Application of a 3D Fusion Model to Evaluate the Efficacy of Clear Aligner Therapy in Malocclusion Patients: Prospective Observational Study

BACKGROUND

Investigating the safe range of orthodontic tooth movement is essential for maintaining oral and maxillofacial stability posttreatment. Although clear aligners rely on pretreatment digital models, their effect on periodontal hard tissues remains uncertain. By integrating cone beam computed tomography-derived cervical and root data with crown data from digital intraoral scans, a 3D fusion model may enhance precision and safety.

OBJECTIVE

This study aims to construct a 3D fusion model based on artificial intelligence software that matches cone beam computed tomography and intraoral scanning data using the Andrews' Six Element standard. The model will be used to assess the 3D effects of clear aligners on tooth movement, to provide a reference for the design of pretreatment target positions.

METHODS

Between May 2022 and May 2024, a total of 320 patients who completed clear aligner therapy at our institution were screened; 136 patients (aged 13-35 years, fully erupted permanent dentition and periodontal pocket depth <3 mm) met the criteria. Baseline ("simulation") and posttreatment ("fusion") models were compared. Outcomes included upper core discrepancy (UCD), upper incisors anteroposterior discrepancy (UAP), lower Spee curve deep discrepancy (LSD), upper anterior teeth width discrepancy (UAW), upper canine width discrepancy (UCW), upper molar width discrepancy (UMW), and total scores. Subanalyses examined sex, age stage (adolescent vs adult), and treatment method (extraction vs nonextraction).

RESULTS

The study was funded in May 2022, with data collection beginning the same month and continuing until May 2024. Of 320 initial participants, 136 met the inclusion criteria. Data analysis is ongoing, and final results are expected by late 2024. Among the 136 participants, 90 (66%) were female, 46 (34%) were male, 64 (47%) were adolescents, 72 (53%) were adults, 38 (28%) underwent extraction, and 98 (72%) did not. Total scores did not differ significantly by sex (mean difference 0.01, 95% CI -0.13 to 0.15; P=.85), age stage (mean difference 0.03, 95% CI -0.10 to 0.17; P=.60), or treatment method (mean difference 0.07, 95% CI -0.22 to 0.07; P=.32). No significant differences were found in UCD (mean difference 0.001, 95% CI -0.02 to 0.01; P=.90) or UAP (mean difference 0.01, 95% CI -0.03 to 0.00; P=.06) by treatment method. However, adolescents exhibited smaller differences in UCD, UAW, UCW, and UMW yet larger differences in UAP and LSD (df=134; P<.001). Extraction cases showed smaller LSD, UAW, and UCW but larger UMW differences compared with nonextraction (df=134; P<.001).

CONCLUSIONS

The 3D fusion model provides a reliable clinical reference for target position design and treatment outcome evaluation in clear aligner systems. The construction and application of a 3D fusion model in clear aligner orthodontics represent a significant leap forward, offering substantial clinical benefits while establishing a new standard for precision, personalization, and evidence-based treatment planning in the field.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2400094304, https://www.chictr.org.cn/hvshowproject.html?id=266090&v=1.0.

Periodontal evaluation after maxillary expansion with a tooth-bone-borne expander in growing patients : A randomized clinical trial

PURPOSE

This two-arm parallel randomized controlled trial aimed to evaluate and compare periodontal changes due to rapid maxillary expansion (RME) using tooth-bone-borne and tooth-borne devices in growing patients via clinical examinations and cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

Forty-two eligible patients (aged 11-14 years; transverse maxillary deficiency, posterior crossbite) were screened and divided into two groups based on the treatment received (randomization was performed using computer-generated numeric sequences): hybrid hyrax tooth-bone-borne group (TBB) and hyrax tooth-borne group (TB). The primary outcome was the change in cortical bone thickness (by CBCT). In addition, the clinical attachment level (CAL), gingival recession, and bleeding were assessed. Both examinations were performed before and 3 months after the activation phase. Intergroup comparisons were performed using analysis of covariance (ANCOVA; P < 0.05).

RESULTS

Twenty-one patients (12 girls and 9 boys; mean initial age, 13.3 years) were included in the TBB group and 21 (5 girls and 16 boys; mean initial age, 13.2 years) were included in the TB group. The TB group exhibited a decrease in buccal bone thickness in the first premolars and first molars at all three evaluated levels. Specifically, tooth 14 at 3 mm from the enamel-cement junction showed a significant width reduction (0.7 mm; p < 0.001), accompanied by a notable increase in palatal cortical thickness at 6 mm of enamel-cement junction (1.13 mm; p < 0.001).

CONCLUSIONS

RME resulted in buccal bone thickness reduction at the first premolar with hyrax treatment. In the molar region, both devices resulted in cortical bone alterations that were less pronounced in the TBB group.

Effects of rapid maxillary expansion on anchorage alveolar bone meta-analysis

PURPOSE

Rapid maxillary expansion (RME) is a routine method for correcting transverse maxillary deficiency. This paper investigated the effect of RME on anchorage alveolar bone and examined the differences between micro-implant-assisted RME and conventional RME.

METHODS

Relevant articles were selected from the PubMed, EMBASE and Cochrane Central Register of Controlled Trials databases. Review Manager software (v.5.3) was used for the pooled analysis and Cochran Q and I2 statistic tests were used to assess the heterogeneity.

RESULTS

Following conventional RME, the distal buccal alveolar bone thickness and the mesiobuccal alveolar thickness of the maxillary first molars were significantly reduced. Hyrax (standard mean difference [SMD]: -0.93, 95% confidence interval [CI]: -1.20-0.66) and Haas procedures (SMD: -0.88, 95% CI: -1.40-0.36) significantly reduced the buccal vertical alveolar height of the maxillary first molars. Similar results were obtained for the maxillary first premolars following RME. The thickness of the buccal alveolar bone decreased with conventional RME compared to when using the method assisted by micro-implants.

CONCLUSIONS

Conventional RME can reduce the thickness and vertical height of maxillary alveolar bone, and there is less loss of alveolar bone when using micro-implant-assisted RME. Further research is needed to validate the findings.

Tridimensional Changes in Mandibular Arch after Rapid Maxillary Expansion Therapy: A Clinical Study

Aim: The upper jaw transverse deficit is certainly one of the most common clinical issues in the orthodontic field. It can be due to skeletal or dental factors, and its etiology may be both genetic and environmental. Rapid maxillary expanders (RMEs) are certainly the most effective appliance for upper transverse deficiency correction. The aim of this study was to evaluate the changes that occurred in the mandibular arch during treatment with RMEs in growing subjects by analyzing tridimensional lower digital casts. Materials and Methods: The study group (SG) consisted of 20 subjects (10 M, 10 F; mean age 9.4 ± 2.8 years old) randomly selected at the Department of Orthodontics at the University of Rome, "Tor Vergata". The inclusion criteria were negative posterior transverse interarch discrepancy ≥ 4 mm, mixed dentition phase with first permanent molars erupted, and prepubertal skeletal maturation stage (CS1-2), evaluated on a lateral radiograph through the Cervical Vertebral Maturation method. The SG was compared to an untreated control group (CG) of 20 subjects (10 M, 10 F, mean age 8.7 ± 2.3 years old) enrolled with the same inclusion criteria. The SG was treated by using RMEs. Dental casts of the lower arch were taken at two different times (T0-T1 = 6 months). All the dental casts were scanned with an OrthoXscan (Dentaurum 6mmbh E Co., Ispringen, Germany) and twenty points on the mandibular arch were digitized using Viewbox software. A Student t-test was used to compare the means of the quantitative variables associated with the effect of the device over time T0 and T1. Results: The results show a statistically significant increase (p < 0.05) in the intercanine and the intermolar diameters between the times T0 and T1 when compared to the CG. Conclusions: Rapid maxillary orthopedic expansion may achieve an increase in mandibular intercanine and intermolar diameter.

