An adolescent treated with rapid maxillary expansion presenting with strabismus: a case report

Skeletal and dental effects of function-generating bite appliance compared to rapid palatal expander and untreated controls

INTRODUCTION

Maxillary expansion is a fundamental interceptive orthodontic treatment, which can be achieved through either a rapid expansion protocol or functional devices. However, no data exist about the efficacy of functional devices in achieving skeletal expansion. Therefore, the aim of this study was to compare the effects of the rapid palatal expander (RPE) and the function-generating bite type M (FGB-M) on the transversal dimension of the maxilla, and on the maxillary and mandibular dental arch width.

METHODS

One hundred eighty-one skeletal Class I patients, aged between 6 and 12 years and with a cervical vertebral maturation stage II or III, with maxillary transversal deficiency were retrospectively enrolled; among these 55 were treated with FGB-M, 73 were treated with RPE and 51 were untreated subjects retrieved from historical databases. The pre-treatment (T0) and post-treatment (T1) frontal cephalograms were retrieved, and the maxillary and mandibular widths, and the distance between upper and lower first molars were measured. T1-T0 interval was of 17.3 months (RPE), 24.6 months (FGB-M) and 18.2 months (controls).

RESULTS

The statistical analysis showed that there were no statistically significant differences between the RPE and FGB-M groups regarding skeletal and dental expansion, while the untreated control group differed significantly from the other two groups.

CONCLUSION

The comparison between patients treated with RPE and FGB-M showed that there were no statistically significant differences between the RPE and FGB-M groups regarding the amount of skeletal expansion and dental arch width, suggesting that both appliances can be used to achieve similar results.

Unusual systemic and nondental effects of maxillary expansion therapy: A comprehensive and updated review of literature

In dental practice, pediatric patients with a wide range of manifestations of malocclusion viz. crossbite, dental crowding, and skeletal Class III due to transverse discrepancy of the abnormally constricted maxilla or palate are found. However, the dental management of such kind of malocclusion with narrow palate needs a meticulous dental evaluation. Appliances used for treating such malocclusion conditions may include Slow-Maxillary Expansion (SME) or Rapid Maxillary Expansion (RME) orthodontic or orthopedic appliances. Considerable success has been described in the literature using the maxillary/palatal expansion modality. Unusual systemic and nondental effects of expansion appliances therapy have been described in some scientific studies. However, no comprehensive review article has been published describing the nondental and systemic effects of RME/SME therapy in Pediatric Dentistry. Considering the above scenarios, the updated and comprehensive review of the relevant literature is necessary for health professionals. Dental professionals including pediatric dentists and orthodontists need to consider such untoward or unexpected effects of RME/SME treatment modality. Hence, the current comprehensive review article has been written with the aim to meticulously describe the relevant scientific literature about nondental/extraoral and systemic effects of RME/SME appliances.

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.

Evaluation of changes in orbital volume in adult female patients with maxillary transverse deficiency treated with a maxillary skeletal expander

OBJECTIVES

The effects of using a maxillary skeletal expander (MSE) on the orbital volume and width between periorbital bones in the treatment of adult female patients with maxillary transverse deficiency (MTD) were evalua⁃ted.

METHODS

A total of 20 adult female patients with MTD with an average age of (22.60±6.29) years were included in the study. The patients were treated with MSE. Cone beam computed tomography was performed before expansion (T0) and no more than 3 weeks after expansion (T1). Orbital volume and periorbital bone width were measured with Mimics 21.0 and analyzed with SPSS 20.0. Paired t-test was performed, and a P value of <0.05 indicated significant difference.

RESULTS

After expansion, the orbital volume increased by (346.80±275.31) mm3 (P<0.05). The width between the right and left zygomaticomaxillary sutures increased by (1.69±0.57) mm (P<0.05), and the width between the right and left infraorbital points increased by (1.71±0.70) mm (P<0.05). However, the width between the right and left frontozygomatic sutures increased by (0.15±0.32) mm (P>0.05). Finally, the width between the right and left supraorbital points increased by (0.23±0.52) mm (P>0.05).

