Transverse Skeletal Effects of Rapid Maxillary Expansion in Pre and Post Pubertal Subjects: A Systematic Review

Analysis of changes and correlation in condyle-fossa relationship after maxillary skeletal expansion

OBJECTIVE

To investigate the changes in condyle-glenoid fossa relationship after maxillary skeletal expansion (MSE) and to verify the correlation between the condyle positional changes and expansion effect.

METHODS

In this study, 20 patients (mean age 21.1 ± 5.7 years, 8 male, 12 female) with maxillary transverse deficiency (MTD) were treated with the MSE appliance, which contained molar bands and a expander with four micro-implants. The CBCT images were taken before expansion (T0), after expansion (T1) and after 6 months of maintenance (T2). The posterior TMJ space (PS), superior TMJ space (SS), anterior TMJ space, coronal lateral TMJ space (CLS), coronal medial TMJ space (CMS), condyle axis angle, maxillary basal bone width (BWM), inter-molars width, nasal bone width, molar inclination and molar palatal cusp height (U6H) were measured using Dolphin Imaging.

RESULTS

At T1, compared with T0, the PS and SS significantly increased by 0.41 mm (P = .008) and 0.3 mm (P = .007). But only the SS significantly increased by 0.21 mm (P = .025) at T2. There was a significant difference of 0.37 mm (left-right, P = .014) between the left and right SS at T0, but no significant difference at T1 and T2. The increased BMW showed weak positive correlations with the change of PS (P = .015) and CMS (P = .031), and the decreased U6H showed weak negative correlations with the change of PS (P = .015) and CLS (P = .031) at T1.

CONCLUSIONS

The use of MSE led to an increase in the SS and PS, which were weakly correlated with BWM and U6H. But this effect in the TMJ space gradually diminished after 6 months of maintenance, and the symmetry of the condyle-fossa relationship was preserved.

Treatment effects after maxillary expansion using invisalign first system vs. acrylic splint expander in mixed dentition: a prospective cohort study

BACKGROUND

Invisalign First System (First) is a new type of orthodontic appliance for maxillary arch expansion in mixed dentition children. Till now, few studies have evaluated the expansion effects of First versus other appliances. What's more, most studies of arch expansion did not include a natural group to rule out growth effects. This prospective cohort study aimed to evaluate the dental and dentoalveolar effects using First or acrylic splint rapid maxillary expander (RME) in adolescents excluding growth factors.

MATERIALS AND METHODS

After screening by strict inclusion criteria and propensity score matching (PSM), fifty-one patients were included: First group (n = 17), RME group (n = 17), and natural growth (NG) group (n = 17). Nine indicators including dental arch width, dentoalveolar arch width, and inclination of the molars were measured on digital dental casts at baseline (T0) and six-month follow-up (T1). Paired t-tests were used for intra-group results, and two-sample independent t-tests were used for inter-group comparisons.

RESULTS

There was no significant increase in all indicators within six months in the NG group (p > 0.05). In the First group and RME group, all width indicators were significantly increased after treatment (p < 0.05). The RME group exhibited greater expansion than the First group in intercanine width, first interpremolar width, second interdeciduous molar width, first intermolar width, arch perimeter, intercanine dentoalveolar width, intermolar dentoalveolar width, and inclination of the molars (p < 0.05). Whereas, there was no significant difference in arch depth between the two treated groups.

CONCLUSIONS

Both First and RME can expand the maxillary arch in mixed dentition. In case of mild to moderate maxillary transverse deficiency (MTD), Invisalign First System could be a reasonable option. RME shows significant better efficiency of dental arch expansion than First, recommended for patients with severe MTD.

TRIAL REGISTRATION

This prospective study was registered on ClinicalTrials.gov (01/02/2022, registration number: ChiCTR2200056220). The trial was approved by the Ethical Committee of the Hunan Xiangya Stomatological Hospital Central South University (20,200,088), and informed consent was obtained from all subjects and their legal guardian(s).

Diagnostic value of cervical vertebral maturation stages for midpalatal suture maturation assessment: a study in the Chinese population

PURPOSE

To evaluate the correlation between cervical vertebral maturation stages (CVMS) and midpalatal suture maturation stages (MPSMS), and to analyze the diagnostic value of CVMS for the assessment of MPSMS.

METHODS

Cone beam computed tomography (CBCT) images of 233 subjects (8-20 years) were selected. The CVMS was determined using the McNamara and Franchi method, while the MPSMS was evaluated using the Angelieri method. Spearman rank correlation was used to analyze the results, and positive likelihood ratios were calculated to evaluate the diagnostic value of CVMS in identifying MPSMS.