Evaluation of the dimensional changes in the mandible, condyles, and the temporomandibular joint following skeletal class III treatment with chin cup and bonded maxillary bite block using low-dose computed tomography: A single-center, randomized controlled trial

Background: Insufficient evidence regarding the effects of chincup therapy on the mandibular dimensions and temporomandibular joint (TMJ) structures requires high-quality studies using three-dimensional (3D) imaging. This trial aimed to evaluate the 3D changes in the mandible, condyles, and glenoid fossa after chin cup therapy for skeletal Class III children compared to untreated controls. Methods: A 2-arm parallel-group randomized controlled trial on 38 prognathic children (21 boys and 17 girls), with mean ages 6.63±0.84 years. Patients were recruited and randomized into two equal groups; the experimental group (CC) was treated with occipital-traction chin cups in conjunction with bonded maxillary bite blocks. No treatment was provided in the control group (CON). Low-dose CT images were acquired before (T1) and after achieving  (2-4 mm) positive overjet (T2), and after 16 months apart in both groups. The outcome measures of the condyle-mandibular 3D distances, the condyles-glenoid fossa postional changes, and the quantitative displacement parameters of superimposed 3D models were compared statistically. Paired- and two-sample t-tests were used for intra- and inter-group comparisons, respectively. Results: Overall, 35 patients (18 and 17 in the CC and the CON groups, respetively) were enrolled in the statistical analysis. The mean mandibular and condylar volumes increased significantly by 777.24 mm3 and 1,221.62 mm3, 94.57 mm3, and 132.54 mm3 in the CC and CON groups, respectively. No statistically significant differences were observed between the groups regarding the volumes, superficial areas, and linear changes of the mandible and condyles, and part analysis measurements, except the changes of the relative sagittal and vertical positions of condyles, glenoid fossa, and posterior joint space, which were significantly smaller in the CC group (p<0.05) than the CON group. Conclusions: The chin cup did not affect the mandibular dimensions. Its primary action was confined to the condyles and the TMJ internal dimensions. Clinicaltrials.gov registration: NCT05350306 (28/04/2022).

Changes in the Mandible Following Rapid Maxillary Expansion in Children with Class II Malocclusion: A Systematic Review

Objective: The aim of this systematic review was to determine whether rapid maxillary expansion (RME) allows favorable changes in the mandible during the treatment of class II malocclusion before the growth spurt. Methods: A search of Pubmed/Medline, the Science Direct, and the Google Scholar database was performed. The keywords used were: orthodontics, rapid maxillary expansion, class II, and growing patients. Relevant articles were assessed for quality according to Cochrane guidelines, and then changes in SNA, SNB, ANB, NL-NSL (or SN-SNP.SNA), and ML-NSL (or SN-Go-Gn) relationships were analyzed. Results: The selection process brought forth five articles, including 162 patients (91 females, 71 males) for detailed analysis. The quality of the evidence (GRADE) for comparisons and outcomes was assessed as moderate for SNB and ANB and as low or very low for other variables. Conclusions: The results of this systematic review showed that there is a small body of moderate-quality evidence for statistically and clinically favorable changes in SNB and ANB angles and a small body of low-quality evidence for changes in vertical parameters after RME.

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.

Three-dimensional evaluation of skeletal and dental effects of treatment with maxillary skeletal expansion

INTRODUCTION

The objective was to determine the skeletal and dental changes with microimplant assisted rapid palatal expansion (MARPE) appliances in growing (GR) and nongrowing (NG) patients using cone-beam computed tomography and 3-dimensional imaging analysis.

METHODS

The sample consisted of 25 patients with transverse maxillary discrepancy treated with a maxillary skeletal expander, a type of MARPE appliance. Cone-beam computed tomography scans were taken before and after maxillary expansion; the interval was 6.0 ± 4.3 months. The sample was divided into GR and NG groups using cervical vertebral and midpalatal suture maturation. Linear and angular 3-dimensional dentoskeletal changes were assessed after cranial base superimposition. Groups were compared with independent-samples t test (P <0.05).

RESULTS

Both groups displayed marked transverse changes with a similar ratio of skeletal to dental transverse changes and parallel sutural opening from the posterior nasal spine-anterior nasal spine; a similar amount of expansion occurred in the anterior and the posterior regions of the maxilla. The maxilla expanded skeletally without rotational displacements in both groups. The small downward-forward displacements were similar in both groups, except that the GR group had a significantly greater vertical displacement of the canines (GR, 1.7 ±1.0 mm; NG, 0.6 ± 0.8 mm; P = 0.02) and anterior nasal spine (GR, 1.1 ± 0.6 mm; NG, 0.5 ± 0.5 mm; P = 0.004).

CONCLUSIONS

Treatment of patients with MARPE appliance is effective in GR and NG patients. Although greater skeletal and dental changes were observed in GR patients, a similar ratio of skeletal to dental transverse changes was observed in both groups.

Comparison of changes in skeletal, dentoalveolar, periodontal, and nasal structures after tooth-borne or bone-borne rapid maxillary expansion: A parallel cohort study

INTRODUCTION

This parallel cohort study aimed to assess the dentoalveolar, skeletal, periodontal, and airway effects of tooth-borne (hyrax) and computer-guided miniscrew-supported rapid palatal expansion appliances.

METHODS

Thirty-six subjects were randomly allocated into 2 groups. Eighteen subjects (mean age, 12.2 years; male-to-female ratio, 10:8) were assigned to receive treatment with the hyrax appliance (group A), and 18 subjects were treated with the computer-guided miniscrew-supported appliance (group B). The same type of expansion screw and expansion protocol was used in both groups. Linear and angular measurements of skeletal, dentoalveolar, periodontal, and nasal floor changes were performed on the pretreatment and posttreatment cone-beam computed tomography images (6-month follow-up). Descriptive statistics and the independent Student t test were used for the statistical analysis. Intraoperator reliability was evaluated using a 2 sample t test. The level of significance was P ≤0.05.

RESULTS

Ten subjects were censured because posttreatment cone-beam computed tomography imaging was not performed because of the coronavirus disease 2019 pandemic. In the remaining 26 subjects, increases in linear measurements were observed in both groups. The transversal skeletal increase was greater and statistically significant in the group treated with the bone-borne expander (P ≤0.05). The dentoalveolar transverse diameters were greater in the tooth-supported expander group, with no statistically significant difference between the groups. The buccal inclination of the maxillary first molar was observed in the group with the tooth-borne expander, with a statistically significant difference between the 2 groups. A slight reduction of buccal and palatal thicknesses at the level of the maxillary first molars was observed in both groups, smaller in the skeletal expander group, with a statistically significant difference between the 2 groups only on the right buccal cortical plate. The width of the nasal floor increased more in the group with skeletal expander with a statistically significant difference of 2 mm.

CONCLUSIONS

Computer-guided miniscrew-supported maxillary expanders allowed a greater transversal increase of the nasal-maxillary skeletal structures by reducing the dentoalveolar side effects of the tooth-supported devices.

Three-dimensional oropharyngeal airway changes after facemask therapy using low-dose computed tomography: a clinical trial with a retrospectively collected control group

Aims

This study aimed to evaluate the short-term oropharyngeal airway volumetric changes in growing Class III maxillary-deficient patients treated by facemask without expansion compared with untreated Class III controls, using low-dose computed tomography.

