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Background. Orthodontic devices modify patient's occlusion but there is no consensus on the number, the distribution and the intensity of dental contact points characterising post-orthodontic treatment occlusion. This paper deals with the description of the morphological and functional problems related to it. The aim of this study is to propose a method correlating distribution, area and intensity of contact points with the activation of mandibular elevating muscles measured with standardized surface electromyography. Materials and methods. Five subjects without signs and symptoms of temporomandibular disorders which underwent orthodontic treatment were included in the study. Silicone impressions were taken for occlusal registration before and after treatment. Maximal voluntary clenching registrations were made with and without cotton rolls interposed between the dental arches, in order to standardise all potential as a percentage of clenching tests. Electromyographic indices (Percental Overlapping Coefficient (POC), asymmetry, activation, torque, impact) were recorded using a 4-channel electromyograph (EasyMyo®) before and after orthodontic treatment. Contact areas in the occlusal recordings were analysed with the method of trans-illumination to evaluate number, area and distribution of contacts. Results. In all cases, muscle activation indexes are normal. There is a slight decrease in POC of the temporalis (p ≤ 0.05). The activation index is positive in all the cases examined and increased after therapy (p ≤ 0.05). The Pearson correlation index between dental contacts symmetry and muscular activation symmetry was calculated and showed statistical relevance for the POC of the masseter (at 100 μm, p ≤ 0.05; 50 μm p ≤ 0.01) and for the mean POC (at 50 μm and 0 μm, p ≤ 0.05). Conclusions. The variation of the electromyographic indices is supposed to be a consequence of neuromuscular adaptations to the new occlusal morphology after orthodontic treatment, when both morphological and functional symmetry are needed. The variations of the electromyographic indices are in line with what is expected from the biological and functional point of view of the muscular activity. The illustrated method is valid and can be applied for further evaluation. [ABSTRACT FROM AUTHOR]

Introduction: The study of occlusion is fundamental in clinical practice. The methods commonly used for the analysis of the occlusion often provide only qualitative information, not very reliable, making these methods poorly reproducible. Purpose of the study: The aim of the study is the validation of a method for occlusal analysis in order to overcome the limits of existing techniques and guarantee an accurate analysis of the occlusion of patients. This method is based on the transillumination indices. Materials and methods: The method allows evaluating the extension of contact areas and contact points using ImageJ software, developed by NIH. Chips of the impression material at a different thickness (150, 100, 50 µm) have been considered. These chips are scanned. Dental occlusal registrations of 20 healthy patients were scanned and contacts points and areas have been measured at different thickness (150, 100, 50, <50, 0 µm). Results: The repeatability test demonstrated the validity of the method (technical error lower than 15%, except the measurements at 0 µm). Conclusions: It is possible to assert that this method is a promising and valid alternative to common techniques. Thanks to its reproducibility and objectivity it is possible to evaluate the quantitative data it provides about occlusal areas and contacts. [ABSTRACT FROM AUTHOR]

Background One of the treatment option to reduce spasticity in cerebral palsy children is selective dorsal rhizotomy. Several studies have demonstrated short and long term improvements in gait and other activities after rhizotomy but this surgery still remains a controversial procedure and patient outcome indicators measures are not uniform. Aims To describe our assessment and outcome evaluation protocol and to verify by this protocol short term results of rhizotomy. Methods We recruited 9 cerebral palsy children (mean age 7.9 years ± 3.2) affected by mild to moderate spastic diplegia and operated by rhizotomy. Patients were studied preoperatively and at 12 months after surgery by the following clinical and instrumental measures correlated to the International Classification of Functioning: modified Ashworth Scale, passive Range of Motion, Medical Research Council Scale, Selective Motor Control Scale, 3D-motion analysis and energy cost of locomotion measurements (indicators of “body functions”); Gross Motor Functional Measure and Motor Functional Independence Measure (indicators of “activities and participation”). Results Our data showed, after rhizotomy, reduction of spasticity specially in plantarflexors muscles ( p < 0.01), increase of strength of knee flexors/extensors and foot plantar/dorsiflexion muscles ( p < 0.01), improvement of selective motor control ( p < 0.05), more similar spatio-temporal parameters of gait analysis to healthy subjects, reduced equinus foot and knees hyperflexion as energy cost. Conclusion The complementary use of multiple indicators may improve the evaluation of the results of dorsal rhizotomy. A beneficial outcome measured by these indicators has been found in our spastic diplegic children one year after rhizotomy. [ABSTRACT FROM AUTHOR]

