOVA) model and the Tukey-Kramer method. RESULTS: RME increased all maxillary transverse dimensions (P <0.0001). There was less expansion at skeletal than dental levels. The hyrax group had greater statistically significant orthopedic effects and less tipping tendency of the maxillary first molars compared with the Haas group. CONCLUSIONS: Both appliances were efficient in correcting a transverse maxillary deficiency. The pure skeletal expansion was greater than actual dental expansion. The hyrax-type expander produced greater orthopedic effects than did the Haas-type expander, but this effect was less than 0.5 mm per side and might not be clinically significant.

Can we add chlorhexidine into glass ionomer cements for band cementation?

OBJECTIVE: To test if the addition of chlorhexidine digluconate (CHD) might influence the mechanical properties and antibacterial properties of two different conventional glass ionomer cements (GICs) used for band cementation. MATERIALS AND METHODS: Two commercial brands of conventional GICs were used: Ketac Cem Easymix (3M/ESPE, St Paul, Minn) and Meron (Voco, Cuxhaven, Germany). The cements were manipulated in their original composition and also with 10% and 18% CHD in the liquid to create a total of six groups. Diametral tensile strength, compressive strength, microhardness, shear bond strength, and antibacterial effects in 5, 45, and 65 days against Streptococcus mutans were tested in all groups, and the data were submitted to statistical analyses. RESULTS: There were no significant differences between the groups of the same material in diametral tensile, compressive strength, and shear bond strength (P > .05). There was significant improvement in the microhardness to the Ketac Cem Easymix (P < .001). GICs with the addition of CHD showed significant inhibition of S. mutans growth in comparison with the control groups at the three time points evaluated (P < .001). The addition of 18% CHD resulted in higher bacterial inhibition (P < .001). CONCLUSIONS: The addition of chlorhexidine digluconate to conventional GICs does not negatively modify the mechanical properties and may increase the antibacterial effects around the GICs even for relatively long periods of time.

Infrared laser therapy after surgically assisted rapid palatal expansion to diminish pain and accelerate bone healing.

The aim of this study was to illustrate how gallium arsenite aluminum diode laser (824 nm) irradiation can reduce postsurgical edema and discomfort and accelerate sutural osseous regeneration after surgically assisted rapid palatal expansion (SARPE). An adult patient with an 8-mm transverse maxillary discrepancy was treated with SARPE. Infrared laser therapy was started on the 7th postoperative day, with a total of eight sessions at intervals of 48 hours. The laser probe spot had a size of 0.2827 cm2 and was positioned in contact with the following (bilateral) points: infraorbital foramen, nasal alar, nasopalatine foramen, median palatal suture at the height of the molars, and transverse palatine suture distal to the second molars. The laser was run in continuous mode with a power of 100 mW and a fluency of 1.5 J/cm2 for 20 seconds at each point. Subsequently, an absence of edema and pain was observed. Further, fast bone regeneration in the median palatal suture could be demonstrated by occlusal radiographs. These findings suggest that laser therapy can accelerate bone regeneration of the median palatal suture in patients who have undergone SARPE.

Natural changes of the maxillary first molars in adolescents with skeletal Class II malocclusion.

INTRODUCTION: The objective of this study was to evaluate natural changes in maxillary posterior alveolar height (MPAH) and axial inclination of the maxillary first molars (AIMFM) in subjects with Class II malocclusion to determine the validity of predictive equations. METHODS: Longitudinal records of 30 untreated white subjects (13 girls, 17 boys) with skeletal Class II malocclusion were collected at ages 9, 12, 14, and 16 years. They had participated in the Burlington Growth Centre study, and cephalograms were analyzed with Dentofacial Planner Plus software (version 2.0, Dentofacial Planner, Toronto, Ontario, Canada). Serial means were compared with the Bonferroni post-hoc test (P <0.05). Predictive equations were obtained and studied with the analysis of agreement. RESULTS: Gradually, means of MPAH had statistical increments with sexual dimorphism from 14 to 16 years of age. A distal mean of AIMFM was found at 9 years of age that decreased significantly during growth, with sexual dimorphism between the ages of 9 and 12 years. Changes in AIMFM varied among subjects in distinct stages. Values of MPAH were predicted with high validity at intervals of 3 years or longer, whereas estimations for AIMFM were unreliable. CONCLUSIONS: In this study group, there was significant alveolar growth, with a natural tendency to upright the distal inclination at the maxillary first molars.

Dentoskeletal effects of maxillary protraction in cleft patients with repetitive weekly protocol of alternate rapid maxillary expansions and constrictions.

