Titanium alloy vs. stainless steel miniscrews: an in vivo split-mouth study.

OBJECTIVE: To compare in vivo Titanium Alloy (TiA) with Stainless Steel (SS) miniscrews Temporary Anchorage Devices (TADs) using removal torque and Scanning Electron Microscopic (SEM) analysis. PATIENTS AND METHODS: 15 subjects (6 males and 9 females) who required maximum anchorage were recruited. For each patient, a TiA TAD and a SS TAD with same length and width were implanted following a randomized split-mouth study design. Retraction was carried out with nickel-titanium spring ligated directly from the anterior hooks of the archwire to the TADs to produce 90 to 100 g of force. When no further anchorage supplementation was needed, the TADs were removed. The removal torque values were registered with a digital screwdriver. After removal, the TADs were collected in a fixed solution and examined using SEM and X-ray microanalysis. RESULTS: All TADs remained intact, with a 100% success rate. There was no difference in removal torque between TiA and SS miniscrews (4.4 ± 1.3 N-cm and 5.1 ± 0.7 N-cm, respectively). All specimens' loss of gloss with signs of biological contaminations resulted in a dull implant surface. SEM photomicrographs of TiA miniscrews showed predominantly blood cells while SS miniscrews showed the precipitation of an amorphous layer with low cellular component. There was no difference in spectroscopic analysis between TiA and SS miniscrews. CONCLUSIONS: TiA and SS miniscrews had comparable removal torque values. SEM photomicrographs showed no evidence of osseointegration with both TADs having similar biological responses.

Correlations between dental malocclusions, ocular motility, and convergence disorders: a cross-sectional study in growing subjects.

OBJECTIVE: The purpose of the study was to analyze the association between dento-skeletal malocclusions, ocular motility, and convergence disorders in growing subjects. MATERIALS AND METHODS: 84 subjects (49 males, 35 females) with a mean age of 7.3±1.7 years were enrolled in a screening procedure for celiac disease at the Department of Gastroenterology of the University of Rome "Tor Vergata". Each child underwent an orthodontic, orthoptic, and ophtalmological examination. Pearson's Chi-Square test with Yates' correction and Fisher's exact test were conducted to assess the association between orthoptic defects and malocclusions (p<0.05). RESULTS: Ocular motility disorders were present in 44.9% of males and in 57.1% of females, while convergence defects were present in 10.2% of males and in 2.9% of females. Ocular motility disorders were more frequent in subjects with Angle Class III malocclusion (66.7%) than in subjects with Angle Class II (59.1%) and Class I (45.8%) malocclusion. Convergence defects were equally frequent in Angle Class I and Class II malocclusion (5.1%), while none subject presenting with Angle Class III malocclusion exhibited convergence defects. A statistically significant correlations was found between ocular motility disorders and unilateral cross-bite with midline deviation. CONCLUSION: Ocular motility defects had a significant greater prevalence in subjects presenting with unilateral cross-bite and midline deviation. The importance of role of orthodontic diagnosis among interdisciplinary treatment in growing children should be recognized.

Orthopaedic treatment effects of functional therapy on the sagittal pharyngeal dimensions in subjects with sleep-disordered breathing and Class II malocclusion.

The purpose of this cephalometric study was to evaluate the craniofacial changes induced by functional treatment of mandibular advancement with special regard to pharyngeal sagittal airway dimensions, tongue and hyoid bone position in subjects with sleep-disordered breathing (SDB) and dentoskeletal Class II malocclusions compared with an untreated Class II control group. 51 subjects (24 female, 27 male; mean age 9.9 ± 1.3 years) with Class II malocclusion and SDB consecutively treated with a functional appliance (Modify Monobloc, MM) were compared with a control group of 31 subjects (15 males, 16 females; mean age 10.1 ± 1.1) with untreated Class II malocclusion. For the study group, mode of breathing was defined by an otorhinolaryngologist according to complete physical examination. The parents of all participants completed a modified version of the paediatric sleep questionnaire, PSQ-SRBD Scale, by Ronald Chervin (the Italian version in 22 items form) before and after the trial. Lateral cephalograms were available at the start and end of treatment with the MM. Descriptive statistics were used for all cephalometric measurements in the two groups for active treatment changes. Significant, favourable skeletal changes in the mandible were observed in the treated group after T2. Significant short-term changes in sagittal airway dimensions, hyoid position and tongue position were induced by functional therapy of mandibular advancement in subjects with Class II malocclusion and SDB compared with untreated controls. After orthodontic treatment, a significant reduction in diurnal symptoms was observed in 45 of the 51 participants who had received an oral appliance. Orthodontic treatment is considered to be a potential therapeutic approach for SDB in children. Orthodontists are playing an increasingly important role in managing snoring and respiratory problems by oral mandibular advancement devices and rapid maxillary expansion.

