Giovanni Matarese

Effectiveness of orthodontic treatment with functional appliances on mandibular growth in the short term

INTRODUCTION The aim of this study was to analyze the current literature for the best evidence (randomized clinical trials) about the efficacy of functional appliances on mandibular growth in the short term. METHODS A survey of articles published up to September 2009 was performed by using the following electronic databases: PubMed, Embase, Ovid Medline, Cochrane Central Register of Controlled Trials, Web of Science, LILACS, and Google Scholar. The reference lists of the retrieved articles were hand-searched for possible missing articles. No language restriction was applied during the identification of the published studies. A methodologic scoring process was developed to identify which randomized clinical trials were stronger methodologically. The selection process and the quality assessment were undertaken independently and in duplicate by 2 authors. A meta-analysis was attempted by using random-effects models. Clinical and statistical heterogeneity was examined, and a sensitivity analysis was performed. RESULTS Electronic searches identified the following items: 146 articles were retrieved from PubMed, 45 from Cochrane Central Register of Controlled Trials, 29 from Ovid, 42 from LILACS, 628 from Web of Science, and 1000 from Google Scholar. Thirty-two articles fulfilled the specific inclusion criteria and were identified as potentially appropriate randomized clinical trials to be included in this meta-analysis. Only 4 articles, based on data from 338 patients (168 treated vs 170 controls) with Class II malocclusion in the mixed dentition, were selected for the final analysis. The quality analysis of these studies showed that the statistical methods were at the medium-high level. The outcome measurements chosen to evaluate the efficacy of the various functional appliances were Co-Pg, Pg/Olp + Co/Olp, and Co-Gn and the values were annualized and standardized to a uniform scale with the standardized mean differences (SMD). The results of the meta-analysis from the random-effects model showed a statistically significant difference of 1.79 mm in annual mandibular growth of the treatment group compared with the control group (SMD = 0.61, 95% CI, 0.30 to -0.93; chi-square test, 5.34; 3 df; P = 0.15; I(2) = 43.9%; test for overall effect, Z = 3.83 and P = 0.0001). The sensitivity analysis showed a substantially similar outcome of 1.91 mm (SMD = 0.65, 95% CI, 0.25 to 1.25; chi-square test, 4.96; 2 df; P = 0.08; I(2) = 59.7%; test for overall effect, Z = 3.19 and P = 0.001). CONCLUSIONS The analysis of the effect of treatment with functional appliances vs an untreated control group showed that skeletal changes were statistically significant, but unlikely to be clinically significant.

Biomonitoring of DNA damage in peripheral blood lymphocytes of subjects with dental restorative fillings

Dental fillings provide a major iatrogenic exposure to xenobiotic compounds due to the high prevalence of surface restorations in developed countries. Experimental data suggest that both amalgams, which contain mercury, and resin-based dental materials cause an impairment of the cellular pro- and anti-oxidant redox balance. The aim of this study was to assess the potential genotoxicity of dental restorative compounds in peripheral blood lymphocytes of young exposed subjects compared with controls. The study examined, by use of the comet assay, 68 carefully selected subjects taking into account the major known confounding factors. In the 44 exposed subjects, the mean numbers of restored surfaces was 3.0 and 3.8 in males and females, respectively. Tail length, percentage of DNA in the tail, tail moment or Olive tail moment were twofold higher in the exposed group than in unexposed controls, with significant differences. No significant difference was observed between amalgam and composite fillings. Furthermore, as shown by multivariate analysis, the association between dental fillings and DNA damage was enhanced by the number of fillings and by the exposure time. Among the lifestyle variables, a moderate physical activity showed a protective effect, being inversely correlated to the DNA damage parameters evaluated. On the whole, the use of DNA-migration allowed us to detect for the first time the potential adverse impact on human health of both kinds of dental filling constituents, the amalgams and the methacrylates. The main mechanism underlying the genotoxicity of dental restorative materials of various nature may be ascribed to the ability of both amalgams and methacrylates to trigger the generation of cellular reactive oxygen species, able to cause oxidative DNA lesions.

Effects of orthopedic maxillary expansion on nasal cavity size in growing subjects: A low dose computer tomography clinical trial