Objective: The aim of this investigation was to compare the pattern of temporomandibular disorder (TMD) diagnoses in clenching patients with different occlusal features, the null hypothesis being that no between-group differences exist. Materials and Methods: Two groups of subjects receiving a jaw clenching diagnosis and having large overjet or anterior open bite (Group A; N=45, 75.5% females, mean age: 38.1 +/- 15.9 years) or normal occlusion (Group B; N=69, 71% females, mean age: 34.6 +/- 13.8 years) were recruited among a TMD patient population and were given Research Diagnostic Criteria for TMD (RDC/TMD) axis I diagnoses, namely, group I muscle disorders, group II disc displacements, and group III arthralgia/osteoarthritis/osteoarthrosis. Major Findings: The distribution of RDC/TMD single and combined group diagnoses was significantly different between the two groups (P<0.05), with Group A subjects showing a higher prevalence of multiple diagnoses (60% versus 43.3%), as well as a higher prevalence of combined RDC/TMD axis I group II and III diagnoses (37.8% versus 20.2%). All TMD signs and symptoms were more frequent in the patients with large overjet or anterior open bite with respect to the patients with normal occlusion. Conclusion: In a TMD patient population, jaw clenching may have different consequences in subjects with large overjet or anterior open bite with respect to subjects featuring normal occlusion. [ABSTRACT FROM AUTHOR]

Objective: The main purpose of this preliminary study was to propose an original analysis of facial soft tissues'' depth to detect their topographic variability, which causes are intrinsic (depth) and extrinsic (bone shape and reciprocal correlations with soft tissues themselves). To check the utility and accuracy of the method in recognizing measures'' differences, other aims were comparison of two different groups of people and statistical validation. Study design: The study sample was composed of 100 consecutive patients (56 females and 44 males) undergoing a routine CT scanning. The images, obtained through the reference plane of the palate, were post-processed on a PC workstation. A goniometer construction was superimposed and centered on the posterior nasal spine, where a grid of eighteen rays was developed to calculate the superficial soft tissues'' depths of the face. To test the validity of the method, three of the rays were measured twice, by the same as by another observer. Step-by-step procedures were attained to get maximum standard in measures'' reliability. Results: Superficial soft tissues'' depths were obtained and sex differences were analyzed (Student''s t and Wilcoxon rank-sum test). The statistical reliability was proven with Bland-Altman statistics and the upper 95% limit of agreement was 1.459 mm for intraobserver repeatability and 1.886 mm for interobserver reproducibility. Validation of the method was proven by intraclass correlation coefficient (0.99 both for repeatability and reproducibility) and mean differences (respectively 0.6% and 0.4%). Conclusion: The method appeared easy to be applied, reliable and not observer dependent, so suitable for study single as multiple patients with CT images. Future analyses shall be possible. [Copyright &y& Elsevier]

Several works showed a decreased role for occlusion in the etiology of temporomandibular disorders (TMD). Nonetheless, it may be hypothesized that occlusion acts as a modulator through which bruxism activities may cause damage to the stomatognathic structures. To test this hypothesis, a logistic regression model was created with the inclusion of clinically diagnosed bruxism and eight occlusal features as potential predictors for temporomandibular joint (TMJ) pain in a sample of 276 consecutive TMD patients. The final Iogit showed that the percentage of the total log likelihood for TMJ pain explained by the significant factors was small and amounted to 13.2%, with unacceptable levels of sensitivity (16.4%). The parameters overbite ≥ 4 mm combined with clinically diagnosed bruxism [OR (odds ratio) 4.62], overjet ≥ 5 mm (OR 2.83), and asymmetrical molar relationship combined with clinically diagnosed bruxism (OR 2.77) were those with the highest odds for disease, even though none of those values was significant with respect to confidence intervals. Thus, the hypothesis under evaluation has to be rejected. It is possible that future studies with a higher discriminatory power for the different bruxism activities might be indicated to get deeper into the analysis of the potential mechanisms through which occlusion may play a role, even if small, in the etiology of the different TMD. [ABSTRACT FROM AUTHOR]

Purpose: To develop a noninvasive 3-dimensional method to evaluate labial morphology and to assess gender-related differences in healthy young adults. Materials and Methods: Dental and lip impressions of 11 men and 10 women aged 21 to 34 years, with sound, full, permanent dentition were obtained. The models were digitized and 3-dimensional virtual reproductions obtained. The labial thickness, vermilion area, and volume of the upper and lower lips were measured from the digital reconstructions. The male and female data were compared using Student''s t test. Results: The mean lip thickness was significantly larger (P = .02) in men (14.3 mm) than in women (12.3 mm). The lower lip was thicker than the upper lip. The vermilion width was larger in men (75 mm) than in women (70 mm), and no differences were found for vermilion height (10 mm). In the upper lip, the height/width ratio was significantly larger in women (14.1%) than in men (12.3%). The vermilion surface area was slightly larger in men than in women (upper lip area: women, 467 mm2; men, 501 mm2; lower lip area: women, 491 mm2; men, 569 mm2). The labial volume was significantly larger in men (upper lip, 2,390 mm3; lower lip, 2,902 mm3) than in women (upper lip, 1,743 mm3; lower lip, 1,764 mm3; P = .021). The upper/lower lip area and volume ratios were similar in the 2 genders. Conclusions: Overall, men had larger lips than women. The inferior lip height/width ratio was similar in both genders, and men had a relatively thinner upper lip than women. [Copyright &y& Elsevier]

