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Summary Objective To evaluate dental and skeletal effects of a new orthopaedic appliance for the treatment of Class III malocclusion in growing patients. Material and methods This retrospective cephalometric study was performed on a sample of 18 patients with a skeletal Class III malocclusion (4 males; 14 females; mean age 8.8 ± 1.5 years) treated with the Pushing Splints 3 (PS3) protocol. The control group consisted of 18 subjects (5 males; 13 females; mean age 9.1 ± 1.8 years) selected from a database of subjects with untreated Class III malocclusion. The cephalometric analysis was performed at the beginning (T0) and the end of the orthopaedic therapy (T1). Significant differences between the treated and control groups were assessed with independent samples t-test (P < 0.05). Results In the PS3 group, the post-treatment cephalometric values showed a forward displacement of the maxilla, resulting in a statistically significant increase of the SNA angle. ANPg and Wits appraisal improved significantly compared with the control group. Lingual inclination of mandibular incisors and buccal inclination of the upper incisors were significantly increased in comparison with the control group. No significant differences were recorded for backward mandibular rotation. Limitations This study presents a short-term evaluation of the treatment and the use of a historical control group. Conclusions The PS3 was effective for the treatment of Class III malocclusion in growing patients, with favourable maxillary advancement and control of the vertical skeletal relationships.

Objectives: To detect changes in mandibular growth between a historical group (HG) from the American Association of Orthodontics Foundation Craniofacial Growth Legacy Collection (AAOF Legacy) and a contemporary group (CG) of normodivergent or hypodivergent Class II untreated subjects. Setting and Sample Population.: The sample included radiographs from the AAOF Legacy and from the University of Naples ‘Federico II’ collected during a previous RCT. Materials & Methods: The HG was composed of 26 individuals (around 1960) from the AAOF Legacy (15 from theBurlington Growth Study, nine from the Oregon Growth Study and two from the Michigan Growth Study) who were matched by sex, age and race with the 26 individuals of the CG (around 2010). Two lateral cephalograms obtained at T0 and T1 (12 months) were selected, and one examiner performed the cephalometric measure‐ ments according to Pancherz's method. The normal distribution of data was confirmed by the Shapiro‐Wilk test, MANOVA analysis and t test for paired and unpaired data were performed. The level of significance was set according to Bonferroni's correction. Results: At T0 and T1, the between‐group comparisons revealed greater linear di‐ mensions for Maxillary base, Maxillary incisor and Mandibular incisor in the CG than in the HG (P ≤ 0.002). No significant difference was found in the growth rate for linear skeletal measurement between the HG and the CG. Conclusions: In this study, the cephalometric analysis showed larger maxillary dimen‐ sions for the CG than the HG, while no differences were shown between the growth rate and direction of the two groups.

Several orthopedic procedures have been used in early treatment to reduce the need for orthognathic surgery in skeletal Class III. The most used treatment is Rapid Maxillary Expansion and Facemask. This procedure also determines a clockwise rotation of the mandible, increasing the vertical dimensions of the lower third of the face. Therefore, the control of vertical dimension appears to be a key objective in Class III hyperdivergent patients. This article shows two skeletal Class III patients treated with a new appliance (Pushing Splints 3), that is able to correct sagittal discrepancy with a good control of the vertical growth. In both cases, Class I relationship with a proper Overjet and Overbite was achieved with improvement of profile. The final cephalometric values demonstrated a stable sagittal relationship and a good control of the vertical growth. The specific biomechanic features of the PS3 appliance permit the improvement of the sagittal jaw relationship, delivering at the same time vertical vectors that are able to control the alveolar and skeletal components of the vertical growth. This could be useful in the treatment of Class III hyperdivergent patients.

Objectives: The Frankel manoeuvre is a procedure by which the mandible of Class II individuals is postured forward in dental Class I relationship. The evaluation of the resulting facial profile provides information concerning the components determining the sagittal discrepancy. Data concerning the reproducibility of its assessment are not available. This study aimed to evaluate the intra-observer and inter-observer reproducibility of the assessment of the manoeuvre and to assess whether the amount of clinical experience affects its reproducibility. Methods: Two lateral photographs, one in centric occlusion, and the other with the mandible postured forward (Frankel manoeuvre) of 100 Angle Class II individuals aged between 9 and 13 years were evaluated by six orthodontists (T0). Each examiner was asked whether the facial profile worsen or not with the manoeuvre after being trained by an expert orthodontist. The test was repeated after 2 weeks interval (T1). Intra-observer and inter-observer agreement were evaluated by computing the Cohen’s K . Results: The agreement ( K values) between observations (T0 versus T1) for each examiner ranged from 0.49 to 0.72. The overall agreement was 0.65 [95% confidence interval (CI) = 0.54–0.75]. The agreement in the group with less clinical experience was 0.61 (95% CI = 0.46–0.76), while it was 0.68 (95% CI = 0.53–0.83) in the more experienced group. The amount of clinical experience did not affect intra-observer agreement ( P = 0.50). The overall agreement between the examiners and the trainer was 0.74 (95% CI = 0.65–0.83) and 0.73 (95% CI = 0.64–0.83) at T0 and T1 respectively. Conclusion: The assessment of the Frankel manoeuvre is reproducible and it is not influenced by the amount of clinical experience.

This Systematic Review (SR) aims to assess the quality of SRs and Meta-Analyses (MAs) on functional orthopaedic treatment of Class II malocclusion and to summarise and rate the reported effects. Electronic and manual searches were conducted until June 2014. SRs and MAs focusing on the effects of functional orthopaedic treatment of Class II malocclusion in growing patients were included. The methodological quality of the included papers was assessed using the AMSTAR (Assessment of Multiple Systematic Reviews). The design of the primary studies included in each SR was assessed with Level of Research Design scoring. The evidence of the main outcomes was summarised and rated according to a scale of statements. 14 SRs fulfilled the inclusion criteria. The appliances evaluated were as follows: Activator (2 studies), Twin Block (4 studies), headgear (3 studies), Herbst (2 studies), Jasper Jumper (1 study), Bionator (1 study) and Fränkel-2 (1 study). Four studies reviewed several functional appliances, as a group. The mean AMSTAR score was 6 (ranged 2-10). Six SRs included only controlled clinical trials (CCTs), three SRs included only randomised controlled trials (RCTs), four SRs included both CCTs and RCTs and one SR included also expert opinions. There was some evidence of reduction of the overjet, with different appliances except from headgear; there was some evidence of small maxillary growth restrain with Twin Block and headgear; there was some evidence of elongation of mandibular length, but the clinical relevance of this results is still questionable; there was insufficient evidence to determine an effect on soft tissues.