OBJECTIVE The aim of this retrospective clinical trial was to evaluate the effects of rapid maxillary expansion on skeletal nasal cavity size in growing subjects by use of low dose computer tomography. METHODS Eight Caucasian children (three male; five female) with a mean age of 9.7 years (SD±1.41) were the final sample of this research that underwent palatal expansion as a first phase of orthodontic treatment. The maxillary expander was banded to the upper first molars and was activated according a rapid maxillary expansion protocol. Low-dose computer tomography examinations of maxilla and of the low portion of nasal cavity were performed before inserting the maxillary expander (T0) and at the end of retention (T1), 7 months later. A low-dose computer tomography protocol was applied during the exams. Image processing was achieved in 3 steps: reslicing; dental and skeletal measurements; skeletal nasal volume computing. A set of reproducible skeletal and dental landmarks were located in the coronal passing through the first upper right molar furcation. Using the landmarks, a set of transverse linear measurements were identified to estimate maximum nasal width and nasal floor width. To compute the nasal volume the lower portion of the nasal cavity was set as region of interest. Nasal volume was calculated using a set of coronal slices. In each coronal slice, the cortical bone of the nasal cavity was identified and selected with a segmentation technique. Dependent t-tests were used to evaluate changes due to expansion. For all tests, a significance level of P<0.05 was used. RESULTS Rapid maxillary expansion produced significant increases of linear transverse skeletal measurements, these increments were bigger in the lower portion of the nasal cavities: nasal floor width (+3.15 mm; SD ± 0.99), maximum nasal width (+2.47 mm; SD ± 0.99). Rapid maxillary expansion produced significant increment of the total nasal volume (+1.27 cm(3) ± SD 0.65). The anterior volume increase was 0.58 cm(3) while the posterior one was 0.69 cm(3). CONCLUSION In growing subjects RME is able to significantly enlarge the dimension of nasal cavity. The increment is bigger in the lower part of the nose and equally distributed between the anterior e the posterior part of the nasal cavity.

Immunohistochemical analysis of TGF-β1 and VEGF in gingival and periodontal tissues: A role of these biomarkers in the pathogenesis of scleroderma and periodontal disease

Periodontal disease is characterized by inflammation and bone loss. The balance between inflammatory mediators and their counter-regulatory molecules may be fundamental for determining the outcome of the immune pathology of periodontal disease. Transforming growth factor-β (TGF-β) and vascular endothelial growth factor (VEGF) represent a family of polypeptide proteins involved in the inflammation and regulation of immune responses, especially in rheumatic disease. The relationship between these growth factors and periodontitis has resulted in a new field of osteoimmunology and provides a context for better understanding the pathogenesis of periodontal disease. Therefore, the aim of this study was to compare the protein expression profile of these inflammatory mediators in 90 patients divided in three groups: healthy control, chronic periodontitis and in rheumatic disease, scleroderma. The findings presented here highlight that biomarkers, such as TGF-β1 and VEGF, play a key role in the evolution of the immune response, which in turn influences the outcome of disease establishment.

Load–deflection characteristics of superelastic and thermal nickel–titanium wires

The aim of this study was to investigate the mechanical properties of superelastic and thermal nickel-titanium (NiTi) archwires for correct selection of orthodontic wires. Seven different NiTi wires of two different sizes (0.014 and 0.016 inches), commonly used during the alignment phase, were tested. A three-point bending test was carried out to evaluate the load-deflection characteristics. The archwires were subjected to bending at a constant temperature of 37°C and deflections of 2 and 4 mm. Analysis of variance showed that thermal NiTi wires exerted significantly lower working forces than superelastic wires of the same size in all experimental tests (P < 0.05). Wire size had a significant effect on the forces produced: with an increase in archwire dimension, the released strength increased for both thermal and superelastic wires. Superelastic wires showed, at a deflection of 2 mm, narrow and steep hysteresis curves in comparison with the corresponding thermal wires, which presented a wide interval between loading and unloading forces. During unloading at 4 mm of deflection, all wires showed curves with a wider plateau when compared with 2 mm deflection. Such a difference for the superelastic wires was caused by the martensite stress induced at higher deformation levels. A comprehensive understanding of mechanical characteristics of orthodontic wires is essential and selection should be undertaken in accordance with the behaviour of the different wires. It is also necessary to take into account the biomechanics used. In low-friction mechanics, thermal NiTi wires are to be preferred to superelastic wires, during the alignment phase due to their lower working forces. In conventional straightwire mechanics, a low force archwire would be unable to overcome the resistance to sliding.

Influence of bracket-slot design on the forces released by superelastic nickel-titanium alignment wires in different deflection configurations.

OBJECTIVE To evaluate how different bracket-slot design characteristics affect the forces released by superelastic nickel-titanium (NiTi) alignment wires at different amounts of wire deflection. MATERIALS AND METHODS A three-bracket bending and a classic-three point bending testing apparatus were used to investigate the load-deflection properties of one superelastic 0.014-inch NiTi alignment wire in different experimental conditions. The selected NiTi archwire was tested in association with three bracket systems: (1) conventional twin brackets with a 0.018-inch slot, (2) a self-ligating bracket with a 0.018-inch slot, and (3) a self-ligating bracket with a 0.022-inch slot. Wire specimens were deflected at 2 mm and 4 mm. RESULTS Use of a 0.018-inch slot bracket system, in comparison with use of a 0.022-inch system, increases the force exerted by the superelastic NiTi wires at a 2-mm deflection. Use of a self-ligating bracket system increases the force released by NiTi wires in comparison with the conventional ligated bracket system. NiTi wires deflected to a different maximum deflection (2 mm and 4 mm) release different forces at the same unloading data point (1.5 mm). CONCLUSION Bracket design, type of experimental test, and amount of wire deflection significantly affected the amount of forces released by superelastic NiTi wires (P<.05). This phenomenon offers clinicians the possibility to manipulate the wires load during alignment.

