Dehiscence and buccal bone thickness after rapid maxillary expansion in young patients with unilateral cleft lip and palate.

INTRODUCTION: The present study aimed to evaluate the consequences of rapid maxillary expansion in the buccal bone thickness and dehiscence of subjects with unilateral cleft lip and palate. METHODS: This prospective cohort study consisted of 30 participants, 20 males and 10 females, between 8 and 15 years old. Participants were allocated into 3 groups, according to the type of maxillary constriction, and were treated with different types of expanders: G1, hyrax; G2, fan-type; G3, inverted mini-hyrax. Cone-beam computed tomography scans were performed immediately before treatment and after 90 days of retention. Linear measurements were obtained by the same calibrated and blinded examiner. RESULTS: An average of 0.8 mm decrease in buccal bone thickness (P <0.001) and a 0.5 mm increase in dehiscence (P <0.001) were observed. There was no significant difference between the cleft and noncleft side for all variables (P >0.05), as there was no significant difference between groups (P >0.05). CONCLUSION: The findings in this study allow the conclusion that the orthopedic forces of rapid maxillary expansion lead to a decrease in the posterior buccal bone volume in unilateral cleft lip and palate patients.

The impact of rapid maxillary expansion on maxillary first molar root morphology of cleft subjects.

OBJECTIVES: The aim of this prospective cohort study was to determine the effects of rapid maxillary expansion (RME) on the first molar roots of cleft lip and palate subjects along different root development stages. MATERIALS AND METHODS: Thirty participants with unilateral cleft lip and palate were divided into three groups (n = 10), according to the type of expander used: Hyrax, iMini and Fan-type. A cone beam CT scan was performed before (T1) and 3 months after stabilization of the appliance (T2). Measurements of root lengths of the first permanent maxillary molars were taken to evaluate root development and external apical root resorption (EARR). RESULTS: Roots presenting open apexes before treatment exhibited a statistically significant increase in root length after treatment (P < .001). Conversely, there were no significant changes in the root length of roots that had closed apexes at the beginning of treatment (P > .05). Furthermore, there were no differences among groups, or correlation between cleft side and gender was found vis-à-vis to changes in the root length (p > .05). CONCLUSIONS: Orthopaedic forces of RME were neither able to interrupt the root development process nor to cause EARR in cleft subjects. CLINICAL RELEVANCE: As the RME is the most common orthodontic procedure in patients with cleft lip and palate, understanding its impact on dental structures is of fundamental importance.

Effects of angiotensin II type I receptor blocker losartan on orthodontic tooth movement.

INTRODUCTION: Drugs that block the renin-angiotensin system (RAS) are widely used for treating hypertension, heart and kidney failure, and the harmful effects of diabetes. Components of the RAS have been identified in various organs, but little is known of their effects on bone remodeling. The aim of this study was to evaluate whether the blockage of the RAS influences strain-induced bone remodeling in a model of orthodontic tooth movement. METHODS: An orthodontic appliance was placed in C57BL6/J mice that were randomly divided into 2 groups: vehicle-treated mice (VH) and mice treated with losartan (an angiotensin II receptor blocker). Orthodontic tooth movement and the number of tartrate-resistant acid phosphatase-positive cells were determined by histopathologic analysis. The expression of mediators involved in bone remodeling was evaluated by quantitative real-time polymerase chain reaction. Blood pressure was measured before and during the experimental period. RESULTS: Orthodontic tooth movement and tartrate-resistant acid phosphatase-positive cells were significantly reduced in the losartan group compared with the VH group. mRNA levels of osteoclast markers (RANK, RANKL, cathepsin K, and metalloproteinase 13) were lower in the losartan mice than in the VH group, whereas the expressions of osteoblast markers and negative regulators of bone resorption (periostin, dentin matrix protein, alkaline phosphatase, collagen 1A1, semaphorin 3A3, metalloproteinase 2, and osteoprotegerin) were higher in the VH group. CONCLUSIONS: Blockage of the RAS system decreases osteoclast differentiation and activity and, consequently, results in decreased strain-induced bone remodeling in orthodontic tooth movement.

An alternative clinical approach to achieve greater anterior than posterior maxillary expansion in cleft lip and palate patients.