L’Organizzazione Mondiale della Sanità considera la salute orale come parte integrante, non solo dello stato di salute generale, ma anche della qualità della vita di ciascun individuo. In tale ottica, in accordo e con il sostegno del mondo professionale e della comunità scientifica di questo settore, le raccomandazioni cliniche in odontostomatologia contenute nel presente volume forniscono indicazioni e definiscono standard di intervento per la prevenzione e la cura delle più comuni patologie del cavo orale nonché per l’identificazione di percorsi terapeutici appropriati a supporto degli operatori pubblici e privati. Esse costituiscono, inoltre, uno strumento utile per mantenere alto il livello di qualità delle cure in questo periodo storico, nel quale, se da un lato crescono le opportunità tecniche di cura e la potenziale domanda delle stesse, dall’altro la riduzione delle risorse economiche a disposizione dei cittadini tende a limitare l’accesso all’offerta professionale privata e, al contempo, i processi di razionalizzazione dell’allocazione dei fondi nel SSN rendono più difficile l’accesso alle strutture pubbliche. L’individuazione di raccomandazioni cliniche chiaramente definite e rese pubbliche può facilitare la condivisione degli obiettivi e dei percorsi terapeutici tra odontoiatra e paziente, migliorare la comunicazione e, in ultima analisi, accrescere la fiducia sia nei riguardi del proprio specifico professionista che del “sistema delle cure” più in generale. La revisione delle “Raccomandazioni cliniche in odontostomatologia” si è resa necessaria in considerazione del cambiamento dell’evidenza scientifica, dell’immissione in commercio di nuovi materiali e dell’utilizzo di nuove tecnologie, specie in ambito protesico. Come per la precedente, alla realizzazione di questa edizione ha contribuito un ampio gruppo di docenti ed esperti delle singole branche odontoiatriche insieme alle più importanti e rappresentative Associazioni professionali e ai componenti della Commissione Albo Odontoiatri (CAO) nazionale.

Despite the growing demand for orthodontic care, a framework to support sustainable orthodontic decision-making is lacking, even if scientific literature offers several attempts to deal with this issue. As well known, dentistry generates solid health residues that include heavy metals and biomedical waste, that asks for a professional duty and a social responsibility of the orthodontist that should transform, more and more, his daily practice to a sustainable one, by adopting environmental oriented measures and, at the same time, cutting the overall costs of his professional performance while keeping the performance standards high. This work aims at filling such a gap in knowledge by proposing a decision tree algorithm that, besides increasing the level of agreement within and between orthodontists, allows for the adoption of a framework of sustainable orthodontic best practices, using a dataset of 290 randomly selected patients generated from 2011 medical records of patients of the orthodontic School at the University of Napoli “Federico II”. The best practices framework, provided as if-then rules which can be easily inspected by orthodontists, represents a sustainable model in that it minimizes the time and resources employed for dentistry decision-making, dramatically reduce the environmental impact in terms of waste and use of electric equipment and tools, and increases patient satisfaction by delivering quick and appropriate treatment, thus meeting the economic, environmental and social pillars of sustainability in health care.

To summarise the skeletal, dental and soft tissue effects of orthopaedic treatment on growing skeletal class III patients compared with a concurrent untreated similar control group and to evaluate whether the design of the primary studies may affect the results. A literature search was performed up to the end of February 2016. No restrictions were applied concerning language and appliances. Once the quality score was assessed, a meta-analysis was performed for the appliances used in more than three studies. A moderator analysis for study design was performed. The level of evidence was evaluated by means of the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) tool. The search resulted in 21 papers. The quality of most of the studies was medium. Each study reported skeletal sagittal improvement and overjet correction. Fourteen studies reported a significant increase in lower facial height. Follow-up data showed slight relapses in about 15% of patients. Meta-analyses were performed for the facemask and chin cup. The two appliances were efficient for correcting the sagittal discrepancy, increasing the divergence. In the analysis for study design, the retrospective studies showed a more efficient appliance than RCTs for 6 of 13 variables. The level of evidence was between very low and moderate. There is very low to low evidence that orthopaedic treatment is effective in the correction of Class III skeletal discrepancies and moderate evidence for the correction of the overjet. A common side effect is mandibular clockwise rotation in older subjects.

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

The aim was to assess the quality and to summarise the findings of the Systematic Reviews (SRs) and Meta-Analyses (MAs) on the dental and skeletal effects of maxillary expansion. Electronic and manual searches have been independently conducted by two investigators, up to February 2015. SRs and MAs on the dentoalveolar and skeletal effects of fixed expanders were included. The methodological quality was assessed using the AMSTAR (A Measurement Tool to Assess Systematic Reviews). The design of the primary studies included in each SR/MA was assessed with the LRD (Level of Research Design scoring). The evidence for each outcome was rated applying a pre-determined scale. Twelve SRs/MAs were included. The AMSTAR scores ranged from 4 to 10. Two SRs/MAs included only RCTs. The current findings from SRs/MAs support with high evidence a significant increase in the short-term of maxillary dentoalveolar transversal dimensions after Rapid Maxillary Expansion (RME). The same effect is reported with moderate evidence after Slow Maxillary Expansion (SME). However, there is moderate evidence of a non-significant difference between the two expansion modalities concerning the short-term dentoalveolar effects. With both RME and SME, significant increase of skeletal transversal dimension in the short-term is reported, and the skeletal expansion is always smaller than the dentoalveolar. Even though dental relapse to some extent is present, long-term results of the dentoalveolar effects show an increase of the transversal dimension, supported by moderate evidence for RME and low evidence for SME. Skeletal long-term effects are reported only with RME, supported by very low evidence.