CONCLUSIONS

The maxillary skeletal expander slightly expanded the orbital volume in the adult female patients and increased the lateral widths of the periorbital bones.

Kraniomandibuläre Dysfunktion und Asthenopie – Literaturübersicht mit Fallbeispielen

Hintergrund

Kann ein latentes Schielen (Heterophorie) nicht fusionell überwunden werden, treten asthenope Beschwerden wie intermittierende Doppelbilder, Blendempfindlichkeit, retrobulbäres Druckgefühl, Visusschwankungen und Kopfschmerzen auf. Häufig ist der zugrunde liegende Pathomechanismus unklar. Neben verschiedenen ophthalmologischen und neurologischen Erkrankungen wird auch die kraniomandibuläre Dysfunktion (CMD) als möglicher Auslöser einer Asthenopie beschrieben.

Material und Methode

Präsentation von 3 Fallbeispielen von Patientinnen mit CMD und Asthenopie und Literaturübersicht.

Resultate

Im Rahmen der Literaturrecherche wurden einige Arbeiten zur Anatomie und zu neurologischen Verschaltungen zwischen dem trigeminalen und dem okulomotorischen System gefunden, die über Veränderungen der Pupillenweite, der Konvergenz und der Stellung der Augen mögliche pathomechanische Zusammenhänge zwischen einer Malokklusion bzw. CMD und Heterophorie mit Asthenopie postulieren.

Schlussfolgerung

Bei Beschwerdepersistenz von asthenopen Beschwerden trotz optimaler orthoptischer Therapie kann eine weiterführende kieferorthopädische Abklärung in Betracht gezogen werden.

Evaluation of Vision in Gnathological and Orthodontic Patients with Temporomandibular Disorders: A Prospective Experimental Observational Cohort Study

Objectives:

Temporomandibular disorders (TMDs), orthodontic diseases, and vision dysfunctions seem to be strictly related. The purpose of this study was to prove the relationship, to evaluate the prevalence and the distribution of vision defects in dysfunctional and orthodontic patients, and to establish the type of the relationship.

Materials and Methods:

A total of 100 patients with TMDs were selected and studied through epidemiological analyses of the following factors: gnathological parameters (temporomandibular joint pathologies according to Diagnostic Criteria for Temporomandibular Disorders); occlusal and skeletal parameters (overjet, overbite, dental class, transversal discrepancies, and mandibular asymmetry); and orthoptic parameters (refractive defects and oculomotor diseases). A prospective experimental observational cohort study was conducted. A comparison with the average frequency of vision defects of the Italian population was performed. The prevalence of vision defects was evaluated. All gnathological and orthodontic parameters were associated with the orthoptic ones. A descriptive and statistical analysis of the data was carried out with the Statistical Package for the Social Sciences software; z test (P < 0.05), frequency analysis (frequency >50%), chi-square test, and Student’s t test (P < 0.05) were performed. The scientific consistency was evaluated by using the scientific criteria of Bradford Hill.

Results:

The comparison with the Italian population showed a higher frequency of refractive defects in the study sample (P < 0.001). The most frequent vision defects were phorias (92%) and tropia (3%). The increased frequency of ocular convergence reduction in the presence of disc displacement with reduction was significant (n = 28; 60%; P < 0.05). In the presence of asymmetry, low frequencies of astigmatism (n = 18; 30%) were observed compared to its absence (n = 22; 54%) (P < 0.05) and high frequencies of motor ocular deviations (n = 59; 100%) were observed compared to its absence (n = 36; 88%) (P < 0.05). In the presence of headache, low frequencies of emmetropia (n = 13; 22%) and higher frequencies of hyperopia (n = 18; 30%) were observed (P < 0.05). Two of five scientific criteria of Bradford Hill were met.

Conclusion:

It seems to emerge a possible positive relationship between TMD and vision defects. In particular, the most interesting associations were found between functional or skeletal orthognathic alterations and oculomotor dysfunctions. However, it was not possible to establish the type of relationship.

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.

Association of Visual Defects and Occlusal Molar Class in Children

Purpose

The purpose of this cross-sectional study is to evaluate the presence of any correlations between dysfunctions related to visual impairments and dental occlusion.