Methods

Eighteen maxillary-deficient children (9 boys, nine girls) with a mean age of 7.81 ± 0.84 years were treated with maxillary bonded bite block and facemask (FM). Pre- (T1) and post-treatment (T2) low-dose CT images were acquired. Sixteen untreated Class III patients with a mean age of 7.03 ± 0.56 years had previously two low-dose CT scans within a one year of follow-up. Volumetric and minimal cross-sectional area measurements were obtained to assess the oropharyngeal airway changes. Quantitative mean, minimum, and maximum displacement of superimposed 3D models were estimated from a point-based analysis. Paired-samples t-tests were used for the intragroup comparisons, and an independent samples t-test and the Mann–Whitney U tests were carried out for the intergroup comparisons.

Results

A statistically significant increase in the total and retropalatal volumes oropharyngeal airway volume were observed in the control group (302.23 ± 345.58 and 145.73 ± 189.22 mm³, respectively). In the FM group, statistically significant increases in the total and retropalatal volumes were observed (738.86 ± 1109.37 mm³ and 388.63 ± 491.44 mm³, respectively). However, no statistically significant differences were found between the two groups, except for the maximum part analysis which was significantly greater in the FM group (p = 0.007).

Conclusions

FM therapy appeared to have no additional effects on the oropharyngeal airway other than those induced by growth.

Novel Digital Measurement Technique to Analyze the Palatine Suture Expansion after Palatine Rapid Maxillary Expansion Technique

The aim of the study was to validate a novel digital measurement method to quantify the volume of the midpalatal suture after rapid maxillary expansion (RME). Material and methods: Eight patients with maxillary skeletal transverse deficiency were submitted to palatine suture expansion using the McNamara orthodontic appliance during a period of nine months. After 30 days of treatment, all patients were exposed postoperatively to a cone-beam computed tomography (CBCT) scan. Afterwards, the scans were uploaded into the three-dimensional orthodontic-planning software to allow the volumetric assessment of the palatine suture expansion through palatine rapid maxillary expansion using a McNamara appliance. The repeatability was analyzed by repeating twice the measures by a single operator and reproducibility was analyzed by repeating three times the measures by two operators, and Gage R&R statistical analysis was performed. Results: The expansion of the midpalatal suture by means of the rapid maxillary expansion technique, in terms of digital volume measurement, showed a repeatability value of 0.09% and between the two operators a reproducibility value of 0.00% was shown. Conclusions: The novel measurement technique demonstrated a high repeatability and reproducibility rate for volume assessment of the palatine suture expansion through palatine rapid maxillary expansion technique.

Does Alt-RAMEC protocol and facemask treatment affect dentoalveolar structures?

OBJECTIVES

To evaluate dentoalveolar changes immediately after the alternate rapid maxillary expansion and constriction (Alt-RAMEC) protocol and facemask (FM) treatment using cone-beam computed tomography images.

MATERIALS AND METHODS

Cone-beam computed tomography images of 20 patients (mean age = 9.64 ± 1.3 years) who received the Alt-RAMEC protocol before FM treatment were retrieved in this retrospective study. Dental and alveolar inclinations, buccal and palatal alveolar bone thickness, and buccal and palatal alveolar bone height changes were measured before treatment (T0), after the Alt-RAMEC protocol (T1), and after FM treatment (T2). Measurements for right and left molars were performed separately. The Shapiro-Wilks test was used to assess the conformity of the parameters to the normal distribution. The paired t-test and repeated measures analysis of variance were used for normally distributed data. The Wilcoxon signed-rank test and Friedman test were used for non-normally distributed data. The Bonferroni correction was used to reduce the chances of obtaining false-positive results. Statistical significance was set at P < .05.

RESULTS

Buccal alveolar bone thickness and alveolar bone inclinations decreased significantly from T1 to T0 and showed no significant change from T2 to T1. The total reduction T2-T0 was statistically significant. The change in palatal alveolar bone thickness was not significant T1-T0 but increased significantly for T2-T1 and T2-T0. Buccal alveolar bone height, palatal alveolar bone height, and molar inclinations increased significantly T1-T0, but there was no significant change T2-T1. The total reduction at T2-T0 was statistically significant.

CONCLUSIONS

The results of this study revealed that the effects of the Alt-RAMEC protocol on dentoalveolar tissues were similar to the changes reported in the literature after rapid palatal expansion.

Comparison of skeletal and dentoalveolar changes between pure bone-borne and hybrid tooth-borne and bone-borne maxillary rapid palatal expanders using cone-beam computed tomography

Objectives:

The objectives of the study were to compare the skeletal, dentoalveolar, and periodontal changes between two types of microimplant-assisted rapid maxillary expansion appliances: The bone-anchored maxillary expanders (BAME) and the tooth-bone-anchored maxillary skeletal expander (MSE).

Materials and Methods:

Thirty-four patients with a transverse maxillary deficiency were divided into two groups; the first group (16 patients, average age 14.9 years) was treated with the MSE appliance, and the second group (18 patients, average age 13.8 years) was treated with the BAME appliance. Cone-beam computed tomography scans were taken at pre-treatment (T1) and immediately post-expansion (T2) to measure the changes in midpalatal suture opening, total expansion (TE), alveolar bone bending, dental tipping (DT), and buccal bone thickness. Data were analyzed using paired t-test and two-sample t-test.

Results:

Midpalatal suture separation was found in 100% of the patients in both groups. The TE at the first molar was 5.9 mm in the MSE group and 4.7 mm in the BAME group. The skeletal contributions were 56% and 83% of TE for the MSE and BAME groups, respectively. Significantly less dental buccal tipping and buccal bone loss were found with the BAME group. The midpalatal suture in both groups exhibited a parallel opening pattern in the axial plane.

Conclusion:

The use of BAME appliance resulted in greater skeletal effects, less dental tipping, and less buccal bone reduction compared to MSE appliance (immediately after maxillary expansion).

Evaluation of Alt-RAMEC With Facemask in Patients With Unilateral Cleft lip and Palate (UCLP) Using Cone Beam Computed Tomography (CBCT) and Finite Element Modeling-A Clinical Prospective Study

OBJECTIVE

Evaluate the effects of alternate rapid maxillary expansion and constriction (Alt-RAMEC) protocol on patients with unilateral cleft lip and palate (UCLP) along with maxillary protraction using cone beam computed tomography (CBCT) records and a finite element modeling (FEM) model.

MATERIALS AND METHODS

Twenty-five patients (aged 9-13 years) with UCLP having a GOSLON score 3 were selected for this prospective single-arm cohort study after obtaining necessary informed consent. A 9-week Alt-RAMEC protocol using a custom-made fan-shaped expansion screw was initiated, which was followed by 6-month facemask wear. Pre (T1) and posttreatment (T2) records including CBCT were taken and were evaluated for treatment changes in all 3 dimensions using paired t test. Additionally, a FEM model (ANSYS 15.0) using the Alt-RAMEC protocol was also analyzed for the displacement and stress on various craniofacial structures.

RESULTS

Significant forward movement of the maxilla along with clockwise rotation of mandible along with statistically significant increase in lower molar height and upper incisor proclination (P < .05) was observed. CBCT evaluation showed a statistical significant decrease in buccal alveolar bone thickness and increase in molar inclination (P < .05). Finite element modeling analysis highlighted that the maximum displacement occurred at the anterior region with stresses radiating till the anterior nasal spine, zygomatic arch, and sphenoid bone.

