Roberto Deli

Automated landmark extraction for orthodontic measurement of faces using the 3-camera photogrammetry methodology.

Objectives: To set up a three-dimensional photogrammetric scanning system for precise landmark measurements, without any physical contact, using a low-cost and noninvasive digital photogrammetric solution, for supporting several necessity in clinical orthodontics and/or surgery diagnosis. Materials and Methods: Thirty coded targets were directly applied onto the subjects face on the soft tissue landmarks, and then, 3 simultaneous photos were acquired using photogrammetry, at room light conditions. For comparison, a dummy head was digitized both with a photogrammetric technique and with the laser scanner Minolta Vivid 910i (Konica Minolta, Tokyo, Japan). Results: The precise measurement of the landmarks is ranged between 0.017 and 0.029 mm. The system automatically measures spatial position of face landmarks, from which distances and angles can be obtained. The facial measurements were compared with those done using laser scanning and manual caliper. The adopted method gives higher precision than the others (0.022-mm mean value on points and 0.038-mm mean value on linear distances on a dummy head), is simple, and can be used easily as a standard routine. Conclusions: The study demonstrated the validity of photogrammetry for accurate digitization of human face landmarks. This research points out the potential of this low-cost photogrammetry approach for medical digitization.

Relationship between chronic nasal obstruction and craniofacial growth : an experimental model

The aim of this paper was to verify if the growth of the nasomaxillary complex can be influenced by a purely functional alteration such as nasal obstruction, which was induced experimentally in a genetically controlled animal model. Sixty albino rats were employed. Twenty of them had the right nostril occluded by a synthetic resin; another twenty had both nostrils occluded; the other 20 were taken as control group. When the growth was completed, the rats were sacrificed and cephalometric analysis was carried out. Both treated groups showed a statistically significant reduction in overall weight and height, in the vertical development of the nasomaxillary complex and in the skullbase longitudinal axis. After discussing the literature on the subject, the authors conclude that normal craniofacial growth in the rat must somehow depend on physiological nasal breathing, which should therefore be considered of crucial importance.

Management of Craniofacial Development in the Parry-Romberg Syndrome: Report of Two Patients

Objective The aim of this article is to describe the orthodontic therapy for Parry-Romberg syndrome. The therapeutic goal is to minimize the wasting effects of progressive atrophy on facial development of a part of the face. Design To correct problems affecting craniofacial development of these patients, occurring during puberty, an orthodontic appliance was employed, which helps maintain parallelism of the facial planes, in particular the mandibular plane. Setting Orthodontic care was carried out in the Dental Clinic of the Catholic University of the Sacred Heart of Rome. Intervention Two patients underwent orthodontic therapy for 6 years. Appliances were checked every month and modified periodically so as to adapt to facial bone growth. Results At the end of craniofacial growth, the mandible was almost symmetric and the problem relating to atrophy remained confined to the initial area. Cephalometric analyses demonstrated that the occlusal plane and the mandibular plane maintained a straight orientation in relation to the bizygomatic plane. The ratio between the left and right side of the ramus and condyle, in the mandible, improved. Conclusions The use of orthodontic therapy allows patients affected by hemifacial progressive atrophy to present a more harmonic face at the end of puberty when final reconstruction can be planned. These results provide for a limitation of surgical intervention to the sclerodermic area alone.

Evaluation of 2 different reference planes used for the study of asymmetric facial malformations

The purpose of this study was to evaluate if Frankfort plane (FH) and plane passing through the lateral semicircular canals (LS) can be used as reference planes in three-dimensional analysis. Ten patients with facial asymmetry underwent a three-dimensional computed tomography. Computed tomographic images were processed by means of a commercial software and a personal computer to obtain a three-dimensional virtual craniofacial model. The average Frankfort plane and the plane passing through the LS were identified. The distance from the above-mentioned planes to the first upper molar and upper canine cusp was measured. It was not possible to detect an FH plane in any of the patients. Right FH, left FH, average FH, and LS plane were traced. The discrepancies among reference planes were significant in cases with severe asymmetry. A minimal discrepancy was noticed in patients with light asymmetry. In patients with severe asymmetry, the LS plane results in steady, reproducible, detectable, and closer to the patients anatomy, representing a valid reference plane for three-dimensional computed tomography analysis.