This is a case of unilateral masseter muscle hypertrophy (MMH) treated with botulinum toxin (NHAI-normalised hemi-facial asymmetry index improvement from 5.48 to 3.04). After 19 months the treatment was repeated because of hypertrophy relapse (NHAI increase up to 6.82). The volume variations in the masseter area were monitored during 25 months using a laser scanner to compute facial volume. In order to relate the cause of hypertrophy and relapse to the presence of parafunctional activities, a nocturnal electromyography (EMG) study was conducted with positive results (nocturnal parafunctions of patients 4074.99 microV to be compared with a control group value of 1644.63 microV). The lack of the left inferior molars and the consequent right occlusal support seemed to justify the hypertrophy of right masseter (MMRight-POC [percent overlapping coefficient] 91.9%). However, the prosthetic rehabilitation did not prevent relapse in the same muscle. The EMG analysis of both the muscular activation (MMRight-POC 66.0% after relapse) and inhibition activity in Maximum Voluntary Clench (MVC) resulted in contradictory conclusions. At present, the available knowledge regarding MMH physiopathology is very limited and does not support a therapeutic rationale for relapse prevention. [ABSTRACT FROM AUTHOR]

This is a case of unilateral masseter muscle hypertrophy (MMH) treated with botulinum toxin (NHAI - normalised hemi-facial asymmetry index improvement from 5.48 to 3.04). After 19 months, the treatment was repeated because of hypertrophy relapse (NHAI increase up to 6.82). The volume variations in the masseter area were monitored during 25 months using a laser scanner to compute facial volume. In order to relate the cause of hypertrophy and relapse to the presence of parafunctional activities, a nocturnal electromyography (EMG) study was conducted with positive results (nocturnal parafunctions of patients 4074.99 µV to be compared with a control group value of 1644.63 µV). The lack of the left inferior molars and the consequent right coclusal support seemed to justify the hypertrophy of right masseter (MMRight-POC [percent overlapping coefficient} 91.9%). However, the prosthetic rehabilitation did not prevent relapse in the same muscle. The EMG analysis of both the muscular activation (MMRight-POC 66.0% after relapse) and inhibition activity in Maximum Voluntary Clench (MVC) resulted in contradictory conclusions. At present, the available knowledge regarding MMH physiopathology is very limited and does not support a therapeutic rationale for relapse prevention. [ABSTRACT FROM AUTHOR]

Purpose: To noninvasively assess the facial soft tissues and masticatory muscle function before and after orthognathic surgery. Patients and Methods: Eight patients aged 18 to 36 years, all with a skeletal Class III and mandibular asymmetry, were assessed both before (on average, 2 months) and after (on average, 10.5 months) surgical intervention (mandibular reduction by sagittal split osteotomy and Le Fort I maxillary advancement). From the 3-dimensional coordinates of soft tissue facial landmarks, the inclination of facial planes was calculated. Surface electromyography of the masticatory muscles was performed and indices of muscular activity computed. Data were compared with reference values collected in healthy subjects of the same gender, age, and ethnic group. Results: Before surgery, facial planes were significantly less horizontal (frontal plane) than in the reference subjects (P < .05). The sagittal projection of the mandibular plane was more inclined relative to the norm (P < .001). During teeth clenching, all indices of standardized muscular symmetry, torque, and activity (P < .05) were smaller than the reference values. After surgical treatment, the inclinations of facial planes became more homogenous (P < .05). The inclination of the frontal and sagittal planes came next to the reference values, but still differed significantly in the patients (P < .05). The mean symmetry index of masseter muscle, torque coefficient, and pooled muscle activity increased, but the patient values remained significantly under the reference values (P < .05). Conclusion: The morphologic and functional approach used in this study proved useful as a complementary diagnostic aid, enabling quantitative evaluation of the final results of surgery, without submitting the patients to invasive procedures. [Copyright &y& Elsevier]