Cleft lip and palate patients commonly present maxillary constriction, particularly in the anterior region. The aim of this case report was to describe an alternative clinical approach that used a smaller Hyrax screw unconventionally positioned to achieve greater anterior than posterior expansion in patients with complete unilateral cleft lip and palate. The idea presented here is to take advantage of a reduced dimension screw to position it anteriorly. When only anterior expansion was needed (patient 1), the appliance was soldered to the first premolar bands and associated to a transpalatal arch cemented to the first molars. However, when overall expansion was required (patient 2), the screw was positioned anteriorly, but soldered to the first molar bands. Intercanine, premolar, and first molar widths were measured on dental casts with a digital caliper. Pre-expansion and postexpansion radiographs and tomographies were also evaluated. A significant anterior expansion and no intermolar width increase were registered in the first patient. Although patient 2 also presented a greater anterior than posterior expansion, a noteworthy expansion occurred at the molar region. The alternative approach to expand the maxilla in cleft patients reported here caused greater anterior than posterior expansion when the Mini-Hyrax was associated to a transpalatal arch, and its reduced dimension also minimized discomfort and facilitated hygiene.

Dental arch dimensional changes after adenotonsillectomy in prepubertal children.

INTRODUCTION: The purposes of this study were to investigate the dental arch changes after adenotonsillectomies in prepubertal children and to compare the dental arch dimensions of mouth-breathing and nasal-breathing children. METHODS: The sample included 49 prepubertal severely obstructed mouth-breathing children and 46 prepubertal nasal-breathing children. Twenty-four of the 49 mouth-breathing children had an adenotonsillectomy and composed the adenotonsillectomy subgroup. The 25 children in whom the mouth-breathing pattern was unchanged during the 1-year study period composed the control subgroup. RESULTS: The mouth-breathing children showed a deeper palatal vault, a larger mandibular width, and a larger mandibular arch length in comparison with the nasal-breathing children. After airway clearance, the adenotonsillectomy group showed a significant maxillary transverse width gain compared with the control subgroup. The control subgroup showed a significant deepening of the palatal height when compared with the adenotonsillectomy subgroup after 1 year. CONCLUSIONS: The adenotonsillectomy subgroup had a significantly different pattern of arch development compared with the untreated controls. After adenotonsillectomy, the mouth-breathing children showed greater maxillary transverse development than did the controls. The palatal vault deepened in the untreated children. The mouth-breathing children showed a deeper palatal vault, a larger mandibular width, and a larger mandibular arch length in comparison with the nasal-breathing children.

Dentoskeletal effects of 3 maxillary expanders in patients with clefts: A cone-beam computed tomography study.

INTRODUCTION: The purpose of this study was to evaluate the skeletal and dental changes in the maxillae of patients with clefts treated with 3 expanders: hyrax, fan-type, and inverted mini-hyrax supported on the first premolars. METHODS: Thirty patients with unilateral cleft lip and palate with transverse maxillary deficiency were divided into 3 groups, according to the type of expander that they used. Cone-beam computed tomography images were taken before and 3 months after expansion, and the paired t test was used to evaluate the changes in each group. RESULTS: The subjects in the inverted mini-hyrax group showed significant forward displacement of the maxilla (P <0.05). On the transversal plane, the hyrax group showed greater expansion in the posterior region than in the anterior region (P <0.05). However, the fan-type and the inverted mini-hyrax groups showed significantly greater maxillary expansion anteriorly than posteriorly (P <0.05). There was a greater tendency for buccal inclination of the supporting teeth when the fan-type was used. The cleft and the noncleft sides expanded symmetrically with all appliances, and there was no difference in dental tipping between these sides (P >0.05). CONCLUSIONS: The hyrax expander showed better results for cleft patients requiring anterior and posterior maxillary expansion. The inverted mini-hyrax most effectively restricted posterior expansion, optimizing anterior expansion without causing as much buccal tipping of the supporting teeth as did the fan-type.

Comparison of 3D-printed and laboratory-fabricated Hyrax on stress distribution and displacement of the maxillary complex: a 3D finite element study.

OBJECTIVE: To analyze and compare the effects of a traditional laboratory-fabricated Hyrax expander (T-Hyrax) and two different 3D-printed Hyrax expander models relative to tension points, force distribution, and areas of concentration in the craniofacial complex during maxillary expansion using finite element analysis. MATERIALS AND METHODS: Three maxillary expanders with similar designs, but various alloys were modeled: a T-Hyrax, a fully printed Hyrax (F-Hyrax), and a hybrid printed Hyrax (H-Hyrax). The stress distributions and magnitude of displacements were assessed with a 5 mm expansion in a symmetrical finite element model. The areas of interest included the teeth, alveolar processes, midpalatal suture, nasal complex, circummaxillary sutures (CS), and the expanders themselves. RESULTS: The highest stress value (29.2 MPa) was found at the midpalatal suture of the F-Hyrax, while the lowest stress (0.90 MPa) was found at the temporozygomatic suture in the T-Hyrax. On average, the F-Hyrax increased stress at the CS by 24.76% compared with the T-Hyrax and H-Hyrax. The largest displacements were found at the upper incisor (U1) and anterior nasal spine (ANS). The findings indicated an average increase of 12.80% displacement at the CS using the F-Hyrax compared to the T-Hyrax. CONCLUSION: The F-Hyrax exerts more stress and displacement on the maxilla than both the T-Hyrax and H-Hyrax, where the weak link appears to be the solder joint.

