No Compliance Correction of Class II Malocclusion in Growing Patients Whit HERBST Appliance: A Case Report.

BACKGROUND: Class II malocclusion is the most common sagittal skeletal discrepancy, with a prevalent skeletal pattern of mandibular retrusion. The correction of mandibular retrusion with functional removable appliance needs a good patient's compliance; for this reason, some clinicians prefer to use no compliance apparatus. OBJECTIVE: Objective of the present therapy note is to demonstrate that the use of no compliance apparatus can provide a good correction of skeletal class II malocclusion. METHODS: In the present study, authors report a therapy note referred to a 10 years old patient, woman, affected by Class II, with mandibular retrusion and deep bite, treated in 2013 at the Dep. of Orthodontics of Messina University. An orthodontic treatment has been planned with the aim of stimulating mandibular growth; an Herbst appliance with a cantilever design, bonded on first maxillary and mandibular molars, has been used. After eleven months of functional therapy a bilateral molar class I have been obtained. RESULTS: In the therapy note proposed, authors obtained a resolution of mandibular retrusion, a correction of overjet, overbite and dental crowding in both arches, and a bilateral molar and canine class I has been achieved. CONCLUSION: Herbst appliance seems to be efficient in the correction of II Class Malocclusion, independently from patient's cooperation; moreover , early correction of Class II malocclusion with functional appliances produces several clinical advantages.

Standard and low-dose cone beam computer tomography protocol for orthognatodontic diagnosis: a comparative evaluation.

Considering the diagnostic capability offered by cone-beam computed tomography (CBCT), nowadays orthodontists often use this exam for treatment planning, especially in cases of impacted teeth, maxillary ipoplasia, orthognathic surgery etc. The aim of this study was to compare the radiation doses related to a conventional CBCT setting and that of a low dose protocol, usable in orthodontic practice. The absorbed organ doses were measured using an anthropomorphic phantom loaded with thermo-luminescent dosimeters related to sensitive organs (brain, bone marrow, salivary glands, thyroid, esophagus, oral mucosa, extrathoracic airways, lymph nodes). The device used was a MyRay Hyperion X9-11x5. The standard setting of the apparatus was 90 Kv, 36 mAs, CTDI/Vol 4.09 mGy, instead the low dose one was 90 Kv, 27 mAs, CTDI/Vol 2.89 mGy. Equivalent and effective doses have been calculated; the measurement of the effective doses was based on the ICRP recommendations. For the assessment of image quality, five readers, independent and experienced orthodontists, were asked to state if the images were sufficient enough to perform an orthodontic diagnosis. The lowest organ dose (5.01 microSv) was received by the esophagus during low dose CBCT acquisition. The highest mean organ dose instead (1227.67 microSv) was received by the salivary glands during conventional setting CBCT acquisition. Image quality has been considered sufficient for orthodontic diagnostic needs for both CBCT protocols. CBCT low dose setting should be preferred over the standard one in orthodontic practice, because it provides a significant lower radiation dose to the patients ensuring a good image quality. However, further studies are necessary to evaluate the opportunity of CBCT exams in orthodontic treatment planning.

Is static friction affected by aging and amount of elastomeric ligatures in orthodontic sliding mechanics? An in-vitro investigation.

In straight-wire mechanics, friction can significantly influence the forces expressed by wires. The aim of this study is to assess whether the aging and the sum of elastomeric ligatures affect the static friction during orthodontic space closure. A 0.017x 0.025-in SS was drawn throughout a 3-bracket experimental model and engaged with elastomeric ligatures. Before performing the test, the ligatures were soaked in artificial saliva for 48 hours (Group 1), 2 weeks (Group 2) and 4 weeks (Group 3); brand-new ligatures were also tested as control group (Group 4). The resistance to sliding (RS) was recorded at 3 different numerical configurations of ligatures using a customized testing machine and tests were repeated for ten times. Data of RS were statistically analysed by using two way analysis of variance (ANOVA) and Tukey's multiple comparison tests. RS was found to increase systematically when more elastomeric ligatures were included in the wire engaging system. At two weeks of immersion in artificial saliva elastomeric ligatures showed the lowest values of RS while they became significantly more frictional after immersion for 4 weeks. The results of this study showed that in multi-bracket orthodontic therapy, the RS increases with the number of elastomeric ligatures involved for arch-wire engagement. Differently from the frictional behavior of elastomeric modules, the aging of these ligatures does not influence their incremental effect of frictional forces.

Effects of rapid vs slow maxillary expansion on nasal cavity dimensions in growing subjects: a methodological and reproducibility study.