Early treatment of Class III malocclusion with RME and facial mask: evaluation of dentoalveolar effects on digital dental casts.

AIM: To analyse the dental effects on digital dental casts in subjects with Class III malocclusion treated with bonded Rapid Maxillary Expansion and Facial Mask (RME/FM). MATERIALS AND METHODS: A study group sample (SG) of 29 subjects (13 females and 16 males) and mean age of 7.4 years (SD 1.2 years) was selected. A bonded RME was placed and activated 1/4 of a turn per day until overcorrection of the transverse width. At the end of expansion, patients were given FMs and treated at least to a positive overjet. The SG was compared with a control group (CG) of 21 prepubertal subjects (9 females; 12 males) presenting with normal occlusion and mean age of 7.9 years (SD 1.6 years). For each subject of the SG and CG initial (pretreatment, T1) and final (post-treatment, T2) digital dental casts were available. Significant in between-group differences were tested with the Student's t-test. RESULTS: The transverse dimension of the upper arch was significantly greater in SG vs. CG (IMAW: +2.6 mm; ICAW: +3.1 mm). Anterior arch length and arch depth were significantly smaller in SG when compared with CG (AAL: -3.2 mm, AD: -3.4 mm) at the end of therapy. CONCLUSION: The orthopaedic treatment with bonded RME/FM produced in subjects treated in the deciduous or early mixed dentition a significant expansion of the maxillary arch and mesialisation of the posterior teeth with a reduction of the arch depth.

Three-dimensional densitometric analysis of maxillary sutural changes induced by rapid maxillary expansion.

OBJECTIVE: This prospective study evaluated the density of the midpalatal and transverse sutures as assessed by low-dose CT before rapid maxillary expansion (T0), at the end of active expansion (T1) and after a retention period of 6 months (T2). METHODS: The study sample comprised 17 pre-pubertal subjects (mean age 11.2 years) with constricted maxillary arches. Total amount of expansion was 7 mm in all subjects. Multislice low-dose CT scans were taken at T0, T1 and T2. On the axial CT scanned images six regions of interest (ROIs) were placed along the midpalatal and transverse sutures and two in maxillary and palatal bony areas. Density was measured in Hounsfield units. Mann-Whitney U test and Friedman analysis of variance with post hoc tests were used (p < 0.05). RESULTS: The three ROIs in the midpalatal suture showed a significant decrease in density from T0 to T1, a significant increase from T1 to T2 and a lack of statistically significant differences from T0 to T2. Both ROIs located in the transverse suture showed a significant decrease in density from T0 to T1, followed by a non-significant increase in density from T1 to T2. CONCLUSIONS: At the end of the active phase of expansion a significant reduction in density along the midpalatal and transverse sutures was observed in all subjects. The sutural density of the midpalatal suture at T2 indicated reorganization of the midpalatal suture while the density along the transverse suture increased without reaching the pre-treatment values, possibly due to different morphology between midpalatal and transverse sutures.

Rapid maxillary expansion: effects on palatal area investigated by computed tomography in growing subjects.