Studying Orthodontic Tooth Movement in Mice.

Orthodontic tooth movement (OTM) represents a dynamic process in which the alveolar bone undergoes resorption at compression sites and deposition at tension sites, orchestrated by osteoclasts and osteoblasts, respectively. This mechanism serves as a valuable model for studying various aspects of bone adaptation, including root resorption and the cellular response to mechanical force stimuli. The protocol outlined here offers a straightforward approach to investigate OTM, establishing 0.35 N as the optimal force in a mouse model employing a nickel-titanium (NiTi) coil spring. Utilizing micro-computed tomography analysis, we quantified OTM by assessing the discrepancy in the linear distance at the cement-enamel junction. The evaluation also included an analysis of orthodontic-induced inflammatory root resorption, assessing parameters such as root mineral density and the percentage of root volume per total volume. This comprehensive protocol contributes to advancing our understanding of bone remodeling processes and enhancing the ability to develop effective orthodontic treatment strategies.

Bone thickness and height of the buccal shelf area and the mandibular canal position for miniscrew insertion in patients with different vertical facial patterns, age, and sex.

OBJECTIVES: The objectives of this article were the following: (1) to analyze bone thickness and height (BTH) of the buccal shelf area (BS) quantitatively in four different potentially eligible sites for miniscrew insertion; (2) to compare and contrast BTH and the changes in spatial position of the inferior alveolar nerve canal (IANC); and (3) to assess differences with age among vertical facial patterns (hypodivergent, normodivergent, and hyperdivergent) and well as by sex. MATERIALS AND METHODS: Cone-beam computed tomography scans of 205 individuals (110 women and 95 men) were divided into groups according to age, vertical facial pattern, and sex. The BTH of the BS and the BTH to the IANC were measured in the mesial and distal roots of the first and second molars. RESULTS: BTH progressively increased in a posterior direction (P < .001), while BTH to the IANC increased and decreased (P < .001) for thickness and height, respectively, in the same direction in all age groups, for the three different vertical facial patterns, and in both sexes. Women showed significantly less BTH to the IANC (P < .002). Hypodivergent patients had greater BTH (P < .024) and a smaller bone height to the IANC (P < .018) only in the first molar region. Patients over 40 years of age had lower bone height in the second molar area (P < .003). CONCLUSIONS: The ideal place for BS miniscrew insertion is the region of the distal root of the second molars, regardless of facial pattern, sex, and age. The BS in women has less BTH and less BTH to the IANC.

Role of CCR2 in orthodontic tooth movement.

INTRODUCTION: Cytokines and chemokines regulate bone remodeling during orthodontic tooth movement. CC chemokine ligand 2 (CCL2) is involved in osteoclast recruitment and activity, and its expression is increased in periodontal tissues under mechanical loading. In this study, we investigated whether the CC chemokine receptor 2 (CCR2)-CCL2 axis influences orthodontic tooth movement. METHODS: A coil spring was placed in CCR2-deficient (CCR2(-/-)), wild-type, vehicle-treated, and P8A-treated (CCL2 analog) mice. In a histopathologic analysis, the amounts of orthodontic tooth movement and numbers of osteoclasts were determined. The expression of mediators involved in bone remodeling was evaluated by real-time polymerase chain reaction. RESULTS: Orthodontic tooth movement and the number of TRAP-positive cells were significantly decreased in CCR2(-/-) and P8A-treated mice in relation to wild-type and vehicle-treated mice, respectively. The expressions of RANKL, RANK, and osteoblasts markers (COL-1 and OCN) were lower in CCR2(-/-) than in wild-type mice. No significant difference was found in osteoprotegerin levels between the groups. CONCLUSIONS: These data suggested a reduction of osteoclast and osteoblast activities in the absence of CCR2. The CCR2-CCL2 axis is positively associated with osteoclast recruitment, bone resorption, and orthodontic tooth movement. Therefore, blockage of the CCR2-CCL2 axis might be used in the future for modulating the extent of orthodontic tooth movement.

Cross-cultural adaptation of a questionnaire assessing the child and parents' expectations of orthodontic treatment in Brazil.