RESULTS

Spearman rank correlation results showed a strong positive correlation (r = 0.867, P < 0.001) between CVMS and MPSMS. The positive likelihood ratios of CS12, CS4, and CS56 for the identification of stages AB, C, and DE were 12.17, 7.64, and 7.79, respectively. The values of the positive likelihood ratios of the other groups were less than five.

CONCLUSION

CS12 of the CVMS can be used as a reliable indicator for the assessment of MPSMS stage AB. From CVMS stage 4 forward, midpalatal suture maturation should be evaluated using CBCT.

Age, Sex, and Maxillary Position Are Associated with Successful Microimplant-Assisted Rapid Palatal Expansion in Adults

The purpose of this study was to investigate the possible predictors of success of microimplant-assisted rapid palatal expansion (MARPE) in skeletally mature patients. Additionally, factors associated with the amount of maxillary expansion were analyzed. Factors associated with MARPE success were analyzed in 53 adult patients (27 males, 26 females, mean age 25.8 ± 8.9 years, and range 18.0 to 56.6 years) who had a maxillary transverse deficiency greater than 2 mm and a cervical vertebral maturation stage of 6. Age at pretreatment (T1), sex, sutural bone density at T1, type of appliance, mode of microimplant fixation, and lateral cephalometric variables at T1 were considered for inclusion as predictors for MARPE success. In patients who showed successful maxillary skeletal expansion, the linear distances of maxillary widths were measured on cone-beam-computed-tomography images at T1 and after MARPE (T2), and factors associated with the amount of expansion were analyzed. In total, 41 of the 53 patients showed successful maxillary expansion. Age (p = 0.019), sex (p = 0.002), and A-N perp (p = 0.015) were significantly associated with the success of MARPE. The factors associated with the amount of maxillary skeletal expansion were SN-MP and midpalatal-suture density at T1. In conclusion, there is a greater chance of failure in male patients who are older and have maxillary retrusion. A greater amount of maxillary expansion can be expected in patients with a higher mandibular-plane angle and with lower midpalatal-suture density.

Skeletal, dentoalveolar, and buccal bone changes using hybrid and tooth-borne expanders for RME and SARME in different growth stages

Objective

To compare the skeletal, dentoalveolar and buccal bone thickness of tooth–bone-borne (Hybrid-H) and tooth-borne (TB) maxillary expanders used for rapid maxillary expansion (RME) in early and late adolescents and for surgically-assisted RME (SARME) in young adults.

Materials and methods:

This two-centre clinical study included initial and 6 months post-retention CBCT records of 60 patients (27 males, 33 females; mean age 15.7 ± 3.75 years). The cohort was divided into two groups according to the expander type (H or TB) and subdivided into a further three groups determined by cervical vertebrae maturation stages: early adolescents (EA), late adolescents (LA), and young adults (A). EA and LA patients underwent RME and young adults received a SARME.

Results:

The hybrid-designed appliance increased the internal skeletal maxillary width and nasal width more than the TB-designed appliance anteriorly in EA and posteriorly in SARME young adults. The TB expanders tipped and expanded the first premolars more than the Hybrid SARME expanders in young adults and caused a greater reduction in buccal alveolar bone thickness at the level of the first premolars and molars at the three growth stages.

Conclusion

The hybrid expanders, with relatively greater skeletal and nasal widening potential and fewer dentoalveolar side effects, were a favourable alternative to tooth-borne expanders for RME in the early and late adolescents, and for SARME in young adults.

Pulp changes from rapid maxillary expansion: A systematic review

INTRODUCTION

This study aimed to systematically review the current evidence on the occurrence of pulp changes as side effects from orthopaedic rapid maxillary expansion (ORME) or surgically assisted rapid maxillary expansion (SARME).

METHODS

An electronic search was performed in eleven databases. The eligibility criteria included clinical studies assessing vitality, sensibility or dimensions of the pulp chamber of permanent teeth before and after ORME or SARME, without restrictions on publication year or language. The risk of bias was analysed with the NIH 'Quality Assessment Tool for Before-After (Pre-Post) Studies with No Control Group' and the 'JBI for quasi-experimental studies' tool. The GRADE tool was used to assess the certainty of evidence.

RESULTS

The initial search resulted in 1,197 records, from which only seven before-after studies were included. There was a change in the pulpal blood flow (PBF) of maxillary incisors and canines up to 5 days after SARME, which gradually returned after 7 days to 3 months. After ORME, one study observed an increased PBF and one study observed a reduced PBF, which gradually returned after the end of expansion. Two studies observed that both ORME and SARME caused temporary changes in pulp sensibility. Three studies observed a significant reduction in the pulp chamber after ORME or SARME. The outcomes presented a very low certainty of evidence.