CONCLUSION

Alt- RAMEC protocol combined with facemask protraction can lead to significant maxillary advancement, with some transient decrease in buccal bone thickness noted thereby warranting long-term studies to further assess its effect on the dentofacial apparatus.

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.

Effect of Photobiomodulation on Relapse in an Experimental Rapid Maxillary Expansion Model in Rat

Rapid maxillary expansion (RME) is performed on transversely deficient maxilla. As all orthodontic treatments, retention is important in maintaining therapeutic outcomes. Fixed /removable retainers are used post-RME causing hygiene and compliance problems. Given photobiomodulation's positive effects on the quantity and quality of bone regeneration, its effect on post-RME relapse was studied. Thirty Sprague Dawley rats were randomly divided into group R, non-irradiated RME-treated (n = 12), group P, irradiated RME-treated (n = 12) and group C, non-RME non-irradiated (n = 6). A 1.5 mm metal ring inserted between maxillary incisors at days 0 and 15 was expanded until 1.5 mm space was obtained at day 30. In group P, Ga-Al-As diode laser (810 nm, 100 mW, 4J/cm² , 30 secs) was applied on days 0, 2, 4, 6, 8, 10, 12 and 14 as predictor variable. The relapse was measured as the space lost between incisors for 30 days after appliance removal (primary outcome variable) and compared with t-test. In week 2, space loss in group P was significantly lower (P < 0.05) than all other groups. The relapse during weeks 2 and 3 was significantly lower in group P than group R. However, no significant difference in relapse amount was found between groups during first and fourth week. There was a significant difference (P < 0.05) between groups in relapse rates (secondary outcome variable) but not in total relapse after 4 weeks. Photobiomodulation proved beneficial in resisting relapse in our study, and it is suggested to be continued until the end of expansion.

Buccal Bone Changes Around First Permanent Molars and Second Primary Molars after Maxillary Expansion with a Low Compliance Ni-Ti Leaf Spring Expander

Background: Vestibular bone thickness changes and dento-alveolar buccal tipping of second primary molars and of first molars after maxillary expansion performed with a slow maxillary expansion protocol was investigated. Methods: Twenty patients (mean age 7.3 ± 0.9 years old; 9 male and 11 female) were treated according to the Leaf Expander protocol. Buccal alveolar bone thickness (BT), buccal alveolar bone height (BH), inter-dental angle (TIP), and inter-molar width (IW) regarding first molars and second primary molars were calculated before and after expansion on cone beam computed tomography (CBCT) images. Descriptive statistics and paired t-tests were used to assess changes between the pre-treatment and post-treatment measurements. Results: Bone thickness vestibular to second primary molars and intermolar width of both teeth were the only variables that showed statistically significant changes. Conclusions: It appears that buccal bone thickness vestibular to first molars was not significantly reduced after maxillary expansion with the Leaf Expander. The clinical use of a slow maxillary expander with Ni-Ti springs appears efficient and safe in in the correction of maxillary hypoplasia during mixed dentition.

Comparison of Skeletal and Dental Changes Obtained from a Tooth-Borne Maxillary Expansion Appliance Compared to the Damon System Assessed through a Digital Volumetric Imaging: A Randomized Clinical Trial

The purpose of this study was to evaluate and compare dental and skeletal changes associated with the Damon and Rapid Maxillary Expander (RME) expansion using Cone-Beam Computed Tomography (CBCT). Eighty-two patients, from The University of Alberta Orthodontic Clinic, were randomly allocated to either Group A or B. Patients in Group A received orthodontic treatment using the Damon brackets. Patients in Group B received treatment using the Hyrax (a type of RME) appliance. CBCT images were taken two times (baseline and after expansion). The AVIZO software was used to locate 18 landmarks (dental and skeletal) on sagittal, axial, and coronal slices of CBCT images. Comparison between two groups showed that transverse movement of maxillary first molars and premolars was much greater in the Hyrax group. The lateral movements of posterior teeth were associated with buccal tipping of crowns. No clinically significant difference in the vertical or anteroposterior direction between the two groups was noted. Alveolar bone next to root apex of maxillary first premolar and molar teeth showed clinically significant lateral movement in the Hyrax group only. The comparison between two groups showed significantly greater transverse expansion of the first molar and first premolars with buccal tipping in the RME group.

Short-term treatment effects produced by rapid maxillary expansion evaluated with computed tomography: A systematic review with meta-analysis

OBJECTIVE

To identify the available evidence on the effects of rapid maxillary expansion (RME) with three-dimensional imaging and provide meta-analytic data from studies assessing the outcomes using computed tomography.

METHODS

Eleven electronic databases were searched, and prospective case series were selected. Two authors screened all titles and abstracts and assessed full texts of the remaining articles. Seventeen case series were included in the quantitative synthesis. Seven outcomes were investigated: nasal cavity width, maxillary basal bone width, alveolar buccal crest width, alveolar palatal crest width, inter-molar crown width, inter-molar root apex width, and buccopalatal molar inclination. The outcomes were investigated at two-time points: postexpansion (2-6 weeks) and post-retention (4-8 months). Mean differences and 95% confidence intervals were used to summarize and combine the data.

RESULTS

All the investigated outcomes showed significant differences postexpansion (maxillary basal bone width, +2.46 mm; nasal cavity width, +1.95 mm; alveolar buccal crest width, +3.90 mm; alveolar palatal crest width, +3.09 mm; intermolar crown width, +5.69 mm; inter-molar root apex width, +2.85 mm; and dental tipping, +3.75°) and post-retention (maxillary basal bone width, +2.21 mm; nasal cavity width, +1.55 mm; alveolar buccal crest width, +3.57 mm; alveolar palatal crest width, +3.32 mm; inter-molar crown width, +5.43 mm; inter-molar root apex width, +4.75 mm; and dental tipping, 2.22°) compared to pre-expansion.

CONCLUSIONS

After RME, skeletal expansion of the nasomaxillary complex was greater in most caudal structures. Maxillary basal bone showed 10% post-retention relapse. During retention period, uprighting of maxillary molars occurred.

Differential assessment of skeletal, alveolar, and dental components induced by microimplant-supported midfacial skeletal expander (MSE), utilizing novel angular measurements from the fulcrum

Background

In order to assess skeletal expansion, alveolar bone bending, and dental tipping after maxillary expansion, linear and angular measurements have been performed utilizing different craniofacial references. Since the expansion with midfacial skeletal expander (MSE) is archial in nature, the aim of this paper is to quantify the differential components of MSE expansion by calculating the fulcrum locations and applying a novel angular measurement system.

Methods

Thirty-nine subjects with a mean age of 18.2 ± 4.2 years were treated with MSE. Pre- and post-expansion CBCT records were superimposed and compared. The rotational fulcrum of the zygomaticomaxillary complex was identified by localizing the interfrontal distance and modified interfrontal distance. Based on the fulcrum, a novel angular measurement method is presented and compared with a conventional linear method to assess changes of the zygomaticomaxillary complex, dentoalveolar bone, and maxillary first molars.

Results

From 39 patients, 20 subjects have the rotational fulcrum of the zygomaticomaxillary complex at the most distant points of the interfrontal distance (101.6 ± 4.7 mm) and 19 subjects at the most distant points of the modified interfrontal distance (98.9 ± 5.7 mm). Linear measurements accounted for 60.16% and 56.83% of skeletal expansion, 16.15% and 16.55% of alveolar bone bending, and 23.69% and 26.62% of dental tipping for right and left side. Angular measurements showed 96.58% and 95.44% of skeletal expansion, 0.34% and 0.33% alveolar bone bending, and 3.08% and 4.23% of dental tipping for the right and left sides. The frontozygomatic, frontoalveolar, and frontodental angles were not significant different (P > 0.05).