AIM: To evaluate the methodological feasibility of a RCT comparing skeletal changes of nasal cavity size obtained with RME and SME, assessed via CBCT. MATERIALS AND METHODS: Twenty Caucasian children with a mean age of 10.4 years were recruited and allocated to receive RME (10 subjects, mean age 10.4 years) or SME (10 subjects, mean age 10.5 years). INCLUSION CRITERIA: constricted maxillary arch, upper and lower first molars erupted, unilateral or bilateral posterior crossbite. EXCLUSION CRITERIA: age above 15 years, history of previous orthodontic treatment, periodontal disease, systemic disease affecting craniofacial growth, or craniofacial congenital syndrome. CBCT examinations were performed before treatment (T0) and 7 months after expander removal (T1). Changes of nasal width (NW), palatal width (PW) and total nasal volume (TNV) were assessed; palatal and nasal expansion was also calculated as a percentage of the increase of intermolar width IMW (PW% and NW%). RESULTS: The correlation between the first and the second readings ranged from 0.991 to 0.995 for linear measurements and was of 0.915 for volumetric measurements. The method error, as described by the value of ?, was in general less than 0.3 mm for linear measurements and 0.372 cm³ for volumetric measurements. All linear transverse skeletal and dental measurements and the nasal volume increased with both RME and SME protocols. CONCLUSION: The reported methodology can be reasonably used to investigate the transverse dimension of nasal cavity. The PW% and NW% parameters more accurately described the efficacy of the two expansion protocols as compared to their corresponding absolute measurement (PW and NW).

Unilateral condylar hyperplasia: diagnosis, clinical aspects and operative treatment. A case report.

BACKGROUND: Condylar hyperplasia of the mandible is an uncommon idiopathic disorder of the jaw characterised by increased volume of the condyle, unilaterally or bilaterally, leading to facial asymmetry, mandibular deviation, malocclusion and articular dysfunction. CASE REPORT: The authors present one case of unilateral condylar hyperplasia of a 16-year-old patient affected by severe facial asymmetry. Conventional X-rays examinations, multislice spiral CT and bone SPECT were used for the final diagnosis of primary condyle hyperplasia. The patient was treated with a combined orthodontic and surgical approach. CONCLUSION: Treatment of condylar hyperplasia with a combined orthodontic and surgical approach including condylectomy yield good aesthetic and functional outcomes.

Temporomandibular joint involvement in a cohort of patients with Juvenile Idiopatic Arthritis and evaluation of the effect induced by functional orthodontic appliance: clinical and radiographic investigation.

AIM: The aim of the study was to assess possible correlations between the clinical parameters of temporomandibular joint (TMJ) arthritis and pathologic MRI findings of the TMJ in patients affected by juvenile idiopathic arthritis (JIA), and the effect of a functional orthodontic therapy on the evolution of TMJ disorders. MATERIALS AND METHODS: A prospective clinical and nuclear magnetic resonance (NMR) investigation was conducted on a sample of 53 patients (41 female, 12 male) with JIA, treated for 24 months with an Andresen appliance. The involvement of TMJ was defined by clinical and radiological signs. NMR assessments were performed in closed and maximum opening mouth position before (T0) and at the end of functional orthodontic therapy (T1). RESULTS: Fifteen patients showed physical and radiologic TMJ abnormalities. Changes were not uniformly distributed among the different JIA subtypes. Patients with poliarticular JIA (≥5 peripheral joints affected) showed more destructive bony changes. No correlation existed between clinical symptoms and NMR alterations. Approximately one half of the patients experienced significant improvement of the TMJ and muscular pain using the Andresen appliance. CONCLUSION: The prevalence of TMJ involvement in patients suffering of JIA, and the improvement of TMJ and muscular pain associated with the use of functional appliance found in the present study, suggest an alert for TMJ dysfunction in patients with JIA and demonstrate the utility of functional orthodontic therapy in preventing the morbidities associated with TMJ arthritis in JIA.

A proportional correlation index for space analysis in mixed dentition derived from an Italian population sample.

AIM: The aim of this study was to establish a specific proportional correlation method for space analysis in mixed dentition applicable to the Italian population. MATERIALS AND METHODS: A retrospective analysis was performed on 300 plaster models taken from Italian subjects, 156 females and 144 males, aged between 12 and 25 years, visited at the Department of Orthodontic and Paediatric Dentistry of the University of Messina. RESULTS: The variance analysis (ANOVA) showed a high correlation between the dimension of the mesio-distal diameters of the four mandibular incisor and those of the upper canine and premolars. The correlation coefficient showed the existence of a directly proportional, positive intra- dependence between the two groups. DISCUSSION: The correlation tables used in the present study appear to be much more accurate if applied to groups of patients with similar ethnic backgrounds, thus explaining the differences between the various prediction indexes found in previous publications. CONCLUSION: This study highlights the need to develop specific values to fit the features of the different ethnic groups.