Among different malocclusions, posterior cross-bite is thought to have a strong impact on the correct functioning of the masticatory system. The association between unilateral posterior cross-bite (UPCB) and temporomandibular joint (TMJ) clicking, however, remains still controversial. The aim of this study was to investigate whether the presence of UCPB during early adolescence increases the risk of reporting TMJ clicking after a long-term follow-up. A longitudinal survey design was carried out in a group of 12-year-old young adolescents, who were examined at baseline for TMJ clicking sounds and unilateral posterior cross-bite. After 10 years, 519 subjects could be reached by a telephone survey. Standardised questions were used to collect self-reported TMJ sounds and to determine whether participants had received an orthodontic treatment. Logistic regression analysis revealed a significant association between unilateral posterior cross-bite and subjectively reported TMJ clicking (odds ratio = 6·0; 95% confidence limits = 3·4-10·8; P < 0·0001). The incidence of TMJ clicking was 12%. At a ten-year follow-up, self-reports of TMJ clicking were significantly associated with the presence of UPCB at baseline, but not with the report of having received an orthodontic treatment. Within the limitation of this study, the presence of unilateral posterior cross-bite in young adolescents may increase the risk of reporting TMJ sounds at a 10-year follow-up. The provision of an orthodontic treatment, however, does not appear to reduce the risk of reporting TMJ sounds.

It has been suggested that malocclusions may influence whole body posture, including leg length, but the current scientific evidence to support this statement is poor. The aim of the present study was to investigate a possible association between leg length inequality (LLI) and unilateral posterior crossbite. A survey was carried out in young adolescents recruited from three schools. The sample included 1,159 subjects (633 males and 526 females) with a mean age of 12.3 years (range 10.1-16.1 years), who underwent an orthodontic and orthopaedic examination performed independently by orthodontists and orthopaedists. The data were analysed by means of logistic regression analysis. One hundred and twenty subjects (10.3 per cent) were diagnosed as having LLI. A unilateral posterior crossbite was found in 142 of the 1,159 subjects (12.2 per cent). Logistic multiple regression analysis, controlling for potential confounding variables, failed to reveal a significant association between LLI and unilateral posterior crossbite (odds ratio = 1.0, confidence limits = 0.6-1.9). A unilateral posterior crossbite does not appear to be associated with LLI, at least in young adolescents.

SUMMARY The aim of this work was to investigate the stability of the bracket – adhesive – enamel interface, as a function of adhesive material and of debonding procedure, in order to assess which debonding technique is the least detrimental to the enamel. Ninety lower adult bovine incisors were selected and metallic orthodontic brackets were bonded using three adhesive systems: Concise, Transbond, and Fuji Ortho. Three different debonding procedures were used based on tensile, shear, and torsional stresses. One-way analysis of variance statistical analysis was employed to compare mechanical properties, while the adhesive remnant index was used to evaluate fracture properties. Each adhesive material used showed a statistical difference in tensile failure. The difference between shear and torsion failure loads was statistically signifi cant only for the Fuji GC sample ( P < 0.01). The shear test was the most damaging to the enamel surface. Transbond luting resulted in greater adhesion than the Concise or Fuji Ortho systems. Fuji Ortho was more prone to accidental debonding, while Transbond tended to cause enamel lesions, since high loads were required to debond the bracket. Of the three modes examined, torsional debonding stress resulted in the least enamel damage.

AIMS: To investigate the effects of the application of an acute alteration of the occlusion (ie, interference) on the habitual masseter electromyographic (EMG) activity of females with temporomandibular disorders (TMD)-related muscular pain during wakefulness. METHODS: Seven female volunteers with masticatory myofascial pain participated in a crossover randomized clinical trial. Gold foils were glued on an occlusal contact area (active occlusal interference, AI) or on the vestibular surface of the same molar (dummy interference, DI) and left for 8 days. The masseter electromyogram was recorded during wakefulness in the natural environment by portable recorders under interference-free, dummy-interference, and active-interference conditions. The number, amplitude, and duration of EMG signal fractions with amplitudes above 10% of the maximum voluntary contraction (activity periods, APs) were computed in all experimental conditions. Muscle pain, headache, and perceived stress were each assessed with a visual analog scale (VAS), and an algometer was used to assess masseter and temporalis pressure pain thresholds. Data were analyzed by means of analysis of variance. RESULTS: The frequency and duration of the recorded APs did not differ significantly between the experimental conditions (P>.05), but a small and significant reduction of the EMG mean amplitude of the APs occurred with AI (P.05). CONCLUSION: An active occlusal interference in female volunteers with masticatory muscle pain had little influence on the masseter EMG activity pattern during wakefulness and did not affect the pressure tenderness of the masseter and temporalis.

The aim of this study was to test the hypothesis that unilateral posterior crossbite influences postural stability of the whole body. Twenty-six subjects (14 males and 12 females) affected with unilateral posterior crossbite were selected and compared with 52 controls matched for age and gender. Postural stability was assessed using a stabilometric platform. The following stabilometric measurements were assessed: weight distribution on foot area and speed of body sway. Tests were performed under two occlusal conditions: teeth in intercuspal position (ICP) and while keeping two cotton rolls between teeth without clenching. The weight distribution on foot area and the speed of body sway were not significantly influenced from crossbite (with and without lateral mandibular slide), occlusal conditions (ICP, cotton rolls), and gender. Therefore, the treatment of this malocclusion in order to prevent or to treat postural disorders is not justified.

The aim of the study was to compare neuromuscular features of the masseter muscle in subjects with different vertical craniofacial morphology. Fifteen short-faced (mandibular plane-Frankfurt plane angle or = 23 degrees) male students participated. The thickness of the masseter was assessed by ultrasonography. Onset and endurance of exercise pain were recorded during sustained biting at a level of 15% of maximum voluntary contraction and 30 micro V electromyographic activity. Pain and fatigue was measured on visual analog scales before and after the biting, as well as before and after 10 min chewing. Statistical comparison showed that the masseter muscle was significantly thicker (+15%) in the short-faced than the normal- to long-faced subjects. The pain onset time and endurance time were also consistently shorter in short-faced subjects, whereas the intensity of pain and fatigue did not differ significantly between the two groups. Multiple stepwise regression showed positive influence from the mandibular plane inclination and the masseter thickness on the pain onset time and endurance time. The present findings support the concept that subjects with different craniofacial morphology show neuromuscular differences.

The aim of this study was to investigate the relationship between the curve of Spee and skeletal facial morphology. Dental casts and lateral cephalograms were obtained from 59 orthodontic patients. The amount of concavity of the curve of Spee was calculated by a second-order quadratic interpolation of buccal cusp tips obtained from lateral digital photographs of the teeth. The cephalometric analysis aimed to evaluate the sagittal and vertical craniofacial dimensions as well as the position of the mandibular condyle with respect to the occlusal plane. These variables, included in a multiple regression model, could explain 34% of the total variance of the curve of Spee. The amount of the curvature was significantly related to (a) the horizontal position of the condyle with respect to the dentition, (b) the sagittal position of the mandible with respect to the anterior cranial base, and (c) the ratio between the posterior and anterior facial height. No significant relationship was found between the curve of Spee and any of the other cephalometric variables. The curve of Spee was not influenced by age and gender of the subjects investigated.