Methods

The test group included 34 subjects (21 males and 13 females; mean age 11 ± 2 years) randomly selected with the following inclusion criteria: absence of any diagnosis for problems at visual level except those related to refractive defects, visual acuity of at least 1.0, absence of any syndrome or malformation in the craniofacial area, good general health, and absence of any systemic disease able to influence the vision or the craniofacial growth. They underwent visual clinical tests to evaluate the presence of fusional vergence defects and amplitude. Each patient underwent an orthodontic clinical exam and the occlusal molar relationship of each subject was recorded and considered as occlusal variable. A statistical analysis with Chi-Squared test was performed in order to analyze the associations between the visual defects and the occlusal variable.

Results

A statistically significant association between the molar occlusal relationship and the occurrence of exodeviations was observed. The percentage of subjects presenting fusional amplitudes with convergence lower of the cut-off value was statistically significantly higher in the group of occlusal molar second class.

Conclusions

The results obtained show that there is an association between occlusal second molar class and fusional vergence defects.

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

Background

To evaluate how the amount of expansion of the primary second molars, the patient’s age, and the skeletal maturation stage influence the amount of expansion at the level of the permanent first molars.

Material and Methods

Fifty-five patients aged between 6 and 11 years with a cervical vertebral maturation stage of CS1 or CS2 were retrospectively selected. The intermolar width was measured before and after expansion to evaluate the amount of expansion achieved at the level of the primary second molars and the permanent first molars. Stepwise multiple linear regression was used to evaluate how the amount of primary molars expansion, the patient’s age, and the cervical vertebral maturation stage predict the amount of permanent molar expansion.

Results

A significant regression equation was found, and for every 1 mm of primary molar expansion, 0.91 mm of permanent molar expansion can be expected. An age between 6 and 11 years and the CS1 or CS2 skeletal maturation stage were not significant predictors of permanent molar expansion.

Conclusions

A rapid maxillary expansion appliance anchored on primary second molars is effective in expanding the permanent molars to correct a transverse maxillary deficiency in prepubertal patients, transferring the risks associated with the large forces used to the primary teeth.

Key words:Maxillary expansion, transversal deficiency, primary molars.

Dental Occlusion and Ophthalmology: A Literature Review

Stomatognathic system is strictly correlated to other anatomical regions; many studies investigated relationship between temporomandibular joint and posture, several articles describe cranio-facial pain from dental causes, such as trigger points. Until now less interest has been given to connections between dental occlusion and ophthalmology, even if they are important and involving. Clinical experience in dental practice claims that mandibular latero-deviation is connected both to eye dominance and to defects of ocular convergence. The trigeminal nerve is the largest and most complex of the twelve cranial nerves. The trigeminal system represents the connection between somitic structures and those derived from the branchial arches, collecting the proprioception from both somitic structures and oculomotor muscles. The intermedius nucleus of the medulla is a small perihypoglossal brainstem nucleus, which acts to integrate information from the head and neck and relays it on to the nucleus of the solitary tract where autonomic responses are generated. This intriguing neurophysiological web led our research group to investigate anatomical and functional associations between dental occlusion and vision. In conclusion, nervous system and functional pathways strictly connect vision and dental occlusion, and in the future both dentists and oculists should be more and more aware of this correlation for a better diagnosis and therapy.

Evaluation of cervical posture following rapid maxillary expansion: a review of literature

Objective:

The aim of this article is to elucidate the state of the art about how rapid maxillary expansion (RME) produces changes in natural head position (NHP) in terms of cephalometric angles or inclinometer data during the growth period, according to the available literature.

Methods:

Electronic search was done from January 2002 to June 2012 on PubMed, Cochrane and Scopus databases; in addition manual search was conducted as well. According to keywords, eleven papers were eligible for our purpose, but definitely six papers were selected in agreement with the inclusion/exclusion criteria.

Conclusions:

The current literature suggests that the potential relationship between RME and NHP is still unclear. In fact, although the change in the position of the head after the rapid palatal expansion is evident clinically, current orthodontic literature does not provide conclusive evidence about the nature of this relationship