Transglutaminase 2 up-regulation is associated with RANKL/OPG pathway in cultured HPDL cells and THP-1-differentiated macrophages

Recent evidence emphasized that transglutaminase 2 (TG2), a protein cross-linking enzyme, may play a role in the early phase of inflammation. High levels of TG2 have been associated with the constitutive activation of nuclear factor-kappa B (NF-κB) that is considered the main regulator of inflammation. In this context, the receptor activator of NF-kappa B ligand (RANKL) and receptor activator of NF-κB have extensive functions in the regulation of cytokine secretion associated with different pathological conditions. The human periodontal ligament (HPDL) cells, which express and secrete osteoprotegerin (OPG) and RANKL, represent an useful “ex vivo” model for monitoring cell response in inflammatory microenvironments, such as periodontitis-dependent tissue response. Thus, we evaluated TG2 expression and alterations in RANKL/OPG ratio occurring in cultured HPDL cells. The HPDL cells were obtained from patients with chronic periodontitis (CP) and healthy subjects. We observed the up-regulation of some inflammatory markers, such as IL-6, TNF-α, and HMGB-1, and at the same time an increase in TG2 mRNA levels in HPDL cells from CP patients compared with healthy subjects. We found a positive correlation between RANKL/OPG ratio and TG2 mRNA levels in HPDL cells from CP patients. In the parallel experiments, we demonstrated that TG2 inhibition reduced RANKL expression in both HPDL cells from CP patients and monocytes differentiated to macrophages by tetradecanoyl phorbol acetate treatment. Given the RANKL key role in NF-κB pathway and the observed up-regulation of pro-inflammatory cytokines, our data suggest that TG2 may be involved in molecular mechanisms of inflammatory response occurring in periodontal disease.

In vitro evaluation of resistance to sliding in self- ligating and conventional bracket systems during dental alignment

Objective To investigate the resistance to sliding (RS) in self-ligating and conventional ligation bracket systems at 5 different second-order bracket angulations by using low-stiffness alignment wires in a 3-bracket experimental model and to verify the performance of the main RS components in both systems when these wires are used. Methods Interactive self-ligating brackets with closed and open slides were used for the self-ligating (SL) and conventional ligation (CL) groups, respectively; elastomeric ligatures (1 mm inner diameter) were used in the latter system. The alignment wire used was 0.014 inch heat-activated NiTi (austenitic finish temperature set at 36℃ by the manufacturer). A custom-made testing machine was used to measure frictional resistance. Tests were repeated 5 times at every angulation simulated. All data were analyzed statistically. Results The RS increased significantly with increasing angulation in both SL and CL groups (p < 0.0001). However, the RS values were significantly higher at every angulation (p < 0.0001) in the CL group. Conclusions Despite the relevance of the binding phenomenon, ligation forces predominantly affect the RS when low-stiffness alignment wires are used.

Occlusal and MRI characterizations in systemic sclerosis patients: A prospective study from Southern Italian cohort

OBJECTIVES The aim of the present study was to assess the prevalence of temporomandibular joint (TMJ) symptoms, clinical and magnetic resonance imaging (MRI) findings in a cohort of Southern Italian patients with SSc. METHODS Twenty-seven patients with SSc (12 diffuse, 15 limited, mean age 53.9, SD±1.2) and 28 healthy subjects (mean age 54.8, SD±4.2) were enrolled in this observational cohort study. In all patients, clinical examination for assessing the presence of TMJ sounds, pain in the TMJ area, tenderness of masticatory muscles, limited mouth opening, pain assessment, MRI scan and Anamnestic and Dysfunctional Index were performed. RESULTS The test groups reported more clinical and MRI findings of TMJ symptoms and dysfunction than control group. The frequency distributions of symptoms were significantly different (P<0.05), in the test groups for TMJ sounds, pain during mandibular movement and difficulty in the maximum mouth opening. There was also a significant decrease (P<0.001), in the test groups, in the mean of leftward, rightward laterotrusion and protrusion. Correlation analysis allowed to affirm that maximum opening leftward laterotrusion, protrusion and click were significantly correlated to Modified Rodnan Skin Score. The mean duration of disease was significantly correlated, ever in total SSc group, only for the maximum mouth opening value. CONCLUSION This study demonstrates that TMJ involvement is common in SSc patients and is correlated with a length and involvement of disease and supports the notion that TMJ examination should be encouraged in the rheumatology setting and clinicians should provide a right pain management and patient support.

Combined orthodontic-surgical management of a transmigrated mandibular canine

The presence of an impacted mandibular canine is one of the most difficult challenges that an orthodontist will meet. Orthodontic treatment is planned on an individual basis after thoroughly considering the patients overall facial and dentoskeletal characteristics; the duration, risks, and costs of treatment; patient preferences; and the orthodontists experience. This article reports an orthodontic treatment of a boy, age 12.9 years, with an impacted mandibular canine in the permanent dentition that was successfully managed. Radiographic analysis indicated a transmigration of the mandibular right canine. The orthodontic treatment plan included extraction of the deciduous right canine followed by surgical exposure and ligation of the permanent canine. Eruption was properly guided, and the correct position of the tooth was achieved. This challenging treatment approach is described in detail, including the mechanics used to align the impacted canine.