A retrospective comparison of functional appliance treatment of Class III malocclusions in the deciduous and mixed dentitions.

This retrospective study compared the effectiveness of treatment of Class III malocclusions with the removable mandibular retractor in the deciduous and mixed dentitions. A group of 20 children with Class III malocclusions started treatment at a mean age of 5 years 1 month +/- 7 months (deciduous dentition), while a group of 18 children with Class III malocclusions started treatment at a mean age of 8 years 2 months +/- 9 months (mixed dentition). The mean observation period was 2 years 3 months +/- 6 months for the first group, and 2 years 4 months +/- 7 months for the second group. Matched control groups of children with untreated Class III malocclusions in the deciduous and in the mixed dentition (16 subjects and 15 subjects, respectively) were used. The cephalometric analysis was based on a stable basicranial reference system appropriate for longitudinal studies that begin at early developmental ages. The results showed that treatment of Class III malocclusions in the deciduous dentition produced a more significant anterior morphogenetic rotation of the mandible, due to a more upward and forward direction of condylar growth (P < 0.01). This leads to significantly smaller increments in mandibular total length (Co-Pg) in children with Class III malocclusions under-going very early treatment (P < 0.01). On the contrary, maxillary dento-alveolar protrusion induced by therapy was greater in Class III subjects treated in the mixed dentition (P < 0.01). The optimum timing to improve skeletal relationships in Class III malocclusions by means of a functional appliance appears to be in the deciduous dentition.

[The correlations between the echographic aspect of the perioral and masticatory muscles and dento-skeletal characteristics]. / Correlazioni tra l'aspetto ecografico dei muscoli periorali e masticatori e le caratteristiche dento-scheletriche.

INTRODUCTION: US of some muscular components of the stomatognathic system (orbicularis oris and masseter muscles) has proved to provide important information about their morphologic features. The purpose of this study is to explore the US features of the perioral and masticatory muscles in patients affected with any type of malocclusion and to analyze the correlations between dento-skeletal characteristics and muscle changes. MATERIAL AND METHODS: We examined 26 untreated patients (10 men and 16 women); we measured their cephalometric parameters on lateral skull teleradiographs and then we measured with US both the masseter and orbicular muscles dimensions. The US images were acquired with 5 MHz and 7.5 MHz probes, measuring the masseter muscle with transversal and longitudinal scans, and the two parts of the orbicularis oris with longitudinal scans. The cephalometric measures were calculated with: angular parameters useful to determine the sagittal relationships, both angular and linear parameters to define the vertical relationships and angular measures that define the incisor position. We applied the Spearman test to assess if there was a relationship between the US dimensions of the orbicularis oris and the masseter, and the dento-skeletal characteristics of these 26 patients. RESULTS: Our results show that there is a strong correlation between mandibular morphology, the palatal plane, respectively, and the masseter length. There is a direct correlation with the masseter dimension for the palatal plane obliquity, and an inverse correlation for the mandibular morphology. The incisor position is influenced by the orbicular oris muscle dimension and by the asymmetric position of the superior and inferior incisors. CONCLUSIONS: This noninvasive diagnostic examination is a useful aid to the clinical examination of the muscles, especially in orthodontic diagnosis, together with MRI and CT, respectively more expensive and unhealthier.

Craniofacial changes following early prosthetic treatment in a case of hypohidrotic ectodermal dysplasia with complete anodontia.

The authors describe early prosthetic treatment in a case of hypohidrotic ectodermal dysplasia with complete anodontia. Craniofacial changes were analyzed by means of Ricketts' cephalometric analysis and superimposition methods. Early prosthetic treatment for complete anodontia determined a backward-downward rotation of the mandible with consequent normal positioning of the chin in the space, normalization in lower facial height, reduction in convexity of the face, and improvement in facial esthetics. Superimposition methods demonstrated that the direction of growth of both the maxilla and the mandible was progressing favorably. Improvements in esthetics and in the function of masticatory and perioral muscles, together with their positive psychological impact, were also discussed.

Skeletal effects of early treatment of Class III malocclusion with maxillary expansion and face-mask therapy.

The effectiveness of maxillary expansion and face-mask therapy in children with Class III malocclusion was studied in a sample of 46 subjects in mixed dentition and compared with a control sample of 32 subjects with untreated Class III malocclusion. Treated and untreated samples were divided into early and late mixed-dentition groups to aid identification of the optimum timing of the orthopedic treatment of the underlying skeletal disharmony. Cephalometric analysis was based on a stable basicranial reference system, appropriate for longitudinal studies started in the early developmental ages. The level of significance for intergroup comparisons was set at a p value of 0.01. Significant forward displacement of the maxillary complex was found in the early-treatment group. The region of the pterygomaxillary suture, in particular, showed significant changes in the subjects treated during early mixed dentition. No significant maxillary modifications were recorded in the late-treatment group. Both early and late groups exhibited smaller increments in mandibular protrusion and larger increments in the intermaxillary vertical relationship compared with their respective Class III control groups. Only children treated at an early age, however, showed a significant upward and forward direction of condylar growth, leading to smaller increments in total mandibular length. These results indicate that the combination of a bonded maxillary expander and face-mask therapy is more effective in early mixed dentition than in late mixed dentition, especially with regard to the magnitude of the protraction effects on maxillary structures.