Although the cardiovascular effects of exercise have been extensively investigated in man, little attention has been paid to such responses to jaw muscle activity. The aim here was to investigate the general cardiovascular effects of chewing activity in a single-blind, cross-over design. Ten healthy individuals performed one of the following chewing tasks in four separate sessions: chewing a very hard gum, chewing a moderately hard gum, chewing a soft gum, and "empty chewing" without a bolus. Unilateral chewing of gum or empty chewing was performed for 20 min on the participant's most convenient chewing side at a constant rate of 80 cycles/min. In each session, heart rate and arterial blood pressure were recorded together with electromyographic activity in the masseter and anterior temporalis muscles on the chewing side. Ratings of perceived masticatory fatigue were recorded with visual analogue scales. The heart rate and blood pressure were significantly increased (ANOVA; p < or= 0.01) during the chewing tasks and the increases were, in parallel with the muscle activity, more pronounced the harder the gum. With the very hard gum, heart rate increased by up to 11 beats/min, the systolic blood pressure was 14 mmHg (1.9kPa) higher, and the diastolic blood pressure was 11 mmHg (1.5kPa) higher. The perceived fatigue was proportional to the level of muscle activity. After 10 min of recovery from exercise, heart rate and arterial blood pressures were slightly but still significantly elevated. The results demonstrate that chewing is associated with general circulatory effects proportional to the bolus resistance.

This study compared the efficacy and efficiency of two professional prophylaxis procedures in orthodontic patients performing different oral hygiene regimens: the air powder polishing system (APP), and the rubber cup and pumice (RCP) technique. Sixty-two patients were divided into two groups: group I included 40 subjects who did not use any chlorhexidine mouthwash and group II comprised 22 subjects who regularly rinsed with a chlorhexidine mouthwash (at a 0.12 per cent concentration) and showed increased tooth staining. Using a split-mouth experimental design, the buccal and lingual tooth surfaces were cleaned in half of the mouth by the APP and in the opposite half by the RCP technique. Tooth surfaces were scored before (PRE) and after (POST) the experimental procedures for the plaque index (PI), and for the presence of tooth staining. In addition, the treatment time required by each procedure was recorded. In test group I, significant reductions in the PI after APP and RCP were observed. Likewise, in test group II, both procedures significantly reduced the baseline PI values. In both experimental groups, the percentage of stained sites significantly decreased after APP and RCP, but in test group II, APP seemed to be more effective than RCP. In addition, APP required significantly less time than RCP to remove dental plaque and staining. These data show that both professional prophylaxis procedures are effective in orthodontic patients, with APP being the most time-efficient technique and the most effective method for removal of tooth staining.

Myogenous pain is frequently associated with tenderness of the involved muscle. One way of quantifying tenderness is to evaluate pressure pain thresholds [PPTs]. Pressure pain threshold meausurements, however, show marked inter-individual and intra-individual variations. We designed a series of experiments to investigate the effects of several factors on PPT threshold variations in human jaw muscle [masseter and temporalis] in healthy subjects and patients with myogenous pain. Short-term and long-term reliability of pressure algometry were evaluated in normal subjects; the inter-individual variability was found to be much higher than the intra-individual variability, a result suggesting that pressure algometers are particularly indicated for longitudinal within-subject design studies. A non-experimental emotional stressor [a difficult pre-graduate examination] in healthy subjects was found to decrease the mechanical pain thresholds of the masticatory muscles, The ovarian cycle in healthy fertile women also influenced muscle sensitivity, with PPTs being significantly lower in the periovulatory phase. Prolonged chewing activity in normal subjects did not modify pain thresholds, a result indicating that jaw muscles are extremely resistant to fatigue induced by prolonged dynamic contractions. In contrast, static endurance tasks [sustained bilateral biting at 7.5, 10, 15, 25 and 40% of the maximal voluntary contraction on bite force transducers in the molar regions until exhaustion] in healthy subjects significantly decreased PPTs. Short-term periodontal pain [provoked in healthy subjects by inserting orthodontic separators] significantly reduced PPTs. Pressure pain thresholds of jaw muscles in female myogenous patients [i.e., affected with myofascial pain] were significantly lower than in control subjects. In conclusion, in healthy subjects psychological stress, masticatory activity, heterotopic pain and ovarian cycle can affect PPT of the masseter and termporalis muscles, however, the contribution of each factor to the variations of PPT range from 0 to 25% at the most. These values are far below the differences in percentage found between muscle pain patients and control subjects [4-50%].

Hyperdontia is a disorder of odontogenesis characterised by excess teeth. Many complications can be associated with supernumerary teeth, such as crowding, tooth displacement, diastema, deep caries, retention or impaction, delayed eruption or ectopic eruption of adjacent teeth, aesthetic problems, neuralgic manifestations, root resorption of adjacent teeth, and dentigerous cyst formation with significant bone destruction. Treatment of hyperdontia depends on the area and number of supernumerary teeth, and also on the presence of pathologic processes that can affect them and/or the teeth of the normal series that could be erupted, retained or impacted.The present case report describes the clinical management of two impacted supernumerary teeth, which impeded the eruption of the maxillary right central incisor in a paediatric patient. A multidisciplinary treatment approach was planned, including the surgical removal of the supernumerary teeth and the orthodontic correction of the unerupted permanent maxillary right central incisor. Combined surgical and orthodontic treatment resulted in an aesthetically pleasant and balanced occlusion. Thus, early multidisciplinary treatment is required for greater hard and soft tissue preservation.

In 1989, the ERASMUS Bureau of the European Cultural Foundation of the Commission of the European Communities funded the development of a new 3-year curriculum for postgraduate education in orthodontics. The new curriculum was created by directors for orthodontic education representing 15 European countries. The curriculum entitled 'Three years Postgraduate Programme in Orthodontics: the Final Report of the Erasmus Project' was published 1992. In 2012, the 'Network of Erasmus Based European Orthodontic Programmes' developed and approved an updated version of the guidelines. The core programme consists of eight sections: general biological and medical subjects; basic orthodontic subjects; general orthodontic subjects; orthodontic techniques; interdisciplinary subjects; management of health and safety; practice management, administration, and ethics; extramural educational activities. The programme goals and objectives are described and the competencies to be reached are outlined. These guidelines may serve as a baseline for programme development and quality assessment for postgraduate programme directors, national associations, and governmental bodies and could assist future residents when selecting a postgraduate programme.