CONCLUSIONS

Although limited, the evidence shows that ORME and SARME caused temporary changes in pulp vitality and sensibility, with the possibility of inducing a reduction in pulp chamber dimensions.

Debates in pediatric obstructive sleep apnea treatment

Pediatric obstructive sleep apnea (OSA) is among the most common sleep-disordered breathing (SDB) diseases in children. Its high prevalence and multiple systemic complications lead to increasing numbers of children and families affected by OSA. Timely diagnosis and effective intervention in children with this condition is extremely important in improving their prognosis. The major approaches in the treatment of OSA in children are to eliminate the causes of upper airway obstruction and prevent and treat complications. Considering the specific individual differences in children's growth and development, as well as the diversity of etiologies in children's OSA, pediatric treatment strategies need to be precise, multidisciplinary, and individualized. First-line clinical treatment consists of surgical (adenotonsillectomy) and non-surgical therapies [including anti-inflammatory medications and non-invasive ventilation (NIV)]. However, a considerable controversy exists concerning the indications, treatment standards, and the evaluation of the efficacy of the aforementioned treatment methods. In this review, reviews and assessment of literature studies and multidisciplinary clinical experience were performed to analyze the application of each treatment and discuss controversial issues and future research directions. We suggest that the above interventions should be tailored to each child's needs, comorbidities, and the availability and expertise of the practitioner. The ideal case is when a multidisciplinary team of doctors together with the patients and their parents, or guardians, have a thorough discussion regarding the benefits and risks of all available treatment options and all agree on an effective treatment plan.

Rapid Palatal Expansion Should Not Be Trivialized: Two Case Reports of Unexpected Complications

Rapid maxillary expansion is one of the most common orthodontic procedures performed in the pediatric population, easy to accomplish and compliance free, therefore really effective. Nevertheless, a careful diagnosis and frequent clinical follow-up appointments are necessary during the first weeks of active treatment. The purpose of this article was to report two cases of unexpected complications during orthopaedic maxillary expansion, involving two 7-year-old female patients, one presenting a saddle nose with suborbital hematoma and the other one an asymmetric palatal expansion. In both cases, the clinical situation progressively relapsed during the months following expansion appliance removal.

Pyk2 deficiency enhances bone mass during midpalatal suture expansion

OBJECTIVE

To determine if Pyk2 deficiency increases midpalatal suture bone mass and preserves sutural integrity after maxillary expansion.

SETTING AND SAMPLE

Thirty-six male Pyk2 knockout (KO) and control (WT) mice at 6 weeks of age.

MATERIALS AND METHODS

Mice received nickel-titanium spring expanders delivering 0 g (no intervention control), 10 or 20 g force for 14 days. High-resolution micro-CT was used to determine bone volume/tissue volume (BV/TV), sutural width and intermolar width. Effects on osteoclasts, chondrocytes and suture morphology were determined by histomorphometry.

RESULTS

Pyk2-KO controls (0 g) had 7% higher BV/TV compared with WT controls. Expanded Pyk2-KO maxillae also exhibited 12% (10 g) and 18% (20 g) higher BV/TV than WT mice. Although bone loss following expansion occurred in both genotypes, BV/TV was decreased to a greater extent in WT maxillae (-10% at 10g; -22% at 20 g) compared with Pyk2-KO maxillae (-11% only at 20 g). Expanded WT maxillae also showed a greater increase in sutural width, intermolar width and fibrous connective tissue width compared with expanded Pyk2-KO maxillae. Moreover, osteoclast number was increased 77% (10 g) and 132% (20 g) in expanded WT maxillae, but remained unchanged in expanded Pyk2-KO, compared to their respective controls. Cartilage area and chondrocyte number were increased to the same extent in expanded WT and Pyk2-KO sutures.

CONCLUSIONS

These findings suggest that midpalatal suture expansion increases osteoclast formation in WT but not Pyk2-KO mice, leading to higher BV/TV in expanded Pyk2-KO maxillae. These studies suggest Pyk2-targeted strategies may be beneficial to increase bone density and preserve sutural integrity during maxillary expansion.

Interceptive Dentofacial Orthopedics (Growth Modification)

Although all dentofacial deformities involve deviation of skeletal and dental units that require correction, the timing and method of treatment can vary considerably. Growth is a key consideration when managing dentofacial deformities, because it has a direct impact on the timing and method of management. Some deformities may be intercepted and managed during growth, whereas others can only be definitively managed after cessation of growth. This article focuses on clinical considerations of growth in managing dentofacial deformities, and discusses methods of growth evaluation and interceptive orthodontic management strategies in different types of dentofacial deformities.