Predictive variables for the outcome of early functional treatment of Class III malocclusion.

The aim of this study was to select a model of cephalometric and occlusal predictive variables for the results of early treatment of Class III malocclusion, due to mandibular protrusion in the deciduous dentition. Lateral cephalograms and dental casts of 45 subjects (22 boys and 23 girls) with Class III malocclusion in the deciduous dentition were analyzed at the start of treatment (mean age 5.57 +/- 0.85 years). The patients were treated with a functional appliance (removable mandibular retractor). All subjects were reevaluated after a mean period of 9.54 +/- 2.28 years comprising active treatment plus retention. At this time, the sample was divided into two groups according to occlusal criteria: successful group (23 subjects) and unsuccessful group (22 subjects). Stepwise variable selection on the measurements at the time of first observation identified three predictive variables; the inclination of the condylar axis in relation to the stable basicranial line (CondAx-SBL), the inclination of the nasal line to the mandibular line (NL-ML), and the transverse width of the mandibular arch measured at the first deciduous molars. Discriminant analysis assigned a classificative power of 95.55% to the predictive model. On the basis of the equation generated by the multivariate statistical method, outcome of early treatment for each new case with Class III malocclusion in the deciduous dentition can be accordingly predicted. The important role of both vertical and transverse relationships in Class III prognosis was emphasized.

Early dentofacial features of Class II malocclusion: a longitudinal study from the deciduous through the mixed dentition.

A group of 25 untreated subjects with Class II malocclusion in the deciduous dentition (featuring the concomitant presence of distal step, Class II deciduous canine relationship, and excessive overjet) was compared with a control group of 22 untreated subjects with ideal occlusion (flush terminal plane, Class I deciduous canine relationship, minimal overbite, and overjet) at the same dentitional stage. The subjects were monitored during a 2 1/2-year period in the transition from the deciduous to the mixed dentition, during which time no orthodontic treatment was provided. Occlusal analysis of the Class II group in the deciduous dentition revealed an average interarch transverse discrepancy due to a narrow maxillary arch relative to the mandible. All occlusal Class II features were maintained or became exaggerated during the transition to the mixed dentition. The skeletal pattern of Class II malocclusion in the deciduous dentition typically was characterized by significant mandibular skeletal retrusion and mandibular size deficiency. During the period examined, cephalometric changes consisted of significantly greater maxillary growth increments and smaller increments in mandibular dimensions in the Class II sample. Moreover, a greater downward and backward inclination of the condylar axis relative to the mandibular line, with consequent smaller decrements in the gonial angle, were found in the Class II group, an indication of posterior morphogenetic rotation of the mandible in patients with Class II malocclusion occurring during the period examined. The results of this study indicate that the clinical signs of Class II malocclusion are evident in the deciduous dentition and persist into the mixed dentition. Whereas treatment to correct the Class II problem can be initiated in all three planes of space (e.g., RME, extraoral traction, functional jaw orthopedics), other factors such as patient cooperation and management must also be taken into consideration before early treatment is started.

Glenoid fossa position in different facial types: a cephalometric study.

The purpose of the present study was to analyse the position of the glenoid fossa in subjects with different sagittal and vertical skeletal features. A cephalometric study was carried out on a sample of 180 subjects (90 males and 90 females, aged 7-12 years) who were combined to form three groups (60 subjects each) according to skeletal sagittal relationships and three groups (60 subjects each) according to skeletal vertical relationships. Cephalometric analysis comprised both sagittal and vertical measurements for the assessment of the position of the glenoid fossa in relation to surrounding skeletal structures. As for sagittal measurements, TMJ position was more posterior in skeletal Class II when compared with skeletal Class III. In the vertical plane, the position of the glenoid fossa relative to basicranial structures was more caudal in low angle subjects when compared with subjects with normal or high angle vertical relationships. Both basicranial structures and the posterior nasal spine may be used as reference structures for the assessment of vertical position of the glenoid fossa in diagnosis and treatment planning.

Role of posterior transverse interarch discrepancy in Class II, Division 1 malocclusion during the mixed dentition phase.

Posterior transverse interarch discrepancy (PTID), measured as the difference between the maxillary and mandibular intermolar widths, was investigated in a sample of 60 Class II, Division 1 subjects during the mixed dentition phase. Two main groups were detected: Class II group 1 (30 subjects) with PTID and Class II group 2 (30 subjects) without PTID. A sample of 30 Class I subjects in the mixed dentition phase was used as a control group. In Class II group 1, PTID was found to be due to a significantly narrower maxillary arch. The craniofacial skeletal features of both Class II groups and of the Class I group were assessed. The Class II group with PTID showed mandibular retrusion associated with a posteriorly displaced mandible of normal size (functional mandibular retrusion). The Class II group without PTID had mandibular retrusion due to a micrognathic mandible (anatomic mandibular retrusion). The relevance of these findings for treatment planning in Class II, Division 1 malocclusion in the mixed dentition was stressed.