OBJECTIVE: To evaluate the amount of maxillary protraction with face mask in complete unilateral cleft lip and palate patients submitted to two distinct rapid maxillary expansion (RME) protocols. MATERIAL AND METHODS: The sample consisted of 20 individuals (nine boys and 11 girls; mean age of 10.4 +/- 2.62 years) with unilateral complete cleft lip and palate who had a constricted maxilla in the vertical and transverse dimensions. Ten patients underwent 1 week of RME with screw activation of one complete turn per day, followed by 23 weeks of maxillary protraction (group 1). The other 10 patients underwent 7 weeks of alternate rapid maxillary expansion and constriction, with one complete turn per day, followed by 17 weeks of maxillary protraction (group 2); both groups underwent a total of 6 months of treatment. Cephalometric measurements were taken at different times: pretreatment (T1), soon after RME (T2), and after 6 months of treatment (T3). Each measurement was analyzed with mixed models for repeated measures, and the covariance structure chosen was compound symmetry. RESULTS: The maxilla displaced slightly forward and downward with a counterclockwise rotation; the mandible rotated downward and backward, resulting in an increase in anterior facial height; the sagittal maxillomandibular relationship was improved; the maxillary molars and incisors were protruded and extruded; and the mandibular incisors were retroclined. CONCLUSION: There was no significant difference between the groups in evaluation time.

Surgically assisted rapid maxillary expansion combined with maxillary protraction in an adult: a patient report.

The aim of this article is to discuss an alternative treatment for adult patients who have a dental or skeletal Class III relationship. A 20-year-old woman presented with a dental and skeletal Class III relationship and a transverse maxillary deficiency. Surgically assisted rapid maxillary expansion was followed by maxillary protraction with a face mask and orthodontic treatment with standard edgewise technique. At the end of treatment, a Class I molar and canine relationship was attained with an adequate transverse intercuspation and improvement of the patient's facial profile.

Molar changes with cervical headgear alone or in combination with rapid maxillary expansion.

OBJECTIVE: To test the hypothesis that there is no difference in the distal movement of the maxillary first permanent molars when cervical headgear is used alone or in combination with rapid maxillary expansion. MATERIALS AND METHODS: The sample was composed of 36 subjects (aged 9 to 13 years), treated in the Faculty of Dentistry, Pontifícia Universidade Cat;aaolica, Rio Grande do Sul, Brazil. The individuals were in good health and in their pubertal growth period. All had Class II division 1 malocclusion. The patients were divided into two groups: group 1 (22 subjects), Class II, with a normal transverse maxilla treated with cervical traction headgear (HG) 400 g 12 h/d, and group 2 (14 subjects), Class II maxillary transverse deficiency treated with rapid maxillary expansion plus cervical traction headgear (RME + HG). An additional group 3 (17 subjects) served as a control group and included individuals with the same characteristics. All subjects had two lateral cephalograms: initial (T1) and progress (T2), taken 6 months later. Differences between T1 and T2 were compared with the Student's t-test, and three groups were compared by the analysis of variance and Tukey multiple comparison test. RESULTS: Results showed greater distal tipping and greater distal movement of the first permanent molars in group 1 (HG) than in group 2 (RME + HG), P < .05. No extrusion of first permanent molar occurred in either group (P > .05). CONCLUSION: The hypothesis was rejected. Cervical traction headgear alone produced greater distal movement effects in maxillary first permanent molars when compared with rapid maxillary expansion associated with cervical headgear.

Soft-tissue changes during facial growth in skeletal Class II individuals.

INTRODUCTION: In orthodontic treatment, a harmonious soft-tissue profile can be difficult to achieve; the thickness of the soft tissues can vary greatly, and changes with growth and treatment can be difficult to predict. The purpose of this study was to investigate changes in the thickness and the length of the soft tissues of the nose, upper and lower lips, and chin due to growth from 6 to 16 years of age. METHODS: Cephalograms of 36 subjects (22 boys, 15 girls) with skeletal Class II malocclusions were analyzed. They participated in the Burlington Growth Study, and longitudinal records had been collected at ages 6, 9, 12, 14, and 16 years. The cephalograms were digitized and analyzed with Dentofacial Planner Plus (version 2.0; Dentofacial Software, Toronto, Ontario, Canada) software. Statistical analysis was performed with the nonparametric Friedman test, and comparisons among means were made with 1-way ANOVA software. RESULTS: All structures showed some growth at all stages. The nose showed the greatest increases in thickness and length in both sexes. There was sexual dimorphism at 16 years, with higher values for boys. Upper lips tended to reduce in the girls. Upper lip length showed slight increases, and base of the upper lip showed small increases for both sexes. The lower lip had moderate increases in all measurements, and its thickness showed sexual dimorphism at almost all ages. The soft tissues of the chin increased in both thickness and length, with no sexual dimorphism.