AIM: The aim of this prospective study was to evaluate the effects of rapid maxillary expansion (RME) on the palatal area as assessed by low-dose CT before treatment (T0), at the end of active expansion (T1) and after a retention period of 6 months (T2). MATERIALS AND METHODS: The study sample comprised 17 prepubertal subjects (mean age 11.2 years) with constricted maxillary arches. Total amount of expansion was 7 mm in all subjects. Multi-slice low-dose CT scans were taken at T0, T1, and T2. On axial CT scanned images a circle line corresponding to the palatal area was drawn and the area inside the circle registered at all three observation times. The area was measured in mm². Statistical comparisons were carried out with Friedman test with post-hoc tests (P<0.05). RESULTS: The palatal area showed a significant increase from T0 to T1 and from T0 to T2 as a consequence of the opening of the midpalatal suture after RME. CONCLUSION: Opening the midpalatal suture by using orthopedic forces allowed to extend the area of the maxilla. After a 6-months retention period the palatal area demonstrated a stable increase due to a bone deposition along the midpalatal suture in both the anterior and posterior parts of the maxilla.

Comparison of different dose reduction system in computed tomography for orthodontic applications.

TO CORRELATE DIFFERENT CT SYSTEM: MSCT (multislice computed tomography) with different acquisition parameters (100KV, 80KV), different reconstruction algorithm (ASIR) and CBCT (cone beam computed tomography) examination in terms of absorbed X-ray dose and diagnostic accuracy.80 KV protocols compared with 100 KV protocols resulted in reduced total radiation dose without relevant loss of diagnostic image information and quality. CBCT protocols compared with 80 KV MSCT protocols resulted in reduced total radiation dose but loss of diagnostic image information and quality although no so relevant.In addition the new system applies to equipment ASIR applicable on MSCT allows 50% of the dose without compromising image quality.

Low-dose CT protocol for orthodontic diagnosis.

AIM: This was to correlate the dosimetric evaluation with high diagnostic accuracy by suggesting a protocol that significantly reduces the dose administered by a Dentascan exam without affecting diagnostic accuracy. MATERIALS AND METHODS: 17 patients were selected consecutively (7 males and 10 females) of a mean age of 11.2 (8-14 years) who sought orthodontic treatment. They needed CT control before and after treatment with RME to evaluate impacted canines. The study was performed using a multidetector 16-rows CT with two protocols that provided 2 different KV acquisition parameters: 80 KV or 120 KV. Radiation dose was evaluated in two ways: CTDI and DLP. Image quality was rated and the results were compared to identify significant differences in terms of image quality, radiation exposure and presence of artefacts. RESULTS: The 80 KV scanning has a significantly lower effective radiation dose compared to the 120 KV scanning (p <0.05). The images of all patients were used for comparing the protocols in terms of image quality. The mean scores for the 80 KV scanning images were 4.18 +/-0.81 and 4.41 +/-0.80 for dose obtained by 120 KV scanning. The median image quality was 4 (good) for both protocols. The 80 KV protocol allowed, as well as the 120 KV, a careful analysis by the orthodontist and the dental surgeon that together, based on this images, can choose the best line of treatment between several available options. CONCLUSION: 80 KV protocols compared with 120 KV protocols resulted in reduced total radiation dose without relevant loss of diagnostic image information and quality. The images were good enough to obtain information about the exact position of impacted teeth and to plan the best line of surgical treatment and mechanotherapy strategy.

Post-retention effects of rapid maxillary expansion on nasal cavity and on periodontal structures.

AIM: The aim of this study was to apply low-dose CT scans to evaluate the treatment and post-retention effects of RME on nasal cavity and periodontal effects. MATERIALS AND METHODS: CT scans of 17 subjects (7 males 10 females, mean age 11.2 years) were taken before RME (T0), at the end of the expansion phase (T1), and after a retention period of 6 months (T2). Measurements were performed on axial scans and on 3 different coronal scans. Statistical analysis was performed with ANOVA for repeated measures with post-hoc tests. RESULTS: Transverse dimensions of nasal cavity showed statistically significant T0-T1 increments at all the 3 coronal scans. All T0-T1 increments at the nasal levels showed a decrease in magnitude from the anterior to the posterior measurements. In the evaluation of T0-T1 changes, periodontal measurements were significant on the buccal aspect of banded teeth with a reduction in alveolar bone thickness. In the evaluation of T0-T2 changes, the lingual bone plate thickness resulted significantly increased. CONCLUSIONS: RME therapy induces a significant increase in the transverse dimension of the nasal cavity without permanent injuries to the periodontal bony support discernible at CT imaging. After six months the expansion of the nasal cavity results stable.