Statement of problem. The determination of a correct vertical dimension of occlusion is a critical procedure in clinical dentistry. Purpose. The objectives of this study were to analyze the relation between mandibular rest position and electrical activity of masticatory muscles and to compare clinical and electromyographic rest position in subjects with different vertical facial morphologic features. Material and methods. Clinical rest position and electromyographic rest position were investigated in 40 subjects. Electromyographic rest position ranged from 0.4 to 12.7 mm (average 7.7 +/- 2.7 mm). Clinical rest position ranged from 0.1 to 4.4 mm (average 1.4 +/- 1.1 mm). The average difference between electromyographic rest position and clinical rest position nas 6.3 +/- 2.5 mm (range 0.3 to 10.3 mm). Sixteen subjects were selected according to the Frankfort mandibular plane angle anti separated in two groups with the first group (eight subjects) having a mandibular plane angle less than or equal to 20 degrees and the second group having a mandibular plane angle 128 degrees. Results. Rest position was significantly greater (P < 0.05) in the low-angle group (2 +/- 1.3 mm) than in the high-angle group (0.8 +/- 0.8 mm). Electromyographic rest position did not differ between subjects with different facial morphologic features (8.1 +/- 1.7 mm low-angle group; 7.6 +/- 4.1 mm high-angle group. By varying the vertical dimension millimeter by millimeter, masseter and anterior temporal electromyographic activity demonstrated a considerable decrease over an interocclusal distance of 3 to 4 mm. Further mandibular opening up to 18 mm corresponded to small changes in postural activity. Conclusion. This study suggests that a jan pasture with a few millimeters of interocclusal distance involves a great reduction of masticatory muscle activity.

Structured Abstract Objectives The efficacy of functional appliances remains highly debated. This randomized controlled trial investigated the skeletal and dentoalveolar effects determined by the Sander bite-jumping appliance (BJA). The null hypothesis to be tested was that the appliance would not induce supplementary mandibular growth compared to untreated controls. Setting and Sample Population This study was carried out at the Section of Orthodontics, University of Naples Federico II, Italy. Forty-six patients receiving a clinical diagnosis of skeletal and dental class II due to mandibular retrusion were either allocated to a treatment (23 patients;15 boys, 8 girls; mean age ± SD: 10.9 ± 1.3 years) or to an untreated control group (23 patients;11 boys, 12 girls; mean age ± SD: 10.5 ± 1.2 years), by using a balanced block randomization. Methods Lateral cephalograms were taken before and after treatment and used for comparisons. Measurements were analyzed by descriptive statistics, univariate and multivariate statistical tests. Results Treated individuals had a significant increase in mandibular length (6.4 ± 2.3 vs. 3.5 ± 2.5 mm; p

Nous avons traite un groupe de 28 patients presentant des Classes II, avec une technique Bioprogressive modifiee ; pour la correction du rapport sagittal, nous avons utilise exclusivement des elastiques intermaxillaires. Les modifications dues a la croissance et au traitement mis en œuvre ont ete confrontees avec celles d'un groupe de controle comprenant 21 sujets, presentant la meme malocclusion, une typologie semblable, une distribution superposable des âges et des sexes mais n'ayant recu aucun traitement.Cette comparaison montre un effet orthopedique modeste de l'action des elastiques, la conservation de la direction de croissance, qui etait celle du sujet avant traitement et un bon controle de l'orientation du plan occlusal.

Orthodontic thermoelastic archwires produce lighter and more biologic forces than superelastic archwires and could therefore offer the possibility of reducing initial orthodontic pain. Nevertheless, evidence concerning this issue is scarce. The aim of this study was to compare pain perception following first archwire placement in patients with thermal heat-activated (HANT) and superelastic (SE) nickel-titanium archwires.Thirty subjects (11 males, 19 females; range, 11 to 26 years of age) were recruited. Metal brackets were bonded in the maxillary or mandibular arch. Round 0.016-inch HANT or 0.016-inch SE archwires were randomly placed and tied with elastic ligatures. Each patient was invited to score tooth pain for 7 days at different time points (8:00, 12:00, 16:00, 20:00, and 24:00) using the visual analog scale (VAS).In both groups, pain was highest at day 2 and lowest at day 7. Patients with HANT archwires had significantly lower VAS scores (P.005) at days 2, 3, and 4 than subjects with SE archwires. This was also the case after adjusting for analgesic consumption, sports practicing, overlapping pain of different origin, and the concomitance of stressful events. The frequency of analgesic consumption was higher in the SE than in HANT group at day 3 (P.05). No differences in pain perception were found between time points, nor was any correlation found between dental crowding and pain. No difference in pain perception was found between the maxillary and mandibular dental arches.Initial orthodontic pain is reduced when using HANT orthodontic archwires.

Objective: To compare the surface roughness of different orthodontic archwires. Materials and Methods: Four nickel-titanium wires (Sentalloy®, Sentalloy® High Aesthetic, Titanium Memory ThermaTi Lite®, and Titanium Memory Esthetic®), three β-titanium wires (TMA®, Colored TMA®, and Beta Titanium®), and one stainless-steel wire (Stainless Steel®) were considered for this study. Three samples for each wire were analyzed by atomic force microscopy (AFM). Three-dimensional images were processed using Gwiddion software, and the roughness average (Ra), the root mean square (Rms), and the maximum height (Mh) values of the scanned surface profile were recorded. Statistical analysis was performed by one-way analysis of variance (ANOVA) followed by Tukey's post hoc test (P < .05). Results: The Ra, Rms, and Mh values were expressed as the mean ± standard deviation. Among as-received archwires, the Stainless Steel (Ra = 36.6 ± 5.8; Rms = 48 ± 7.7; Mh = 328.1 ± 64) archwire was less rough than the others (ANOVA, P < .05). The Sentalloy High Aesthetic was the roughest (Ra = 133.5 ± 10.8; Rms = 165.8 ± 9.8; Mh = 949.6 ± 192.1) of the archwires. Conclusions: The surface quality of the wires investigated differed significantly. Ion implantation effectively reduced the roughness of TMA. Moreover, Teflon®-coated Titanium Memory Esthetic was less rough than was ion-implanted Sentalloy High Aesthetic.