Conclusions

In the coronal plane, the center of rotation for the zygomaticomaxillary complex was located at the most external and inferior point of the zygomatic process of the frontal bone or slightly above and parallel to the interfrontal distance. Due to the rotational displacement of the zygomaticomaxillary complex, angular measurements should be a preferred method for assessing the expansion effects, instead of the traditional linear measurement method.

Three-dimensional assessment of transverse dentoskeletal mandibular dimensions after utilizing two designs of fixed mandibular expansion appliance: A prospective clinical investigation

The aim of this clinical study was to evaluate and compare the dentoskeletal transverse mandibular arch dimensions following the use of two designs of fixed mandibular expanders using cone beam computed tomography (CBCT). Twenty orthodontic patients, 12 females and 8 males, with mean age of 13.4 ± 0.5 years were selected and randomly divided into two equivalent groups; group A consisted of 10 patients (4 boys, 6 girls) who were treated with modified Williams expander and group B consisted of 10 patients (4 boys, 6 girls) who were treated with a two-arm fixed expander. Consistent expansion instructions were given to all patients according to a standardized slow protocol of one quarter turn twice/week for both expanders. Routine orthodontic records as well as mandibular CBCTs were obtained before (T1) and immediately after expansion (T2) to estimate changes in dentoskeletal mandibular transverse dimensions. The data was statistically analyzed and the significance level was set at p ≤ 0.05. Mandibular intercanine, inter-premolar, intermolar widths; and arch perimeter were significantly increased (p ≤ 0.05) following expansion with both fixed expanders. However, the changes in inter-premolar width, intercanine width, and arch perimeter were significantly augmented in two-arm fixed expander group than modified Williams’s group. In contrast, their effects on the skeletal mandibular body width were non-significant (p > 0.05). Both expanders yielded significant and equivalent dentoalveolar effects that were more evident with two-arm fixed expander than the William one. Both fixed designs enhanced mandibular transverse dental dimensions; however, they were unsuccessful to create any considerable skeletal effects.

Evaluation of palate area before and after rapid maxillary expansion, using cone-beam computed tomography

Objective:

The aim of this study was to estimate the changes in the palate area after rapid maxillary expansion (RME) with the Hyrax expander in growing subjects, using cone beam computed tomography (CBCT).

Methods:

Fourteen patients (9 girls and 5 boys; mean age = 11.7 ± 2.4 years) who required RME as part of their orthodontic treatment were included in this study. CBCT records had been taken before RME treatment (T₀), at the end of active expansion (T₁) and after a 6-month retention period (T₂). The CBCT scans were manipulated with Dolphin Imaging^® version 11.7 Premium software, in which landmarks were positioned and measured in relation to sagittal, coronal and axial planes, to verify the palate surface area. In addition, linear measurements of the palatal depth and width were assessed. These measurements were compared by using analysis of variance (ANOVA) for repeated measures. A p-value smaller than 0.05 was considered statistically significant.

Results:

The palatal surface area and width significantly increased from T₀ to T₁, respectively by 9.27% and 9.71%, and both decreased in a non-significant manner from T₁ to T₂. The palatal depth had non-significant differences at T₀, T₁ and T₂.

Conclusions:

RME promotes a significant gain in the surface area of the palate and an increase in intermolar width. The Hyrax appliance was effective for the treatment of maxillary atresia in growing patients. There was no vertical alteration of the palate. After a 6-month retention period, the maxilla transverse dimension and the surface area of the palate remained stable.

Dental and skeletal changes associated with the Damon system philosophical approach

OBJECTIVE

To compare the skeletal and dentoalveolar changes produced by the Damon system's treatment philosophy to traditional orthodontic treatment techniques.

MATERIALS AND METHODS

An electronic search in four major databases was completed: Cochrane, PubMed, EMBASE, and Google Beta Scholar on October 5th, 2018. Randomized controlled trials, prospective and retrospective controlled clinical trials were included in this systematic review. The quality assessment of individual studies was done using two different tools: The Cochrane Risk of Bias Assessment Tool (RTCs) and The Methodological Index for Non-Randomized Studies (MINORS) (non-RCTs).

RESULTS

Seven studies were included for this qualitative analysis. Six studies compared the Damon system to various types of conventional (non self-ligating bracket) system as a comparison group. One study used a quad helix as a comparison for a few months before a full bonding appointment with conventional brackets. The majority of studies found an increase in maxillary inter-canine, inter-premolar, and intermolar distance after the treatment in both the Damon and comparison groups. Yet, all studies concluded that there is no significant difference in the final transverse dimension between the two groups. One study also found that the transverse expansion was achieved mainly by tipping movement of posterior dentition, and a decrease in the posterior buccal bone area was evident in both groups after treatment.

CONCLUSION

There is not enough evidence to support the claim that the Damon system allows additional arch expansion with better tipping control than with traditional techniques.

Molar inclination and surrounding alveolar bone change relative to the design of bone-borne maxillary expanders: A CBCT study

OBJECTIVE

To evaluate the molar inclination and skeletal and alveolar bone changes when comparing tooth bone-borne (MSE) and tissue bone-borne type maxillary expanders (C-expander) using cone-beam computed tomography (CBCT) in late adolescence.

MATERIALS AND METHODS

A sample of 48 late-adolescent patients were divided into two groups according to the type of expander: MSE group (n = 24, age = 19.2 ± 5.9 years) and C-expander group (n = 24, age = 18.1 ± 4.5 years). CBCT scans were taken before treatment and 3 months after expansion. Transverse skeletal and dental expansion, alveolar inclination, tooth axis, buccal alveolar bone height, thickness, dehiscence, and fenestration were evaluated on the maxillary first molar. Paired t-test, independent t-test, Pearson's chi-square test, and Spearman correlation analysis were performed.

RESULTS

The MSE group produced greater dental expansion (P < .05), whereas skeletal expansion was similar in both groups (P = .859). The C expander group had more alveolar bone inclination change (P < .01), and the MSE group had more buccal tipping of the anchorage teeth (P < .01 or .001). Buccal alveolar bone height loss and thickness changes were greater in the MSE group (P < .01 or <.001). Formation of dehiscences was more frequent in the MSE group (P < .001), whereas for fenestrations, there were no significant differences between the two groups. Buccal bone height loss in the MSE group had a negative correlation with initial buccal bone thickness.

CONCLUSIONS

The incorporation of teeth into bone-borne expanders resulted in an increase in the severity of side effects. For patients in late adolescence, tissue bone-borne expanders offer comparable skeletal effects to tooth bone-borne expanders, with fewer dentoalveolar side effects.

Levels of Cytokines in Gingival Crevicular Fluid during Rapid Maxillary Expansion and the Subsequent Retention Period

OBJECTIVE

To monitor the effects of rapid maxillary expansion (RME) on bone metabolic activities during and after 3 months of retention.

STUDY DESIGN

Fifteen patients with a mean age of 12.9 ± 0.6 years were treated with a bonded expansion device, activated 2 turns per day. The retention period was 3 months. Clinical periodontal parameters were recorded at baseline and after retention. Gingival crevicular fluid (GCF) samples were collected from maxillary first molars from the compression sides at baseline, then at 1 and 10 days and after retention. Tension side samples were obtained at baseline and after retention. Interleukin-1beta (IL-1β), transforming growth factor beta1 (TGF-β1), prostaglandin E₂ (PGE₂) and nitric oxide (NO) levels were specifically measured.

