Expansion of permanent first molars with rapid maxillary expansion appliance anchored on primary second molars

Assessment of cephalometric parameters and correlation with the severity of the obstructive sleep apnea syndrome

BACKGROUND

In individuals diagnosed with obstructive sleep apnea syndrome (OSAS), variations in craniofacial structure have been inconsistently documented, showing differing degrees of alteration between obese and nonobese patients. In addition, sleep disturbance has also been shown to induce disequilibrium in this population of patients. This pilot observational study aimed to assess craniofacial values in obese and nonobese subpopulations of patients with OSAS and their correlation and association with the severity of OSAS. We also assessed whether OSAS patients are characterized by an impaired equilibrium in relation to and associated with the severity of OSAS.

METHODS

We included all consecutive adult patients with OSAS. Through cephalometry, we assessed the upper (UPa-UPp) and lower (LPa-LPp) pharynx diameters, superior anterior facial height (Sor-ANS), anterior facial height (ANS-Me), anterior vertical dimension (Sor-Me), posterior facial height (S-Go) and craniovertebral angle (CVA). Furthermore, we analyzed postural equilibrium through a stabilometric examination.

RESULTS

Forty consecutive OSAS patients (45% female with a mean age of 56 ± 8.2 years) were included. The subgroup of nonobese patients had a reduced UPa-UPp (p = 0.02). Cephalometric measurements were correlated with the severity of OSAS in nonobese patients, whereas only Sor-ANS was correlated with the severity of OSAS in the obese subpopulation. In the overall population, altered craniofacial values are associated with severe OSAS. Although there are differences in equilibrium between obese and nonobese OSAS patients, the stabilometric measurements were not correlated or associated with OSAS severity.

CONCLUSION

Altered craniofacial values and compromised equilibrium in OSAS patients are linked to OSAS severity. Therefore, the management of OSAS should be tailored not only to weight management but also to craniofacial and postural rehabilitation to enhance patient outcomes.

Factors Influencing Appliance Wearing Time during Orthodontic Treatments: A Literature Review

This review aims to analyze the multiple factors affecting patients’ level of compliance (how much they wear removable devices/clear aligners) during orthodontic treatments and to investigate the available methods and devices to monitor the appliance wearing time and to improve it. A literature search was conducted on electronic databases (Pubmed, Scopus, and Google Scholar). The results of the present study suggest that compliance indicators may misestimate the intraoral wearing time. Compliance is affected by patient-related factors (age, personality traits, the importance of personal appearance, self-perception of malocclusion), appliance-related factors (visibility, pain/discomfort), and clinician-related factors (trust, clear and complete communication, motivation). The motivation of pre-pubertal patients is mostly external, while adolescents/young adults have intrinsic motivation for orthodontic treatment. Patients’ self-reports tend to overestimate the appliance wearing time. Even if there is a lack of evidence, teledentistry might improve patients’ awareness of being monitored, thus increasing the time for which orthodontic devices are worn. Compliance is a key factor for clear aligner treatments, but high-quality studies focusing on this aspect are missing. Further studies should focus on how to handle the lack of cooperation and how to increase compliance in order to maximize the treatment’s results.

Parathyroid hormone promotes maxillary expansion and reduces relapse in the repeated activation maxillary expansion rat model by regulating Wnt/β-catenin pathway

Background

Constricted maxillary bone is a common skeletal deformity, which may lead to crowding and posterior crossbite. Mid-palatal suture expansion is often used to increase the maxillary width, but its skeletal effects are limited and tend to relapse, even with prolonged retention. We hypothesized that parathyroid hormone (PTH) may reduce the relapse of maxillary expansion.

Methods

We established a novel rat maxillary expansion model using palatal tubes with an insertable “W”-shaped spring which can be repeatedly activated. A total of 32 male healthy Wistar rats were randomly divided into six groups: the control group, the PTH group, the expansion group, the expansion + PTH group, the expansion + relapse group and the expansion + PTH + relapse group. All animals in the first 4 groups were killed after 10 days and the 2 relapse groups were killed after 15 days. The maxillary arch widths and histological staining were used to assess the expansion and relapse effects. The immunohistochemical staining, micro-CT, RT-qPCR and Western blot were used to evaluate the bone remodeling during expansion.

