Marco Migliorati

Miniscrew design and bone characteristics: an experimental study of primary stability.

INTRODUCTION The purpose of this study was to evaluate the correlations between bone characteristics, orthodontic miniscrew designs, and primary stability. METHODS Four different miniscrews were placed in pig ribs. The miniscrews were first scanned with a scanning electron microscope to obtain measurable images of their threads. Subsequently, the maximum insertion torque of the screws and the maximum load value in the pullout force tests were measured; furthermore, bone specimen characteristics were analyzed by using cone-beam computed tomography. For each bone sample, the insertion site cortical thickness as well as both cortical and marrow bone density were evaluated. The nonparametric Kendall rank correlation (tau) was used to evaluate the strength of the associations among the characteristics measured. The nonparametric Kruskall-Wallis test was used to evaluate the differences among the groups, and post-hoc comparisons were assessed by using the Nemenyi-Damico-Wolfe-Dunn test. RESULTS A significant dependence was found between pitch and maximum insertion torque (tau, -0.49). Positive correlations were also found between pullout force and maximum insertion torque (tau, 0.64), cortical thickness (tau, 0.36), and marrow bone density (tau, 0.35). CONCLUSIONS In this in-vitro experimental study, strong correlations were observed among miniscrew geometry, bone characteristics, and primary stability.

Block Allograft Technique versus Standard Guided Bone Regeneration: A Randomized Clinical Trial

PURPOSE The aim of this randomized clinical trial was to compare the potential of deproteinized bovine bone added to autologous bone or corticocancellous allograft block with or without the addition of recombinant human platelet-derived growth factor-BB (rhPDGF-BB) to regenerate mandibular atrophic ridges. MATERIALS AND METHODS TRIAL DESIGN parallel, allocation ratio of 1:1 using a split-mouth model. Eligibility criteria for patients: adult patients; bilateral atrophic edentulous areas in the posterior area of the mandible; a preoperatory cone beam computed tomography scan; and absence of systemic diseases affecting the bone metabolism. Bone graft intervention for control group consisted of bone chips collected with a scraper mixed with deproteinized bovine bone covered with a resorbable membrane. Bone graft intervention for test group consisted of a corticocancellous allograft block, shaped before surgery, and protected with a collagen membrane. In addition, both groups received rhPDGF-BB or a saline solution as control. As primary outcome quantity, bone variation after a 1-year healing period was considered. A p-value of.05 was considered statistically significant. RESULTS Sixteen patients were enrolled in this trial. A total of 50 implants and 32 bone grafts were placed. All patients concluded the study (no dropouts). Change at 1 year in bone volume was not significantly different between the two groups (p-value = .25). Effect of treatment in terms of change in bone volume at 1 year was not significant (p-value = .89) when saline solution was used while was at limit of significance when rhPDGF-BB was used (p-value = .052). After 1 year, all the implants were successfully integrated. CONCLUSIONS The block allograft and the standard regenerative procedure showed similar results in terms of regenerated bone volume after 1 year of functional loading. The rhPDGF-BB positively influenced soft-tissue healing.

Efficacy of professional hygiene and prophylaxis on preventing plaque increase in orthodontic patients with multibracket appliances: a systematic review.

BACKGROUND Plaque increase is a troubling side-effect of fixed orthodontic therapy. This generally arise as a consequence of long-term difficulty in maintaining adequate oral hygiene while wearing multibracket appliances. Demineralization, also known as white spot, causes particular concern as it spoils the aesthetic outcome of the treatment itself, not to mention the integrity of the enamel. OBJECTIVES To collate the existing literature by evaluating the efficacy of dental hygienist intervention on plaque increase in fixed orthodontics patients. MATERIALS AND METHODS A targeted search of the Medline database (Entrez PubMed), EMBASE, and CENTRAL using relevant Medical Subject Headings was performed. The articles selected were all published before June 2013 and comprised randomized clinical trials, prospective longitudinal controlled clinical trials, and before/after studies onto the plaque increase of fixed appliances. RESULTS The search strategy yielded 630 articles. Following the application of inclusion and exclusion criteria, 10 articles qualified for the final review. CONCLUSION The quality of the retrieved researches ranged from low (one study) to high (one study). Six controlled trials were considered at unknown risk of bias. Data showed that regular patient motivation sessions and mechanical tooth cleaning by a professional dental hygienist help maintaining good oral hygiene during fixed orthodontics.