RESULTS

Periodontal parameters increased significantly after retention relative to baseline values. Levels of IL-1β, TGF-β1 and PGE₂ increased on day 10, and decreased after retention on the compression side. NO levels were elevated on day 10, and remained higher after retention on the compression side. Tension side cytokine levels remained higher relative to baseline values after retention.

CONCLUSIONS

The results of this study indicate the importance of ongoing adaptive bone activities after 3 months of retention with RME, which should be considered questionable as an effective retention period.

Efficacy of injectable platelet-rich plasma in reducing alveolar bone resorption following rapid maxillary expansion: A cone-beam computed tomography assessment in a randomized split-mouth controlled trial

OBJECTIVES

To evaluate the effectiveness of platelet-rich plasma (PRP) with its growth factors in minimizing the side effects of rapid maxillary expansion (RME) on the periodontal tissue of anchoring teeth using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

A randomized, split-mouth clinical trial was conducted on 18 patients aged 12-16 years (14 ± 1.65) with a skeletal maxillary constriction who underwent RME using a Hyrax appliance. The sample was randomly divided into two groups: intervention and control sides. PRP was prepared and injected on the buccal aspect of supporting teeth in the intervention group. High-resolution CBCT imaging (H-CBCT) was carried out preoperatively (T0) and after 3 months of retention (T1) to study the buccal bone plate thickness (BBPT) and buccal bone crest level (BBCL) of anchoring teeth. Changes induced by expansion were evaluated using paired sample t-test (P < .05).

RESULTS

Results showed that there was no significant difference in BBPT and BBCL between the two groups after RME (P > .05). The prevalence of dehiscence and fenestrations was increased at (T1) in both groups and the percentage was higher in the PRP group.

CONCLUSIONS

RME induced vertical and horizontal bone loss. PRP did not minimize alveolar defects after RME.

Nasal soft- and hard-tissue changes following tooth-borne and hybrid surgically assisted rapid maxillary expansion: A randomized clinical cone-beam computed tomography study

PURPOSE

The aim of this study was to assess the effects of tooth/bone-borne (hybrid) and tooth-borne (TB) surgically assisted rapid maxillary expansion (SARME) on the width of the nasal soft and hard tissue.

PATIENTS AND METHODS

Twenty skeletally mature patients (nine males and 11 females; mean age 19.4 years) with transverse maxillary hypoplasia were randomly assigned to hybrid or TB devices. The patients had undergone SARME operations, performed by the same surgical team using the same procedure (Le Fort I osteotomy with pterygomaxillary dysjunction, midline osteotomy, and no down-fracture). Nasal soft- and hard-tissue changes were analyzed using CBCT preoperatively (T0), at the end of the active expansion phase (T1), and after 6 months of retention (T2). The study was approved by the relevant ethics committee.

RESULTS

The skeletal and soft-tissue nasal parameters increased significantly in the T0-T1 and T0-T2 periods in both groups (P < 0.05). No statistically significant differences between the groups were observed. The mean piriform aperture width increased from 1.26 mm in T0-T1 to 0.97 mm in T1-T2 and 2.17 mm in T0-T2 (P < 0.008). In the soft tissue, the alar base width increased to 2.78 mm and the alar width to 2.95 mm in T0-T2 (P = 0.001). There was a positive correlation (63.6%) between the changes in skeletal and soft-tissue values.

CONCLUSION

The hybrid and TB devices led to similarly significant widening effects in nasal soft and hard tissues in both the short term and 6 months after SARME.

United Reference Method for three-dimensional treatment evaluation

Background

Reproducible and descriptive Three-dimensional treatment evaluation can enhance future treatment based on realistic results. So, the purpose of this study was to describe a new method for three-dimensional treatment evaluation showing how to use fully-automated craniofacial superimposition of CBCT records combined with reference system to obtain descriptive and comparable results. This new method was named United Reference Method (URM).

Methods

URM is a combination of automated 3D superimposition on anterior cranial base surface anatomy and measurements based on reference system. It was developed to show how to use fully-automated superimposition to obtain descriptive numerical comparable values. The method is based on: one main reference system for both superimposed CBCT records, semi-automation to increase accuracy, all measurements are projections and auxiliary references to aid in landmarks identification and measurements.

The method steps can be described following a four-step approach: (1) Superimposition performed through a fully automated, voxel-wise, rigid registration considering only cranial base as a stable structure; (2) Identification of reference landmarks once on the superimposed records for corrected Frankfort Horizontal plane (C-FH) construction and a new semi-automated constructed Sella point to correct Orbital asymmetry; (3) Head orientation of superimposed CBCT images based on the C-FH; (4) Identification of landmarks affected by treatment with the aid of auxiliary reference planes. Evaluation of linear or angular changes derived by projection of same pre- and post-treatment landmarks on the C-FH. Pre- and post-expansion CBCT scans of 20 unilateral cleft lip and palate patients were used to calculate intra and inter-rater reliability. (X, Y and Z) coordinates, mean, standard deviation (SD) and Intra-class Correlation Coefficient (ICC) were calculated.

Results

The proposed coordinates for C-FH construction showed ICC ≥ 0.998 and SD ranging from 0.064 to 0.242 mm. On the other hand, excluded coordinates due to expected natural craniofacial asymmetry had the lowest reliability ICC ≥0.742 and SD dramatically increased up to 1.112 mm.

Conclusion

URM showed adequate reliability so it can be used to produce three-dimensional descriptive data of craniofacial structural changes.

The immediate effect of alternate rapid maxillary expansions and constrictions on the alveolus: a retrospective cone beam computed tomography study

Background

Rapid maxillary expansion reduced the expander’s anchor teeth buccal alveolar bone thickness. However, the effects of alternate rapid maxillary expansions and constrictions (Alt-RAMEC) on the expander’s anchor teeth alveolar thickness has not been assessed. The purpose of this retrospective study was to evaluate the effects of Alt-RAMEC on the alveolus surrounding the anchor teeth of a double-hinged expander.

Methods

Twenty-six individuals, including 12 males (11.5 ± 1.00 years) and 14 females (11.5 ± 0.90 years), who had double-hinged expander for 7 weeks of Alt-RAMEC and then 3 months of maxillary protraction, were included. Their cone beam computed tomography (CBCT) images taken 3–6 months before treatment (T0) and after 7 week of Alt-RAMEC (T1), were studied for the buccal alveolar bone thickness (BABT) and palatal alveolar bone thickness (PABT) of the expander’s anchor teeth (first molars and first and second premolars) in four axial sections. The intra-class correlation coefficient, Dahlberg’s formula, and paired t tests were used to analyze the method errors, and the intra-group changes of the BABT and PABT at T0-T1 were analyzed by paired t test (p < 0.05).

Results

The 7 weeks of Alt-RAMEC significantly reduced the BABT of the expander’s anterior anchor teeth (0.54~ 70 mm, p < 0.05) and at the cervical region (0.14~ 0.25 mm, p < 0.05), but not at the apical region of the expander’s posterior anchor teeth. The reduction of BABT by 7 weeks of Alt-RAMEC was within the scope of the initial BABT. On the opposite, the Alt-RAMEC significantly (p < 0.05) increased the PABT in the anterior anchor teeth and the cervical region of posterior anchor teeth.