Orthodontic treatment is strongly dependent on the loads developed by metal wires, and the choice of an orthodontic archwire should be based on its mechanical performance. The desire of both orthodontists and engineers would be to predict the mechanical behavior of archwires. To this aim, Gum Metal (Toyota Central R&L Labs., Inc.), TMA (ORMCO), 35°C Copper NiTi (SDS ORMCO), Thermalloy Plus (Rocky Mountain), Nitinol SE (3M Unitek), and NiTi (SDS ORMCO) were tested according to dynamic mechanical analysis and differential scanning calorimetry. A model was also developed to predict the elastic modulus of superelastic wires. Results from experimental tests have highlighted that superelastic wires are very sensitive to temperature variations occurring in the oral environment, while the proposed model seems to be reliable to predict the Young’s modulus allowing to correlate calorimetric and mechanical data. Furthermore, Gum Metal wire behaves as an elastic material with a very low Young’s modulus, and it can be particularly useful for the initial stage of orthodontic treatments.

The relationship between posterior dentoalveolar heights and craniofacial vertical pattern has been matter of debate. Increased posterior dentoalveolar heights have been reported to be present in long face subjects, while in few studies the amount of molar dentoalveolar heights was negatively influenced by the divergence of the jaws. This, in turn, was interpreted as a dentoalveolar compensatory mechanism by which the teeth and the alveolar process adapt to jaw relationship in order to maintain a functional occlusion. Although this dentoalveolar compensatory mechanism has been reported to be present in adults and in subjects with permanent dentition, currently it is not known whether it might occur also in an early phase of growth, i.e. before growth spurts. In this study we tested the hypothesis that a dentoalveolar compensatory mechanism is absent in children with still unexpressed vertical growth potential.Cephalometric measurements obtained from 79 children younger than 9 were entered as independent variables in a multiple regression model. Maxillary and mandibular molar dentoalveolar heights were entered as dependent variables.Approximately 54% of the total variability was explained by the variability in anterior lower facial height (ANS-Me) and mandibular palatal plane angle (PP-MP). Both maxillary and mandibular molar dentoalveolar heights were significantly influenced by the length of the anterior lower facial heights as measured by ANSMe, and by the mandibulopalatal plane angle (PP-MP). Increases of ANS-Me and PP-MP had opposite effects on the amount of molar dentoalveolar heights.The findings suggest that an inverse relationship between posterior dentoalveolar heights and jaw divergence is already present when the vertical growth is stil incomplete.

Objectives The aims of this study were to evaluate the cytotoxicity of four orthodontic primers, including two hydrophilic and two hydrophobic materials, and to investigate the role of the reactive oxygen species (ROS) in induced cell damage. Moreover, the effects of the anti-oxidant N-acetyl cysteine (NAC) on primers toxicity was analyzed. Methods Human gingival fibroblasts (HGF) were exposed to different concentrations of primers (0–0.25 mg/ml) in the presence or absence of NAC, and the cytotoxicity was assessed by the MTT assay, while cell death was quantified by flow cytometry after propidium iodide staining. The increase in the induced ROS levels was detected by flow cytometry measuring the fluorescence of the oxidation-sensitive dye 2′,7′-dichlorofluorescein diacetate (DCFH-DA). Results All materials decreased cell viability in a dose-related manner after a 24 h exposure period. Cytotoxicity of orthodontic primers based on concentrations which caused a 50% decrease in cell viability (TC50) in HGF was ranked as follows (median values): Eagle Fluorsure (0.078 mg/ml) > Transbond XT (0.081 mg/ml) > Transbond MIP (0.128 mg/ml) > Ortho solo (0.130 mg/ml). Moreover, in HGF cells, all materials induced a dose-dependent increase in ROS levels compared to untreated cells. Incubation of HGF with NAC significantly reduced ROS production and decreased the cell damage and cytotoxicity caused by all materials tested (p Significance Our results suggested that hydrophilic primers were less cytotoxic than hydrophobic materials. Moreover, we demonstrated a major role of ROS in the induction of cell death since the antioxidant N-acetyl cysteine was able to prevent cell damage induced by all materials tested.

SUMMARY The aim of this research was to investigate the retention of a bracket equipped with a novel base, the R-system®. The design of the bracket base is characterized by concentric grooves. The behaviour of this bracket was compared with a bracket with a conventional mesh base from the same manufacturer. Thirty lower adult bovine incisors were selected and metallic brackets were bonded using the Concise adhesive system. Each bracket–adhesive–enamel interface was investigated according to torsion debonding. One-way analysis of variance was used for statistical evaluation. Finite element analysis was also undertaken. In order to assess if the technique was detrimental to the enamel, the mode of failure was determined using the Adhesive Remnant Index (ARI). The debonded surfaces were analysed using scanning electron microscopy (SEM) and electron dispersion spectrometry (EDS). The R-system® provided a bond strength greater than that of the mesh-base bracket. EDS showed that the amount of calcium on the novel base was higher than that on the conventional base, which allowed transfer of torsional stress more uniformly to the substrate, resulting in higher bond values for the R-system®. On the other hand, as debonding of the R-system® occurred at the enamel–composite interface, lesions to the enamel substrate are possible.

Randomised controlled trials (RCT) are considered the best source of scientific evidence--the gold standard--when evaluating the efficacy of orthodontic treatments. Frequently, RCT are planned as multicentre trials, with the intention of increasing statistical power and raising the precision of outcome estimates. The management of large-scale RCT, however, requires even more thorough organisation than conventional RCT. Indeed, the need for high accuracy and standardisation in data collection, research aids, secretarial skills, staff and patient training, and organisational meetings, make these studies time-consuming, expensive and, in general, relatively complex to carry out well. A website was developed to support a large scale-orthodontic RCT which aimed to evaluate the efficacy of a functional appliance(www.ortodonzia.unina.it). Websites such as this can increase the quality of data collection, simplify the randomisation process, speed up data collection, and improve trial monitoring. Web-based RCT have the potential to help globalise orthodontic research and also increase our rate of acquisition of evidence in orthodontics.