Clinical association between teeth malocclusions, wrong posture and ocular convergence disorders: an epidemiological investigation on primary school children

BackgroundAs the various systems in the body are inter-connected to form a single structural unit, a pathological condition in one area can also affect other areas. There are many known correlations between the visual and motor system. The importance of visual function, particularly the paracentral peripheral field of view, in motor coordination, ambulation and the maintenance of balance has been amply demonstrated.In line with current medical principles, which are moving towards a more holistic view of the human body, this study aims to investigate, in an interdisciplinary manner, the incidence of dental malocclusions together with posture and eye convergence disorders.MethodsSix hundred and five children attending at the 3rd, 4th and 5th years of seven Genoa primary schools were examined. Each child underwent the following examinations: (i) dental/occlusal; (ii) orthoptic; and (iii) postural. Occlusal data concerned the presence of cross-bite, midline deviation with a mandibular shift, bad habits and deep or open bite.Postural assessment involved frontal and lateral inspection, investigation during trunk flexion and ambulation, and note of any asymmetry in the lower limbs. The recorded orthoptic data included those pertaining to ocular dominance, a cover test, convergence and the Brock string test.ResultsA prevalence of cases with an unphysiological gait was found in patients with overjet (14.70%) or overbite (14.87%), while the percentage of patients with normal occlusion that showed an unphysiological gait was 13.08%. Also, about 93.8%–94.2% of children showed normal legs without dysmetry, with no difference in respect to the type of occlusion. Subjects with an open bite or deep bite showed a slightly different distribution of right or left dominant eyes.ConclusionAbout 13% of children showed a pathological gait and, among them, vertical anomalies of occlusion (deep bite or open bite) were prevalent with respect to the other occlusal defects. The vertical dimension of occlusion revealed a slight relationship with the proper dominant eye. Postural, orthoptic, osteopathic and occlusal variables were often clinically associated, and therefore these disorders appear to request a multidisciplinary medical approach for their treatment.

Clinical and Aesthetic Outcome with Post-Extractive Implants with or without Soft Tissue Augmentation: A 2-Year Randomized Clinical Trial.

BACKGROUND The aesthetic outcome of an implant-supported restoration is first of all dependent on the soft tissue volume. Because the labial bone plate resorbs in every direction after tooth extraction, even when an implant is placed immediately, most patients end up with compromised aesthetics. MATERIALS AND METHODS In this parallel-designed, randomized clinical trial, participants were randomly assigned to the test group (immediate load post-extractive implant treated with subepithelial connective tissue graft placed using the tunnel technique in the labial area) and control group (immediate load post-extractive implant treated without raising a flap) with an allocation ratio of 1:1. Both groups received deproteinized bovine bone mineral. Patients were observed at baseline, crown insertion, 1-year follow-up, and 2-year follow-up. Clinical, radiological and aesthetic parameters were recorded to assess primary treatment outcomes. A random permuted block system was blindly generated ensuring uniformity of the patient allocation during the trial by randomly distributing three participants to the test and three participants to the control group every six treated patients. RESULTS At the 2-year examination, all 47 implants were successfully integrated, demonstrating stability and healthy peri-implant soft tissues as documented by standard clinical parameters. The results showed a soft tissue remodeling of -10% in thickness and -18% in highness in the non-grafted group, whereas in the grafted group there was a gain of 35% in thickness and a slight reduction of -11% in highness. Test group reported an increase of aesthetic result (mean pink aesthetic score [PES] 8) compared with control group (mean PES 6.65). CONCLUSIONS This prospective study demonstrates the effectiveness of placing a soft tissue graft at the time of immediate implant placement in the aesthetic zone. At the 2-year follow-up, test group revealed a better aesthetic outcomes and stable facial soft tissues compared with control group.

Impacted and transmigrant mandibular canines incidence, aetiology, and treatment: a systematic review.

Background The incidence of impacted and transmigrant mandibular canines in the mandible is not as high as that in the maxilla; consequently, it is more difficult to find clinical guidelines derived from sound studies based on large patient samples. Objectives The aim of this systematic review was to summarize currently available data pertaining to the incidence and aetiology of impacted and transmigrant mandibular canines and the success rates of different treatment strategies. Methods This review was registered with PROSPERO (CRD42014006175) and was conducted using PRISMA and CRD (Centre for Reviews and Dissemination, University of York) statement. A computerized search of studies published up to February 2016 was conducted using the following databases: PubMed, Cochrane Central Register of Controlled Clinical trials, ISI Web of Knowledge, and Scopus. To identify any relevant publications not included in this list, we manually searched the references lists of the selected articles. The Newcastle-Ottawa Scale quality assessment tool was utilized to classify the included articles. Results In total, 630 articles were identified after the removal of duplicates. A total of 13 studies published between 2001 and 2015 met all the eligibility criteria and were included for the final analysis. The sample size in these studies ranged from 14 to 112873 teeth, while their methodological quality ranged from low to medium. Conclusions According to the findings from our review, the incidence of canine impaction in the mandible ranges from 0.92 to 5.1 per cent, while that of canine transmigration ranges from 0.1 to 0.31 per cent. Various etiologies may play a role, including odontomes (up to 20 per cent) and lateral incisor anomalies (16 per cent). Surgical extraction (89 per cent in some studies) and orthodontic traction (20-32 per cent) are the most commonly used treatment strategies, with the latter showing a failure rate of 17 per cent in two studies.