Results

The suture width was increased by the expansion device, and the repeated activation maxillary expansion rat model showed better expansion effects than the conventional model. PTH significantly promoted the expansion width and reduced the relapse ratio. Meanwhile, in the expansion + PTH group, histological and immunohistochemical staining showed that osteoblasts, osteoclasts, new cartilage and osteoid were significantly increased, micro-CT showed increased bone mass, and PCR and Western blot results confirmed up-regulation of RANKL, β-catenin, type II collagen and OCN.

Conclusion

The novel repeated activation maxillary expansion rat model has better effects than the conventional model. PTH enhances the maxillary expansion and reduces its relapse by regulating Wnt/β-catenin and RANKL pathways. PTH administration may serve as an adjunctive therapy in addition to mechanical expansion for treatment of maxillary constriction.

Long-term effect on adenoid dimensions and craniocervical angulation after maxillary expansion with fixed or functional appliances

Background

Maxillary expansion is a common orthodontic procedure that could have a positive effect also on airway patency. The aim of the present study was to evaluate the long-term effects of rapid maxillary expansion (RME) on nasopharyngeal area and cranio-cervical angulation in growing patients, compared to controls treated with a function-generating bite appliance (FGB).

Material and Methods

Sixty patients aged 6-14 consecutively treated with RME or FGB were selected retrospectively and divided into two groups. Lateral cephalograms taken before and after treatment were retrieved, and the nasopharyngeal area, delimited superiorly by a sella-posterior nasal spine (PNS) line and inferiorly by a basion-PNS line, and the cranio-cervical angulation were measured.

Results

The mean observation time was 17.6 ± 8 months. No differences were present between the two groups regarding age and gender. The nasopharyngeal area increased significantly in both groups after treatment, but with no statistically significant difference between them. The cranio-cervical angulation showed no differences within or between groups.

Conclusions

Maxillary deficiency treatment with either RME or FGB was followed by a comparable increase in nasopharyngeal area.

Key words:Rapid maxillary expansion, Airway, Nasopharyngeal area, Adenoid.

Prevalence of maxillary canine impaction in skeletal Class III malocclusions compared to Class I malocclusions

Background

The aim of the present investigation was to evaluate if an orthodontic population of Class III malocclusion patients shows a different prevalence of maxillary canine impaction than Class I subjects.

Material and Methods

Fifty-eight subjects were retrospectively selected and assigned to the Class I group (n= 32) or the Class III group (n= 26), depending on the ANB and WITS values. Lateral cephalograms were used to collect angular and linear measurements that described the skeletal and dental maxillary features of the subjects, while orthopantomography was used to assess the impaction or the correct eruption of the maxillary canines. An independent samples T-test or a Mann-Whitney U-test was used to compare the cephalometric values between the two groups, while a chi-squared test was used to evaluate the distribution of maxillary canine impaction between the two groups.

Results

No statistically significant difference was found for the cephalometric variables, and the frequency of canine impaction showed no difference between the Class III and Class I subjects.

Conclusions

Patients with skeletal Class III malocclusions did not show a different prevalence of canine impaction; therefore, such skeletal features cannot be used as a diagnostic aid for assessment of the risk of maxillary canine impaction. Key words:Skeletal Class III, Angle Class III, maxillary canine impaction, tooth impaction.

Does muscular activity related to vertical facial divergence influence the time needed for orthodontic extrusion of palatally impacted maxillary canines? A retrospective study

Background

The aim of the present study was to evaluate if the different muscular activity correlated to different degrees of facial divergence has an effect on the time needed to extrude a palatally impacted maxillary canine.

Material and Methods

Twenty-six patients were retrospectively selected, all treated with a specific cantilever appliance that allows extrusion of the impacted canine applying a physiologic amount of force below 0.6 N in a predictable way. For all the patients, pre-treatment cephalometric tracings were used to evaluate facial divergence through the FMA angle, the angle between the maxillary and mandibular plane, and the angles between the occlusal plane and either the maxillary and mandibular plane. Linear bivariate regression was calculated to evaluate if facial divergence can predict the time needed for canine extrusion.

Results

The linear regression model was not able to predict extrusion time from variables explaining the facial divergence.

Conclusions

Palatally impacted maxillary canines can be treated with the application of physiologic extrusion force regardless of patients’ facial divergence and muscular activity.

Key words:Impacted canines, cantilever, facial divergence, muscular activity.