SUMMARY Orthodontic treatment is mainly dependent on the loads developed by metal wires. The load developed by a buckled orthodontic wire is of great concern for molar distalization and cannot be simply derived from mechanical properties measured through classical tests (i.e. tensile, torsion, and bending). A novel testing method, based on the Eulerian approach of a simple supported beam, has been developed in order to measure the load due to buckling of orthodontic wires. Elastic titanium molybdenum alloy (TMA; SDS Ormco) and superelastic Nitinol (3M Unitek) and copper nickel – titanium (NiTi; SDS Ormco) wires, each having a rectangular cross section of 0.016 × 0.022 square inches (0.41 × 0.56 mm 2 ), were used. The wires were activated and deactivated by loading and unloading. In order to analyse thermo-mechanical properties in buckling, mechanical tests were assisted by calorimetric measurements through differential scanning calorimetry (DSC). Statistical analysis to determine differences between the samples was undertaken using two-way analysis of variance (ANOVA) and Tukey’s post hoc test, and one-way ANOVA to assess differences between the tested wires under similar conditions and different materials. The results suggest that the load due to buckling depends on material composition, wire length, the amount of activation, temperature, and deformation rate. The results can be considered as the lower bound for the loads experienced by teeth as far as a buckled wire is concerned. At a temperature higher than the austenite fi nish transition temperature, superelastic wires were strongly dependent on temperature and deformation rate. The effect due to an increase of deformation rate was similar to that of a decrease of temperature. Load variations due to temperature of a superelastic wire with a length of 20 mm were estimated to be approximately 4 g/°C. The high performance of an applied superelastic wire may be related to the high dynamics of the load in relation to temperature.

Unilateral posterior crossbite has been considered as a risk factor for temporomandibular joint clicking, with conflicting findings. The aim of this study was to investigate a possible association between unilateral posterior crossbite and temporomandibular disk displacement with reduction, by means of a survey carried out in young adolescents recruited from three schools. The sample included 1291 participants (708 males and 583 females) with a mean age of 12.3 yrs (range, 10.1–16.1 yrs), who underwent an orthodontic and functional examination performed by two independent examiners. Unilateral posterior crossbite was found in 157 participants (12.2%). Fifty-three participants (4.1%) were diagnosed as having disk displacement with reduction. Logistic regression analysis failed to reveal a significant association between unilateral posterior crossbite and disk displacement with reduction (odds ratio = 1.3; confidence limits = 0.6–2.9). Posterior unilateral crossbite does not appear to be a risk factor for temporomandibular joint clicking, at least in young adolescents.

Publisher Summary An artificial Neural Network (NN) is a computational model of the human brain that assumes that computation is distributed over several simple interconnected processing elements, called neurons or nodes, which operate in parallel. This chapter illustrates the application of an intelligent computation approach to the support of the clinical decision-making on orthodontic extractions. Artificial neural networks trained using cephalometric and orthodontic cast measurements can provide a valuable support in the extraction therapeutical option in orthodontics. The chapter illustrates that neural network based decision-making support systems may be trained on the basis of clinical data and can be used where “rule based” decision making is unreliable or impossible. Therefore, neural network systems may become an important decision making support tool in orthodontics and find applications both in improving the clinical treatment and in maximizing the cost benefit of the treatment.

To compare the short-term efficacy of patient education only versus the combination of patient education and home exercises for the treatment of myofascial pain of the jaw muscles.Seventy myogenous temporomandibular disorder patients were assigned to 2 treatment groups. One group received patient education supplemented by general information about self-care of the jaw musculature. The other group received both education and a home physical therapy program. Treatment contrast, calculated from the mean normalized relative changes in anamnestic and clinical scores, was used to determine treatment success. Clinical outcome measures included pressure pain threshold (PPT) of the masseter, anterior temporalis, and Achilles tendon; pain-free maximal jaw opening; and pain on chewing, spontaneous muscle pain, and headache as rated on visual analog scales.After 3 months the success rate was 57% for the group that received education only and 77% for the group that received both education and home physical therapy (P = .157). The patients were then redivided into 2 groups: successfully treated patients and unsuccessfully treated patients. In the unsuccessfully treated group, pain-free maximal jaw opening increased significantly more among those who had been in the education and physical therapy group than among those who had been in the education-only group (P = .019). The change in PPT was significantly greater in successfully treated patients than in unsuccessfully treated patients (.009P.039), independent of the treatment modality, with higher PPTs among successful patients. There were no significant differences between the successfully and unsuccessfully treated groups or between treatment modalities for any other variable.Over a period of 3 months, the combination of education and a home physical therapy regimen, as used in this protocol, is slightly more clinically effective than education alone for the treatment of myofascial pain of the jaw muscles.

The aim of the study was to compare neuromuscular features of the masseter muscle in subjects with different vertical craniofacial morphology. Fifteen short-faced (mandibular plane-Frankfurt plane angle15 degrees) and 15 normal- to long-faced (mandibular plane-Frankfurt plane angleor = 23 degrees) male students participated. The thickness of the masseter was assessed by ultrasonography. Onset and endurance of exercise pain were recorded during sustained biting at a level of 15% of maximum voluntary contraction and 30 micro V electromyographic activity. Pain and fatigue was measured on visual analog scales before and after the biting, as well as before and after 10 min chewing. Statistical comparison showed that the masseter muscle was significantly thicker (+15%) in the short-faced than the normal- to long-faced subjects. The pain onset time and endurance time were also consistently shorter in short-faced subjects, whereas the intensity of pain and fatigue did not differ significantly between the two groups. Multiple stepwise regression showed positive influence from the mandibular plane inclination and the masseter thickness on the pain onset time and endurance time. The present findings support the concept that subjects with different craniofacial morphology show neuromuscular differences.

The aim of this study was to investigate the relationship between the curve of Spee and skeletal facial morphology. Dental casts and lateral cephalograms were obtained from 59 orthodontic patients. The amount of concavity of the curve of Spee was calculated by a second-order quadratic interpolation of buccal cusp tips obtained from lateral digital photographs of the teeth. The cephalometric analysis aimed to evaluate the sagittal and vertical craniofacial dimensions as well as the position of the mandibular condyle with respect to the occlusal plane. These variables, included in a multiple regression model, could explain 34% of the total variance of the curve of Spee. The amount of the curvature was significantly related to (a) the horizontal position of the condyle with respect to the dentition, (b) the sagittal position of the mandible with respect to the anterior cranial base, and (c) the ratio between the posterior and anterior facial height. No significant relationship was found between the curve of Spec and any of the other cephalometric variables. The curve of Spee was not influenced by age and gender of the subjects investigated.