INTRODUCTION: The Sayers and Newton questionnaire was developed in England to assess the child's and parent's expectations about orthodontic treatment. OBJECTIVE: The aim of this study was to carry out the cross-cultural adaptation of the questionnaire for the Brazilian Portuguese language, to test its reliability, and to compare patients' and their parents' expectations of orthodontic treatment. METHODS: After translation and cross-cultural adaptation, the questionnaire was applied to 98 patients (12-14 years), who had been referred for treatment, and their caregivers. The internal consistency of the instrument was assessed by Cronbach's Alpha Coefficient and the test-retest reliability, by Intraclass Correlation Coefficient (ICC). RESULTS: Internal reliability was confirmed by a Cronbach's alpha coefficient of 0.75. Test-retest reliability revealed satisfactory reproducibility (ICC = 0.85). The results showed some significant differences between the expectations of the patients and their caregivers (p < 0.05). There were no significant gender differences (p > 0.05). CONCLUSIONS: The process of cross-cultural adaptation of the Sayers and Newton questionnaire for the Brazilian Portuguese was concluded. This study demonstrated that this instrument is reliable and applicable to assess the child's and parent's expectations about orthodontic treatment in Brazil, and it has acceptable psychometric properties.

Effect of diabetes on orthodontic tooth movement in a mouse model.

Orthodontic tooth movement is achieved by the remodeling of alveolar bone in response to mechanical loading. Type 1 diabetes results in bone remodeling, suggesting that this disease might affect orthodontic tooth movement. The present study investigated the effects of the diabetic state on orthodontic tooth movement. An orthodontic appliance was placed in normoglycemic (NG), streptozotocin-induced diabetes (DB), and insulin-treated DB (IT) C57BL6/J mice. Histomorphometric analysis and quantitative PCR of periodontium were performed. The DB mice exhibited greater orthodontic tooth movement and had a higher number of tartrate-resistant acid phosphate (TRAP) -positive osteoclasts than NG mice. This was associated with increased expression of factors involved in osteoclast activity and recruitment (Rankl, Csf1, Ccl2, Ccl5, and Tnfa) in DB mice. The expression of osteoblastic markers (Runx2, Ocn, Col1, and Alp) was decreased in DB mice. Reversal of the diabetic state by insulin treatment resulted in morphological findings similar to those of NG mice. These results suggest that the diabetic state up-regulates osteoclast migration and activity and down-regulates osteoblast differentiation, resulting in greater orthodontic tooth movement.

Modified Arnold expander: an alternative for mandibular arch expansion.

INTRODUCTION: Due to the anatomical constraints of the mandible, mandibular dental arch usually serves as a guideline to determine the required changes in the maxillary transverse dimension. The Schwarz appliance and the Lip Bumper are the traditional orthodontic appliances for mandibular arch expansion in patients with borderline amounts of crowding, and/or transverse discrepancy. However, they often require patient cooperation, which may be a concern for orthodontists in daily practice. OBJECTIVES: This article illustrates a simple fixed orthodontic device as an alternative to achieve mandibular arch expansion in patients with moderate tooth-size/arch-length discrepancy. The four reported cases refer to 8 to 10-year-old patients in the mixed dentition, with an Angle Class I or Class II malocclusion, transverse deficiency in both arches, moderate crowding and/or posterior crossbite, combined with compromised smile aesthetics. The patients were treated with rapid maxillary expansion (RME) using Hass expander appliance and the modified Arnold expander (MAE). CONCLUSION: This low-cost compliance-free orthodontic appliance provided dentoalveolar decompensation by means of uprighting the posterior teeth, with minimal or no adjustments during treatment. The final results were achieved in only three to four months, and fulfilled all treatment objectives, such as an increase in the arch perimeter and width, and a better teeth alignment.

Frictionless Segmented Mechanics for Controlled Space Closure.

The treatment of incisor protrusion by means of tooth extraction can be challenging for orthodontists, especially during the space closure phase. Moreover, the level of difficulty may increase when anterior movement of the posterior teeth is not desirable. Treatment alternatives may include the use of mini implants, mini plates, and extraoral devices to reinforce anchorage; however, some patients may oppose these aggressive methods. This article describes the use of frictionless segmented mechanics that provide differential moments for controlled space closure during full retraction of the incisors without using extraoral forces or temporary anchorage devices.

How a Discrepancy Between Centric Relation and Maximum Intercuspation Alters Cephalometric and Condylar Measurements.