Objective: To evaluate morphologic characteristics of occlusion (contact points, contact areas, and frequency of contact) in clinically successful patients 1 year after orthodontic and surgical-orthodontic therapy followed by passive retention. Materials and Methods: Twenty-two orthodontic and 18 surgical-orthodontic patients were analyzed. All patients were treated with standard edgewise technique by the same orthodontist. Contact points and areas were evaluated using a new method of digital image analysis of occlusal impressions. Polivinylsyloxan impressions were taken, scanned, and turned into gray-scale images. The physic relationship of light absorbance through the polivinylsyloxan for known thickness was calculated to determine contact areas (less than 50 µm of thickness) and near contact areas (less than 350 µm of thickness). Results: The contact area was significantly larger in the orthodontic than in the surgical-orthodontic patients (Student's t-test, P < .05). The surgical-orthodontic group had significantly fewer contact points than the orthodontic group only at 150 µm of thickness. In both groups of patients, the first molar had the largest contact surface. Occlusal support was distributed mainly in the posterior regions with an important role involving the first molars. Conclusion: Surgical-orthodontic patients appear to have smaller contact surfaces and fewer contact points than orthodontic patients do. However, there were no differences in the number of teeth in contact with opposing teeth. [ABSTRACT FROM AUTHOR]

Abstract: Nine patients aged between 18 and 35 years who had severe skeletal Class III malocclusion and moderate-to-severe mandibular asymmetry, were assessed by a non-invasive, landmark-based, three-dimensional system before and after mandibular reduction by sagittal split osteotomy and LeFort I maxillary advancement. The three-dimensional coordinates of 50 facial soft tissue landmarks were collected, and a series of anthropometric measurements was calculated and compared with reference values from 240 healthy subjects of similar sex, age, and ethnic group. Patients were more asymmetrical than normal subjects before the operations, particularly in the gonion. Postoperatively, total and lateral asymmetry was considerably reduced. The three-dimensional approach was a valuable complementary diagnostic aid that enabled quantitative evaluation of the final soft-tissue results without invasive procedures. [Copyright &y& Elsevier]

Summary: Background: To obtain the best surgical results in orthognathic surgery, treatment planning and the evaluation of results should be performed on measurable three-dimensional reproductions of the face of the patients, and compared to reference subjects. Methods: Seven women aged 18–35 years, all with a skeletal Class III and mandibular asymmetry, were assessed both before (on average, 2 months) and after (on average, 10.7 months) surgical intervention (mandibular reduction by sagittal split osteotomy and LeFort I maxillary advancement). The three-dimensional coordinates of 50 soft tissue facial landmarks (face, eyes, nose, mouth and lips, ears) were collected with a noninvasive, electromagnetic digitizer; facial volumes were estimated, and compared to reference values collected in 87 healthy women of the same age and ethnic group. Inter-individual modifications in facial shape were also assessed. Results: Before surgery the patients had smaller faces than the reference women, with larger lower lips and noses. A large within-group variability was found. Surgical treatment significantly reduced total facial volume and mandibular volume, increased total and upper lip volumes (Student''s t test, p <0.05), and made all values more homogenous within the group. Shape differences were significantly larger before than after surgery. On average, right side gonion was the landmark that moved the most, closely followed by menton, while the tragi and ala nasi moved the least. The three-dimensional approach used in this study enabled quantitative evaluation of the final soft tissue results of surgery, without submitting the patients to invasive procedures. [Copyright &y& Elsevier]

Abstract

The aim of this study was to test the clinical efficacy of a new loop named 'cherry loop' in correcting the Class II relationship by the mesial movement of the first lower molars in the Tweed-Merrifield technique. We compared the amount of molar mesial movement in two groups of patients treated with upper first bicuspid and lower second bicuspid extractions. The study was conducted using two X-rays, one before treatment and one after the molars had move. Mandibular molars and incisors were traced and their positions analyzed along a Cartesian coordinate system. Movements were related to stable structures; lower borders of the mandible and the symphysis. The cherry loop performance was compared to that of the shoehorn loop. Cherry loop averaged 5.25 mm of average mesial movement, whereas the shoehorn loop yielded only 3.28 mm. The vertical control of molars was better too; we had 1.54 mm of distal movement of the crowns compared to 2.24 mm with the shoehorn loop. A serendipitous finding was that the occlusal plane could be controlled by the cherry loop. It can be oriented to best fit the growth pattern. In turn, in the growing patient, a favorable skeletal response can be expected. [ABSTRACT FROM AUTHOR]

The article presents a case report of an adolescent female presented with Class II skeletal and dental relationships and an anterior deep bite. The patient underwent overcorrection of the vertical position and torquing of the anterior incisors by means of the modified posted archwire. The article discusses torque and intrusion control of the upper inscisors with the help of archwire.