BACKGROUND: The purpose of this retrospective study was to identify the subjective and objective characteristics of a population referred to a clinic for diagnosis and treatment of orofacial pain and/or temporomandibular disorders. METHODS: Beginning in 1993, 825 patients, consecutively referred to the University of Naples Federico II , were examined and their records entered into a database. These data were collected by trained clinicians. Diagnostic subgroups were identified following the Research Diagnostic Criteria for temporomandibular disorders (RDC). RESULTS: Seventy-nine percent of patients were female, the mean age of the sample was 31.3+/-13 years (range: 5 to 74 years), most of patients were between 15 and 39 years of age. Based on diagnostic subgroups, patients were divided into: patients affected with myogenous pain (59%), arthrogenous pain (13%), arthrogenous and myogenous pain (16%) and fibromyalgia (4%). Sixty-three percent of the sample reported recent headaches, 53% reported parafunction, and 28% reported a previous trauma. Eighty-one percent reported spontaneous pain, which was chronic in 83% of them. The majority of patients (78%) presented a relatively high cultural BACKGROUND. CONCLUSIONS: These data appear to agree with other epidemiologic studies and depict the TMD treatment-seeking population as a predominantly female population during child-bearing years with multiple chronic pain complaints.

The observation that the masticatory system and the postural body regulating system are anatomically and functionally related, has led to postulate several hypotheses of correlation between occlusal and postural disturbances. In the last decade, these arguments have gained a great social impact, also because they have been broadly spread by the mass-media. As a consequence, there has been a growing number of patients seeking concomitant occlusal and postural treatments. The aim of this study was to review critically the current evidence of correlation between the two systems; this in order to address clinical issues for the management of patients. Methodology of the studies reviewed has been evaluated according to the criteria suggested by Storey and Rugh 20 rif. Although there are some evidences of correlation between occlusion and posture, this appears limited to the cranio-cervical tract of the column and tends to disappear when descending in cranio-caudal direction. On the basis of this review of the literature, it's not advisable to treat postural imbalance by means of occlusal treatment or vice versa, particularly if the therapeutic modalities are irreversible.

To test the hypothesis that the ovarian cycle influences the pressure-pain threshold of the masticatory muscles.Eighteen healthy women with a regular menstrual cycle (28 +/- 2 days), ranging in age from 18 to 35 years, participated in the study. For each subject, pressure-pain thresholds (PPTs) of the masseter and temporalis muscles were assessed at 4 muscular sites by means of an electronic algometer. Measurements were taken at 4 separate sessions across the menstrual cycle corresponding to the following phases: menstrual, follicular, periovulatory, and luteal. Menstrual cycle phases were determined by a pelvic ultrasonographic screening. The study was carried out in a single-blind design, and the initial session was randomly determined for each individual. Data collected were analyzed by repeated-measures analysis of variance.The findings suggest that the PPTs of several masticatory muscles (2 of 4) are influenced by the ovarian cycle, but to a minor extent (P0.05), and the influence is of limited clinical relevance.In healthy subjects, there is a link between mechanical sensitivity of the masticatory muscles and fluctuation of the ovarian hormones. The relationship between PPTs of the masticatory muscles and the ovarian cycle should be also investigated in patients with temporomandibular disorders and/or orofacial pain conditions.

The aim of this study was to evaluate the short-term effects of orthodontic pain on the pressure pain threshold (PPT) of the masseter and anterior temporalis muscles, and on their electromyographic (EMG) activity during clenching and chewing. Orthodontic pain was induced in 14 healthy subjects (mean age 26.6, SEM 1.1) by placing orthodontic separators. The subjects were randomly assigned to an experimental and to a control session in a double-blind crossover study. PPT was significantly reduced (Student's t-test; P < 0.001) after experimental sessions for both the masseter and the anterior temporalis muscles, whereas no significant differences were found during control sessions (P > 0.05). EMG activity during clenching and chewing was significantly reduced (0.001 less than or equal to P < 0.05) after experimental sessions for both masseter and anterior temporalis muscles, whereas no significant differences were found during control sessions (P > 0.05). The decrease of PPT found in this study can be related to the occurrence of muscle pain and headache reported by patients during orthodontic or other dental treatment. The decrease of EMG activity of the jaw muscles associated with orthodontic pain is consistent with the pain adaptation model and should be considered as a potential factor for loss of occlusal anchorage during orthodontic treatment.

The twin method is one of the most effective methods available for investigating genetically determined variables in orthodontics, as well as in other medical fields, depending on the variance in the shape and the size of skull and teeth, both on genetic and environmental influences. The former have been extensively evaluated and, in particular, most of the facial and dental cephalometric parameters have shown high heritability, the vertical parameters have a higher genetic control compared with the horizontal ones. Nevertheless, most of the results provided by twin research have been considered arbitrary if directly transferred to a singleton population and in further studies, including extensive analysis of the parents, familial and nutritional habits have been recommended. In this study, heritability of 39 lateral orthodontic cephalometric parameters has been estimated by both statistical method of path analysis and Dahlberg' quotient in three orthodontic samples of young monozygotic and dizygotic twins and same-sex pairs of singletons living together, matched for sex and age, to evaluate genetic versus environmental factors affecting heritability of craniofacial features in the aim to obtain results not only statistically significant but also transferrable to a singleton population. Different inheritance trends, showing the highest concordance of values between monozygotic twin pairs when compared with dizygotic twin pairs or the same-sex singletons paired group, come from the 39 selected lateral cephalometric parameters, confirming the hypothesis that strong genetic control is exerted especially on the vertical ones. Heritability seems to have more influence on anterior vertical parameters than posterior. Mandibular structure seems to be more genetically determined than mandibular size. All five Ricketts' cephalometric typological parameters confirm high heritability coefficients, the same applies to the linear horizontal McNamara's measurement and lower incisor to A-Pg line. The two tested statistical methods showed relevant concordance of results. (Am J Orthod Dentofac Orthop 1997;111:44-51.)

SUMMARY The present study investigated the effects of a recycling technique on orthodontic ceramic brackets by means of a scanning electron microscope analysis. The weight and dimension changes of brackets recycled one, five and ten times compared with new ones were evaluated. The results suggest that changes in weight (+4.27 mg), in buccal and base slot widths (-0.0013 inches), in slot depth (+0.0014 inches) and in the total bracket base area (+ 1.46 mm 2 ) are of little clinical relevance. The shear bond strengths of recycled versus new ceramic brackets were then evaluated and compared. The mean values for new ceramic brackets and brackets recycled one, five and ten times were 15.52, 11.23, 10.10 and 10.04 MPa, respectively, indicating that recycled ceramic brackets provide shear bond strengths adequate for clinical use. Moreover, they exhibit bond failures mostly at the bracket/adhesive interface, without causing enamel damage.