Accurate facial morphologic measurements using a 3-camera photogrammetric method.

Objectives:A new, low-cost photogrammetric method has been developed for facial morphometry applications. To evaluate the system, tests for the measurement and comparison of three-dimensional virtual faces were carried out in different subjects. Materials and Methods:Twenty adult white Italian subjects, 10 men and 10 women, of ages ranging from 23 to 37 years, were included in this study. Three cameras were finely calibrated, and the point precision vector length was calculated, together with the quality parameters. For each subject, 3 different acquisitions were performed. A tessellated surface was obtained from each point cloud. The comparison was made by aligning three-dimensional information from different models. Differences between 2 different models were estimated by analysis of the distances. Results:For the cases analyzed, the mean point precision overall root-mean-square vector length was 0.07 mm, with a SD of 0.027 mm. The results are reported for the systems capability of discriminating between the faces of different people. Results of comparisons between facial models of a single person were compared with those of comparisons between different subjects. Students t-test revealed that the system was able to discriminate among different people, with a P > 95%. Two sex subgroups were formed: the mean error between subgroups ranged from 1.65 to 3.43 mm, and the mean ranged from 1.76 to 2.72 mm. Conclusions:The experiments confirmed the capabilities and the accuracy of the proposed photogrammetric system. Facial comparison was performed by analysis of distances on three-dimensional virtual models.

Orthodontic treatment attitude versus orthodontic treatment need: differences by gender, age, socioeconomical status and geographical context

OBJECTIVES To investigate the relationship between the attitude towards orthodontic treatment and the objective level of orthodontic need, and variables like gender, socioeconomic status and geographical context, among 6- to 16-year-old children. METHODS The attitude of 2284 Italian children towards orthodontics was assessed using the Child Orthodontic Attitude Survey (COAS) questionnaire, previously validated for Italian-speaking children. The level of orthodontic need was evaluated by using the Risk of Malocclusion Assessment (ROMA) Index while socioeconomic status (SES) was based on parental job activities. The univariate analysis was performed using chi-square tests to find differences between groups for categorical variables, while multivariate analyses were conducted using logistic regression models. RESULTS Individuals with a higher SES had a statistically significant lower need of orthodontic treatment (P = 0.003). Children with a very high SES were from northern (20.8%) and central Italy (65.9%), while only 13.3% lived in southern Italy (P < 0.001). Logistic regression showed that females, older children, in-treatment subjects and children from the region of Puglia were more likely to have orthodontics (OR = 2.09; 95% CI: 1.66-2.64, OR = 1.08; 95% CI: 1.01-1.15, OR = 1.48, 95% CI: 1.11-1.97, OR = 1.43; 95% CI: 1.05-1.95, respectively). CONCLUSIONS The orthodontic treatment attitude largely depends on age, gender and geographical context but is not influenced by the real level of orthodontic therapy need.

Relationship between vertical facial patterns and dental arch form in class II malocclusion

BackgroundThe purpose of this study is to evaluate the relationship between dental arch form and the vertical facial pattern determined by the angle between the mandibular plane and the anterior cranial base (Sella-nasion/mandibular plane angle (SN-MP)) in skeletal class II untreated patients.MethodsA sample of 73 Caucasians patients with untreated skeletal class II in permanent dentition was divided into three groups according to the values of the angle SN-MP. An evaluation of the arch form was performed by angular and linear relation values on each patient. Regression analysis was used to determine the statistical significance of the relationships between SN-MP angle and dental arch form. The differences among the three groups were analyzed for significance using a variance analysis.ResultsA decrease of the upper arch transversal diameters in high SN-MP angle patients and an increase in low angle SN-MP ones (P < 0.05) were shown. Result analysis showed a change in upper arch shape, with a smaller intercanine width in patients with high SN-MP angle and a greater one in low angle patients. As SN-MP angle increased, the upper arch form tended to be narrower. No statistically significant difference in mandibular arch form among the three groups was found, except the angle value related to incisors position.ConclusionsThe results showed the association between the upper dental arch form and the vertical facial pattern. On the contrary, the lower arch form was not related to the mandibular divergence.