Orthodontic miniscrews: an experimental campaign on primary stability and bone properties

OBJECTIVE To evaluate the primary stability of different shaped miniscrews through the acquisition of data regarding maximum insertion torque, pullout force, and a radiodiagnosic evaluation of bone characteristics. MATERIALS AND METHODS Sixty fresh porcine bone samples were scanned by computed tomography (CT) and cone-beam computed tomography (CBCT). By means of a dedicated software, CT and CBCT images were analysed to measure the insertion-site cortical thickness, cortical density, and marrow bone density. Sixty miniscrews of 12 different types were implanted with no predrilling pilot hole in the bone samples. Every device was tightened by means of a digital torque screwdriver and torque data were collected. Subsequently, pullout tests were performed. Spearman and Pearson correlations were employed to compare any relationship between continuous variables. RESULTS Different types of miniscrews did not show statistically significant differences in their torque value (P = 0.595), instead a significant difference was revealed by considering their load measures (P = 0.039). Cortical bone thickness resulted strongly correlated both with value of load (P < 0.001), and modestly with torque measures (P = 0.004). A strong positive correlation was found between CT and CBCT both for cortical density (P < 0.001) and marrow bone density (P < 0.001). CONCLUSION Bone characteristics play the major role in miniscrews primary stability.

Torque Loss After Miniscrew Placement: An In-Vitro Study Followed by a Clinical Trial.

To evaluate torque loss a week after insertion, both in an in vivo and an in vitro experimental setup were designed. In the in vivo setup a total of 29 miniscrews were placed in 20 patients who underwent orthodontic treatment. Maximum insertion torque (MIT) was evaluated at insertion time (T1). A week later, insertion torque was measured again by applying a quarter turn (T2); no load was applied on the screw during the first week. In the in vitro setup a total of 20 miniscrews were placed in pig rib bone samples. MIT was evaluated at insertion time (T1). Bone samples were kept in saline solution and controlled environment for a week during which the solution was refreshed every day. Afterwards, torque was measured again by applying a quarter turn (T2). The comparison of MIT over time was done calculating the percentage difference of the torque values between pre- and post-treatment and using the parametric two independent samples t-test or the non-parametric Mann–Whitney test. After a week unloaded miniscrews showed a mean loss of rotational torque of 36.3% and 40.9% in in vitro and in in vivo conditions, respectively. No statistical differences were found between the two different setups. Torque loss was observed after the first week in both study models; in vitro experimental setup provided a reliable study model for studying torque variation during the first week after insertion.

The impact of temporomandibular joint arthritis on functional disability and global health in patients with juvenile idiopathic arthritis

OBJECTIVES The objective of the study was to evaluate the impact of temporomandibular joint (TMJ) arthritis on the functional disability and quality of life in patients affected by juvenile idiopathic arthritis (JIA). MATERIALS AND METHODS Sixty-two consecutive patients with JIA with or without TMJ arthritis and 35 healthy control subjects were enrolled in the study. The demographic data, disease activity and clinical characteristics were obtained from all patients. The functional disability was assessed using the Italian version of the Childhood Health Assessment Questionnaire (C-HAQ). The oral health-related quality of life (OHRQoL) was assessed using the Child Perception Questionnaire (CPQ11-14). Possible determining factors of TMJ arthritis comprised demographic, disease characteristics and scores derived from questionnaires that were assessed by a uni and multivariable logistic regression analysis. RESULTS Compared with patients without TMJs arthritis, JIA patients with TMJ arthritis presented higher functional disability. The multivariable logistic regression analysis performed showed that female subjects (OR = 1.5, P = 0.041), with a JIA duration over 3.9 years (OR = 2.7, P = 0.033) and presenting higher C-HAQ and CPQ11-14 scores (OR = 2.7, P = 0.012 and OR = 2.9, P = 0.015, respectively) were the greatest determining factors for TMJ arthritis. CONCLUSIONS JIA patients with TMJ arthritis presented higher functional disability and lower OHRQoL scores compared with JIA patients without TMJ arthritis. TMJ arthritis was strongly associated with JIA duration and activity, especially in female patients.

On the stability efficiency of anchorage self-tapping screws: Ex vivo experiments on miniscrew implants used in orthodontics

BACKGROUND The clinical success of orthodontic miniscrews is strictly related to primary stability, which depends on bone viscoelastic properties too. In this study, we evaluated the short time mechanical response of native bone to miniscrews, by a laboratory test based on dynamic loading. METHODS Thirty-six segments of porcine ribs were first scanned by cone-beam computerized tomography to obtain insertion-site cortical thickness, cortical and marrow bone density. Twelve different types of miniscrews were implanted in the bone samples to evaluate the elastic compliance of the implants in response to a point force applied at the screw head normally to the screw axis. The compliance was measured dynamically in a Dynamic Mechanical Analysis apparatus as the Fourier Response Function between the signals of displacement and force. The measurements were repeated in five days successive to the insertion of the miniscrew. FINDINGS The elastic compliance was positively related to observation timepoints, but it was not related neither to the screw type nor to the value of the insertion torque. INTERPRETATION Stability behavior is significantly related to the short time response of native bone rather than to the screw design or the insertion torque values.