OBJECTIVE: The authors' objective was to determine, by means of cone-beam computed tomography (CBCT), if there is a significant difference between the cephalometric and condylar measurements obtained in maximum intercuspation (MIP) and those obtained in centric relation (CR), which would interfere in orthodontic diagnosis and planning. METHODS: The sample consisted of 30 randomly selected patients (15 men and 15 women, mean age 14 years, CR ≠ MIP between 1 mm and 2 mm) who had undergone orthodontic treatment. This retrospective study used CBCT scans, one in MIP and the other in CR. Cephalometric measurements and sagittal, axial, and vertical condylar variations between the CR and MIP positions were analyzed in a tridimensional (3D) imaging software. RESULTS: Patients with a small CR-MIP discrepancy (<2 mm) presented significant differences in the cephalometric analysis carried out in CR and MIP, although these differences might be of low clinical significance. The condyle-fossa relationships in sagittal, coronal, and axial planes did not seem to be relevant, because only one measurement presented significant change between CR and MIP positions. CONCLUSIONS: Class II malocclusion in patients with a large CR-MIP discrepancy may be exacerbated in the CR position, which may in turn increase treatment difficulty. In these cases, not only must cephalometrics be registered in CR, but dental casts and photographs of the patient are needed to permit orthodontists to plan an appropriate treatment.

Three-dimensional nasal septum and maxillary changes following rapid maxillary expansion in patients with cleft lip and palate.

OBJECTIVES: To determine the three-dimensional changes of the nasal septum (NS), alveolar width, alveolar cleft volume, and maxillary basal bone following rapid maxillary expansion (RME) in consecutive patients with unilateral cleft lip and palate (UCLP). MATERIALS AND METHODS: A retrospective investigation was conducted based on the analysis of cone-beam computed tomography (CBCT) data of 40 consecutive patients with UCLP (mean age 11.1 ± 2.2 years). Scans were acquired prior to RME (T0) and after removal of the expander (T1) before graft surgery. A three-dimensional analysis of the effects of RME on the nasal septum, alveolar width, alveolar cleft volume, and maxillary basal bone was performed. RESULTS: No changes in the NS deviation were observed following RME (P > .05). Significant increases of the alveolar transverse dimension were found in the anterior (14.2%; P < .001) and posterior (7.7%; P < .001) regions as well as in the volume of the alveolar cleft (19.6%; P < .001). No changes in the basal bone dimensions and morphology were observed (P > .05). CONCLUSIONS: Following RME, no changes were observed in the NS and maxillary basal bones of patients with UCLP despite the significant gain in the anterior and posterior alveolar width and the increase of the alveolar cleft defect. Clinicians should be aware that maxillary changes following RME in patients with UCLP are restricted to the dentoalveolar region.

Spontaneous Eruption of Severely Impacted teeth: The Report of Two Cases.

The unerupted and impacted tooth is a common problem and the reason for many orthodontic and pediatric dental referrals, yet the approach to their management is still an area of controversy. This article presents two cases of severely impacted teeth that spontaneously erupted in the maxillary and mandibular arches. The first patient, a 9-year-old girl, presented a severe impaction of mandibular right and left second premolars. The second patient, a 7-year-old girl, presented with a severely impacted maxillary central incisor. In both cases, the teeth spontaneously erupted into excellent positions without surgical procedures and orthodontic traction. This raises important questions concerning the possible treatment options for such teeth as well as the timing of any interceptive treatment. In cases of unerupted or impacted teeth, a multidisciplinary approach is indicated involving orthodontics, paedodontics and oral surgery to establish the optimal treatment plan. Key words:Tooth eruption, tooth, impacted, orthodontics, interceptive, case reports.

Predisposing factors for external apical root resorption associated with orthodontic treatment.

OBJECTIVE: This study aimed to identify possible risk factors for external apical root resorption (EARR) in the maxillary incisors after orthodontic treatment. METHODS: The root length of 2,173 maxillary incisors was measured on periapical radiographs of 564 patients who received orthodontic treatment. The Kappa test was performed to evaluate intraexaminer and interexaminer reproducibility. Multiple binary logistic regression was used to determine the association between EARR and various factors. Odds ratios and 95% confidence intervals were reported. RESULTS: The risk of developing EARR was 70% higher in orthodontic treatment with maxillary premolar extraction (p = 0.004), 58% higher in patients with increased overjet (p = 0.012), 41% lower in two-phase orthodontic treatment (p = 0.037), and 33% lower in patients with deep bite (p = 0.039). The lateral incisors were 54% more likely to develop EARR (p < 0.001), dilacerated roots were 2.26 times more likely to develop EARR (p < 0.001), and for each additional millimeter of root length, the risk of EARR increased by 29% (p < 0.001). CONCLUSIONS: The potential risk factors for EARR after orthodontic treatment included treatment with maxillary premolar extraction, increased overjet at the beginning of treatment, and dilacerated roots.