Three-dimensional methodology for photogrammetric acquisition of the soft tissues of the face: a new clinical-instrumental protocol

BackgroundThe objective of this study is to define an acquisition protocol that is clear, precise, repeatable, simple, fast and that is useful for analysis of the anthropometric characteristics of the soft tissue of the face.MethodsThe analysis was carried out according to a new clinical-instrumental protocol that comprises four distinct phases: (1) setup of portable equipment in the space in which field analysis will be performed, (2) preparation of the subject and spatial positioning, (3) scanning of the subject with different facial expressions, and (4) treatment and processing of data. The protocol was tested on a sample comprising 66 female subjects (64 Caucasian, 1 Ethiopian, and 1 Brazilian) who were the finalists of an Italian national beauty contest in 2010. To illustrate the potential of the method, we report here the measurements and full analysis that were carried out on the facial model of one of the subjects who was scanned.ResultsThis new protocol for the acquisition of faces is shown to be fast (phase 1, about 1 h; phase 2, about 1.5 min; phase 3, about 1.5 min; phase 4, about 15 min), simple (phases 1 to 3 requiring a short operator training period; only phase 4 requires expert operators), repeatable (with direct palpation of anatomical landmarks and marking of their positions on the face, the problem of identification of these same landmarks on the digital model is solved), reliable and precise (average precision of measurements, 0.5 to 0.6 mm over the entire surface of the face).ConclusionsThis standardization allows the mapping of the subjects to be carried out following the same conditions in a reliable and fast process for all of the subjects scanned.

Comparison between different interdental stripping methods and evaluation of abrasive strips: SEM analysis

OBJECTIVES The aim of this study was to evaluate the morphological effects and the surface irregularities produced by different methods of mechanical stripping (abrasive strips and burs) and chemical stripping (37% orthophosphoric acid) and the surface changes following the finishing procedures (polishing strips) or the subsequent application of sealants, in order to establish the right stripping method that can guarantee the smoothest surface. We have also analysed the level of wear on the different abrasive strips employed, according to their structure. MATERIALS AND METHODS 160 proximal surfaces of 80 sound molar teeth extracted for orthodontic and periodontal reasons, were divided into: 1 control group with non-treated enamel proximal surfaces and 5 different groups according to the stripping method used, were observed with scanning electron microscopy (SEM). Each one of the 5 treated groups was also divided into 3 different subgroups according to the finishing procedures or the subsequent application of sealants. RESULTS The finishing stage following the manual reduction proves to be fundamental in reducing the number and depth of grooves created by the stripping. After the air rotor stripping method, the use of sealants is advised in order to obtain a smoother surface. The analysis of the combinations of mechanical and chemical stripping showed unsatisfactory results. Concerning the wear of the strips, we have highlighted a different abrasion degree for the different types of strips analysed with SEM. CONCLUSIONS The enamel damages are limited only if the finishing procedure is applied, independently of the type of abrasive strip employed. It would be advisable, though clinically seldom possible, the use of sealants after the air rotor stripping technique.

Association between oral habits, mouth breathing and malocclusion

SUMMARY The ratio of bad habits, mouth breathing and malocclusion is an important issue in view of prevention and early treatment of disorders of the craniofacial growth. While bad habits can interfere with the position of the teeth and normal pattern of skeletal growth, on the other hand obstruction of the upper airway, resulting in mouth breathing, changes the pattern of craniofacial growth causing malocclusion. Our crosssectional study, carried out on 3017 children using the ROMA index, was developed to verify if there was a significant correlation between bad habits/mouth breathing and malocclusion. The results showed that an increase in the degree of the index increases the prevalence of bad habits and mouth breathing, meaning that these factors are associated with more severe malocclusions. Moreover, we found a significant association of bad habits with increased overjet and openbite, while no association was found with crossbite. Additionally, we found that mouth breathing is closely related to increased overjet, reduced overjet, anterior or posterior crossbite, openbite and displacement of contact points. Therefore, it is necessary to intervene early on these aetiological factors of malocclusion to prevent its development or worsening and, if already developed, correct it by early orthodontic treatment to promote eugnatic skeletal growth.