Conclusions

A 7-week protocol of Alt-RAMEC with double-hinged expander for maxillary protraction might reduce the buccal alveolar bone thickness of the expander’s anchor teeth, although the reduction is within the scope of initial alveolar thickness of the expander’s anchor teeth.

Assessing the validity of ITK-SNAP software package in measuring the volume of upper airway spaces secondary to rapid maxillary expansion

INTRODUCTION:

The purpose of this study is to evaluate the validity of a free-access software package (ITK-SNAP) in segmenting and measuring the volume of upper airway spaces secondary to rapid maxillary expansion (RME).

MATERIALS AND METHODS:

Sixteen participants who required RME were recruited for this study. Preoperative (T1) and 6-month postoperative (T2) cone-beam computed tomographic scans of all participants were analyzed. OnDemand3D software packages was used for superimposition and orientation of the images, while ITK-SNAP software was used to measure the volume of airway spaces. At week one (W1), all volumetric measurements were carried out by one examiner and repeated after 1 week (W2). Paired t-test, the interclass correlation coefficient, and Dahlberg coefficients of reliability were used to assess the reproducibility.

RESULTS:

Student's t-test showed no significant difference between the W1 and W2 set of measurements (P > 0.05). Coefficients of reliability were above 95% and intraclass correlation coefficient ranged from 0.99 to 1.000, which altogether confirmed the satisfactory reproducibility of the measurements.

CONCLUSIONS:

ITK-SNAP software package is a reliable and cost-effective method to segment and measure upper airway changes subsequent to RME.

Effects of rapid maxillary expansion in cleft patients resulting from the use of two different expanders

Objective:

The aim of this study was to evaluate the skeletal and dental effects of rapid maxillary expansion (RME) in cleft patients using two types of expanders.

Methods:

Twenty unilateral cleft lip and palate patients were randomly divided into two groups, according to the type of expander used: (I) modified Hyrax and (II) inverted Mini-Hyrax. A pretreatment cone-beam computed tomographic image (T0) was taken as part of the initial orthodontic records and three months after RME, for bone graft planning (T1).

Results:

In general, there was no significant difference among groups (p > 0.05). Both showed a significant transverse maxillary expansion (p < 0.05) and no significant forward and/or downward movement of the maxilla (p > 0.05). There was greater dental crown than apical expansion. Maxillary posterior expansion tended to be larger than anterior opening (p < 0.05). Cleft and non-cleft sides were symmetrically expanded and there was no difference in dental tipping between both sides (p > 0.05).

Conclusions:

The appliances tested are effective in the transverse expansion of the maxilla. However, these appliances should be better indicated to cleft cases also presenting posterior transverse discrepancy, since there was greater expansion in the posterior maxillary region than in the anterior one.

Novel methodologies and technologies to assess mid-palatal suture maturation: a systematic review

INTRODUCTION

A reliable method to assess midpalatal suture maturation to drive clinical decision-making, towards non-surgical or surgical expansion, in adolescent and young adult patients is needed. The objectives were to systematically review and evaluate what is known regarding contemporary methodologies capable of assessing midpalatal suture maturation in humans.

METHODS

A computerized database search was conducted using Medline, PubMed, Embase and Scopus to search the literature up until October 5, 2016. A supplemental hand search was completed of references from retrieved articles that met the final inclusion criteria.

RESULTS

Twenty-nine abstracts met the initial inclusion criteria. Following assessment of full articles, only five met the final inclusion criteria. The number of subjects involved and quality of studies varied, ranging from an in-vitro study using autopsy material to prospective studies with in vivo human patients. Three types of evaluations were identified: quantitative, semi-quantitative and qualitative evaluations. Four of the five studies utilized computed tomography (CT), while the remaining study utilized non-invasive ultrasonography (US). No methodology was validated against a histological-based reference standard.

CONCLUSIONS

Weak limited evidence exists to support the newest technologies and proposed methodologies to assess midpalatal suture maturation. Due to the lack of reference standard validation, it is advised that clinicians still use a multitude of diagnostic criteria to subjectively assess palatal suture maturation and drive clinical decision-making.

Slow versus rapid maxillary expansion in bilateral cleft lip and palate: a CBCT randomized clinical trial

OBJECTIVES

The purpose of this "two-arm parallel" trial was to compare the orthopedic, dental, and alveolar bone plate changes of slow (SME) and rapid (RME) maxillary expansions in patients with complete bilateral cleft lip and palate (BCLP).

MATERIAL AND METHODS

Forty-six patients with BCLP and maxillary arch constriction in the late mixed dentition were randomly and equally allocated into two groups. Computer-generated randomization was used. Allocation was concealed with sequentially, numbered, sealed, opaque envelopes. The SME and RME groups comprised patients treated with quad-helix and Haas/Hyrax-type expanders, respectively. Cone-beam computed tomography (CBCT) exams were performed before expansion and 4 to 6 months post-expansion. Nasal cavity width, maxillary width, alveolar crest width, arch width, palatal cleft width, inclination of posterior teeth, alveolar crest level, and buccal and lingual bone plate thickness were assessed. Blinding was applicable for outcome assessment only. Interphase and intergroup comparisons were performed using paired t tests and t tests, respectively (p < 0.05).

RESULTS

SME and RME similarly promoted significant increase in all the maxillary transverse dimensions at molar and premolar regions with a decreasing expanding effect from the dental arch to the nasal cavity. Palatal cleft width had a significant increase in both groups. Significant buccal inclination of posterior teeth was only observed for RME. Additionally, both expansion procedures promoted a slight reduction of the alveolar crest level and the buccal bone plate thickness.

CONCLUSIONS

No difference was found between the orthopedic, dental, and alveolar bone plate changes of SME and RME in children with BCLP. Both appliances produced significant skeletal transverse gains with negligible periodontal bone changes. Treatment time for SME, however, was longer than the observed for RME.

CLINICAL RELEVANCE

SME and RME can be similarly indicated to correct maxillary arch constriction in patients with BCLP in the mixed dentition.

Three-Dimensional Force Measurements During Rapid Palatal Expansion in Sus scrofa

Rapid palatal expansion is an orthodontic procedure widely used to correct the maxillary arch. However, its outcome is significantly influenced by factors that show a high degree of variability amongst patients. The traditional treatment methodology is based on an intuitive and heuristic treatment approach because the forces applied in the three dimensions are indeterminate. To enable optimal and individualized treatment, it is essential to measure the three-dimensional (3D) forces and displacements created by the expander. This paper proposes a method for performing these 3D measurements using a single embedded strain sensor, combining experimental measurements of strain in the palatal expander with 3D finite element analysis (FEA). The method is demonstrated using the maxillary jaw from a freshly euthanized pig (Sus scrofa) and a hyrax-design rapid palatal expander (RPE) appliance with integrated strain gage. The strain gage measurements are recorded using a computer interface, following which the expansion forces and extent of expansion are estimated by FEA. A total activation of 2.0 mm results in peak total force of about 100 N-almost entirely along the direction of expansion. The results also indicate that more than 85% of the input activation is immediately transferred to the palate and/or teeth. These studies demonstrate a method for assessing and individualizing expansion magnitudes and forces during orthopedic expansion of the maxilla. This provides the basis for further development of smart orthodontic appliances that provide real-time readouts of forces and movements, which will allow personalized, optimal treatment.

Comparison of tooth-borne and hybrid devices in surgically assisted rapid maxillary expansion: A randomized clinical cone-beam computed tomography study

PURPOSE

The objective of this 2-arm, parallel, single-center trial was to compare the skeletal, dental, and periodontal effects of tooth-borne (TB) and hybrid devices in surgically assisted rapid maxillary expansion (SARME).