Genetic basis of non syndromic hypodontia: a DNA investigation performed on three couples of monozygotic twins about PAX9 mutation.

INTRODUCTION: Hypodontia, agenesis of one or of more teeth, is a common developmental dental anomaly. To date, over 200 candidate genes have been demonstrated to be active in tooth development. The genes Pax9 plays an important role in the initial stage of odontogenesis. Mutations of Pax9 are associated with autosomal dominant forms of oligodontia, the agenesis of more than six teeth and occasionally of premolars (MIM 604625) in humans. The aim of the present study was to screen the candidate gene causing the non syndromic hypodontia, with agenesis of upper third molars and upper lateral incisors, in three couples of twins. MATERIALS AND METHODS: Peripheral blood samples taken for routine laboratory investigations were used for genotyping. Total genomic DNA was extracted from the buffy coat of 1 ml of EDTA blood samples using phenol-chloroform and the salting out procedure. RESULTS: The insC mutation (nt793, exon4) was observed in the sequencing results by the use of the primers hPAX9ex4F and hPAX9ex4R. InsC raises a frameshift mutation that introduces a nonsense codon so the mRNA activity results impaired. CONCLUSION: In this work, it is described how the same mutation is responsible for a form of dental agenesis--less severe in the number of missing teeth--leading to hypodontia instead of oligodontia. Therefore, it is possible that mutations of the same gene cause different phenotypes; so we can presume that some modifier genes moderate the effect of the first mutation.

Myotonic dystrophy and craniofacial morphology: clinical and instrumental study.

AIM: The aim of this study is to assess if, and to what extent, myotonic dystrophy can affect the craniofacial growth pattern. MATERIALS AND METHODS: The research was conducted on a sample of 27 patients with Steinert's myotonic dystrophy (study group). Each subject underwent a clinical examination with impression-taking and intra- and extraoral photographs. A latero-lateral projection teleradiography in the mirror position was also taken and a cephalometric examination was performed. The assessed values were compared with those obtained from a group of healthy subjects (control group). RESULTS: Statistical analysis of the data obtained from the myotonic patients who developed the disease during the growth phase revealed alterations in the transversal plane and, to an even greater extent, the vertical one, with a high frequency of anterior open bite. Discussion and conclusions Regarding the pathogenesis of these types of skeletal dysplasias, the authors hypothesise a posterior rotation growth pattern, resulting from gravitational force prevailing over the deficit of the elevator muscles.

Correlations between cephalic posture and facial type in patients suffering from breathing obstructive syndrome.

AIM: In this teleradiographic study, the authors investigate the correlations between facial kind, breathing pattern and cephalic posture. METHODS The research was conducted on a 94 schoolchildren sample. For each patient teleradiographic analysis in-L-L projection and rhinomanometric examination were performed. On the basis of clinical evidences, rhinomanometric results and nasopharyngeal space evaluation, the sample was divided into two groups: the first one included 36 oral breather patients (OB), the second one 58 nasal breathers (NB). RESULTS: The two groups do not differ significantly, with the exception of divergence values, frequently higher in OB than NB. The comparison of craniofacial features and cephalic posture among the groups points out to correlations between large craniocervical angle and skeletal Class II, mandibular retrognathia and increased gonial angle, respectively, not related to breathing patterns. CONCLUSION: According to the authors' results, it can be stated that morphological characteristics classically associated with breathing obstructive syndrome could be induced by altered cephalic posture instead.

Evaluation of skin dose in a low dose spiral CT protocol.

AIM: The authors evaluated radiation and skin doses absorbed by the eye lens, as well as the parotid and thyroid glands, during a low dose maxillary spiral computed tomography (CT). METHODS: Three spiral CTs were carried out, one after the other, changing from time to time MAS, pitch factor, Kv and consequently, CTDI/Vol, until the minimum values detectable by the equipment were reached (MAS 28, Kv 80, CTDI/Vol 2.5, Pitch 1). The quality of the images was evaluated on the grounds of being able to visualise the anatomic structures considered. The amount of radiation effectively absorbed by the soft tissue (skin doses) can be measured with the help of dosimeters placed at the level of eye lens, parotid and thyroid glands. The spiral CTs were performed with a Siemens 16 CT sensation machine, using a tissue equivalent Head-Neck RT Humanoid phantom. RESULTS: From the results of this study, it appears possible to obtain high quality images, useful for diagnosing numerous skeletal pathologies in orthodontics, reducing of about 90% the radiation dose per unit of volume and, at the same time, reducing the soft tissue (skin) dose of about 85% when compared to pre-established settings. CONCLUSION: The authors conclude their research emphasizing the possibility of applying low dose protocols, not only in orthodontics but in any dental field, whenever a spiral CT is needed for a more detailed diagnosis.