MATERIALS AND METHODS

Twenty consecutive patients (9 male and 11 female) with skeletal transverse maxillary deficiency seeking treatment at the Department of Orthodontics at Istanbul University in Istanbul, Turkey, were randomly assigned to 2 groups (10 patients each). Hybrid devices were inserted in the first group and TB (Hyrax) devices in the second. All of the patients had undergone SARME operations, which were carried out by the same surgeons using the same procedure (a Le Fort I osteotomy with pterygomaxillary dysjunction). All of the patients had similar transverse deficits, and 7 mm of expansion was achieved in all of them over 14 days. CBCT was carried out preoperatively (T0), at the end of the active expansion phase (T1), and after 6 months of retention (T2). Measurements were made using Mimics 16.0.

RESULTS

Anterior skeletal maxillary widening parameters increased significantly in the T0-T1 and T0-T2 periods in the 2 groups (P = 0.001). There was significantly less dental expansion anteriorly with the hybrid devices (T0-T2: 4.03 mm vs. 6.29 mm). The first molars tipped buccally more in the group with TB devices during the T0-T1 phase (P = 0.029) and moved upright more than those in the group with hybrid devices during the retention phase (P = 0.035). Dental tipping, buccal alveolar bone resorption, and root resorption were observed significantly more often with the TB devices.

CONCLUSION

Hybrid RME devices, with similar skeletal effects, different dental movement patterns, and fewer dental and periodontal side effects, thus appear to be a beneficial alternative to TB devices for SARME procedures.

Gingival crevicular fluid alkaline phosphate activity during the retention phase of maxillary expansion in prepubertal subjects: A split-mouth longitudinal study

INTRODUCTION

The aim of this study was to monitor the alveolar bone formation at the tension sites of teeth supporting the appliances for rapid maxillary expansion (RME) during the retention phase according to the local gingival crevicular fluid (GCF) alkaline phosphatase (ALP) activity.

METHODS

This split-mouth prospective study included 23 prepubertal subjects (15 girls, 8 boys; mean age, 9.0 ± 1.4 years) who had a constricted maxillary arch and were undergoing RME. Periodontal parameters, including probing depth, were recorded at 3 and 6 months after RME. Furthermore, the GCF ALP activity was measured at the tension sites of the supporting test teeth (TT) and at the antagonist control teeth (CT) sites.

RESULTS

Periodontal parameters were generally similar between the TT and CT sites during the study, with the exception that probing depth underwent a slight increase at the TT sites. At baseline, the GCF ALP activity was similar between the TT and CT sites; however, at both 3 and 6 months, significantly greater enzymatic activity was seen at the TT sites. The overall probing depth changes were not significantly correlated with the corresponding GCF ALP activity changes for either the TT or the CT sites.

CONCLUSIONS

Alveolar bone formation at the tension sites would last up to 6 months of retention after RME. These results warrant more comprehensive studies to assess whether the GCF ALP activity has potential as a diagnostic tool for bone formation during the retention phase of RME.

Periodontal, dentoalveolar, and skeletal effects of tooth-borne and tooth-bone-borne expansion appliances

INTRODUCTION

The purposes of this study were to evaluate and compare the periodontal, dentoalveolar, and skeletal effects of tooth-borne and tooth-bone-borne expansion devices using cone-beam computed tomography.

METHODS

Twenty-five patients requiring maxillary expansion were randomly allocated into 2 groups. A tooth-borne hyrax appliance was used in the first group, consisting of 13 patients (8 girls, 5 boys; mean age, 14.3 ± 2.3 years), and a tooth-bone-borne hybrid hyrax appliance was used in the second group of 12 patients (6 girls, 6 boys; mean age, 13.8 ± 2.2 years). Cone-beam computed tomography records were taken before and 3 months after expansion, and periodontal, dentoalveolar, and skeletal measurements were made on the cone-beam computed tomography images with a software program. The 2 independent-samples t test and the Mann-Whitney U test were used to evaluate treatment changes for both groups. Paired-samples t test and Wilcoxon test were used to compare the measurements at 2 time points for variables.

RESULTS

Significant skeletal changes and increases in interdental distances were observed in both groups. However, the distances between the first and second premolars increased more with the hyrax appliance (7.5 ± 4.2 and 7.9 ± 3.3 mm, respectively) than with the hybrid hyrax (3.2 ± 2.6 and 4.5 ± 3.8 mm, respectively) (P <0.05). Similar reductions in buccal bone plate thickness and increases in palatal bone plate thickness of the anchored teeth occurred in both groups, whereas changes in buccal and palatal bone thicknesses of the left first premolars significantly differed between groups (P <0.001). No significant intergroup difference was found in terms of absolute dental tipping.

CONCLUSIONS

Both tooth-borne and tooth-bone-borne rapid expansion are effective methods for treating a narrow maxilla. However, the hyrax appliance resulted in greater expansion in the premolar region. On the other hand, the hybrid hyrax appliance did not cause changes in the bony support of the first premolars.

Alveolar bone changes after asymmetric rapid maxillary expansion

OBJECTIVE

To quantitatively evaluate the effects of asymmetric rapid maxillary expansion (ARME) on cortical bone thickness and buccal alveolar bone height (BABH), and to determine the formation of dehiscence and fenestration in the alveolar bone surrounding the posterior teeth, using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

The CBCT records of 23 patients with true unilateral posterior skeletal crossbite (10 boys, 14.06 ± 1.08 years old, and 13 girls, 13.64 ± 1.32 years old) who had undergone ARME were selected from our clinic archives. The bonded acrylic ARME appliance, including an occlusal stopper, was used on all patients. CBCT records had been taken before ARME (T1) and after the 3-month retention period (T2). Axial slices of the CBCT images at 3 vertical levels were used to evaluate the buccal and palatal aspects of the canines, first and second premolars, and first molars. Paired samples and independent sample t-tests were used for statistical comparison.

RESULTS

The results suggest that buccal cortical bone thickness of the affected side was significantly more affected by the expansion than was the unaffected side (P < .05). ARME significantly reduced the BABH of the canines (P < .01) and the first and second premolars (P < .05) on the affected side. ARME also increased the incidence of dehiscence and fenestration on the affected side.

CONCLUSIONS

ARME may quantitatively decrease buccal cortical bone thickness and height on the affected side.

Immediate periodontal bone plate changes induced by rapid maxillary expansion in the early mixed dentition: CT findings

OBJECTIVE

This study aimed at evaluating buccal and lingual bone plate changes caused by rapid maxillary expansion (RME) in the mixed dentition by means of computed tomography (CT).

METHODS

The sample comprised spiral CT exams taken from 22 mixed dentition patients from 6 to 9 years of age (mean age of 8.1 years) presenting constricted maxillary arch treated with Haas-type expanders. Patients were submitted to spiral CT scan before expansion and after the screw activation period with a 30-day interval between T1 and T2. Multiplanar reconstruction was used to measure buccal and lingual bone plate thickness and buccal bone crest level of maxillary posterior deciduous and permanent teeth. Changes induced by expansion were evaluated using paired t test (p < 0.05).

RESULTS

Thickness of buccal and lingual bone plates of posterior teeth remained unchanged during the expansion period, except for deciduous second molars, which showed a slight reduction in bone thickness at the distal region of its buccal aspect. Buccal bone dehiscences were not observed in the supporting teeth after expansion.

CONCLUSIONS

RME performed in mixed dentition did not produce immediate undesirable effects on periodontal bone tissues.