Floating norms for the assessment of craniofacial pattern in the deciduous dentition.

This study provides norms for the evaluation of individual skeletal patterns in subjects with full deciduous dentition. The method is based on the associations among correlated craniofacial measurements (S-N-A, S-N-B, NL-NSL, ML-NSL, N-S-Ba). The results are given in a graphical box-like form (floating norms). An easy practical procedure allows identification of either individual harmonious craniofacial features or anomalous deviations from the individual norm. The use of cephalometric floating norms in the deciduous dentition phase is strongly recommended for early diagnosis and treatment planning.

Craniofacial changes induced by early functional treatment of Class III malocclusion.

To evaluate the effects of a functional appliance (removable mandibular retractor) on the craniofacial skeleton in children with Class II malocclusions, a longitudinal cephalometric study was performed. A sample of 30 children with treated Class III malocclusions (18 boys, 12 girls, mean age at the first observation 5.64 +/- 1.01 years, mean age at the second observation 8.43 +/- 1.73 years) was compared to a sample of 30 children with untreated Class III malocclusions (13 boys, 17 girls, mean age at first observation 6.06 +/- 1.14 years, mean age at the second observation 8.45 +/- 1.79 years) used as controls. The treated group matched the control group as to sex, age at the first observation, age at the second observation, observation period, Class III occlusal signs, and also as to angular craniofacial dimensions at the first observation. A cephalometric analysis based on a stable basicranial reference system was applied. The main significant findings in the treated group were an anterior morphogenetic rotation of the mandible as a result of an upward-forward direction of condylar growth, a more vertical orientation of the ramus, and a reduced gonial angle; reduced mandibular protrusion and total length; increased maxillary protrusion; increased maxillary dentoalveolar protrusion and reduced mandibular dentoalveolar protrusion. No significant changes in the vertical craniofacial relationships and in cranial base angulation were observed. The role of an early correction of Class III occlusal relationship in the establishment of a more favorable craniofacial growth pattern was discussed.

Mandibular skeletal changes induced by early functional treatment of Class III malocclusion: a superimposition study.

A superimposition study on mandibular stable structures was performed to evaluate changes in mandibular rotation and in the direction of condylar growth induced by early treatment of Class III malocclusion by a functional appliance (removable mandibular retractor). A sample of 18 children with treated Class III malocclusions, mean age at the first observation (immediately before the beginning of treatment) 5.47 +/- 1.14 years, mean age at the second observation 8 +/- 1.29 years, mean observation period 2.5 +/- 0.9 years, was compared with a control group of 18 children with untreated Class III malocclusions, mean age at the first observation 5.72 +/- 1.11 years, mean age at the second observation 7.86 +/- 1.44 years, mean observation period 2.27 +/- 0.92 years. No statistically significant difference between the two groups was recorded for positional (total) rotation of the mandible. A significant upward-forward direction of condylar growth was assessed in the treated group (p < 0.001). This therapeutically induced change in growth direction of the mandibular condyle was considered a skeletal sign of anterior morphogenetic rotation of the mandible, i.e., a mechanism compensating for excessive mandibular growth.

Identification and localization of endothelin-1 and its receptors in human fetal jaws.

In the mouse, disruption of the endothelin-1 (ET-1) gene causes severe craniofacial deformities, including mandibular hypoplasia. Since the phenotype of ET-1-deficient mice shows features in common with inherited human mandibulofacial dysostosis, we investigated the presence of ET-1 and its receptors in human fetal craniofacial tissues of 9- to 12-week-old fetuses. We found that ET-1 is immunolocalized in the epithelial cells of the oral cavity. Radioligand binding studies indicate the presence of elevated concentrations of both ETA and ETB receptors in membranes derived from fetal jaws. Using autoradiography, 125I-ET-1 binding sites were shown to be localized within the embryonic mandibular process of the oral cavity, where they were confined to the mesenchymal-derived osteogenic cells. Our data suggest a role for ET-1 in the development of the human mandible.

Primary tooth ankylosis: report of case with histological analysis.

Two primary molars in infraclusion showing clinical and radiographic signs of ankylosis, were subject to histological examination by bright field and polarization microscopy. The roots revealed signs of ongoing resorptive and reparative processes and in some areas dentin with signs of resorption-or repair cementum-were fused with simple lamellar or osteonic bone. These results suggest that ankylosis of primary molars can result from a disturbance of root resorption, with repair processes prevailing over resorptive ones and leading to excessive deposition of bone besides cementum-as a consequence of bone-inductive properties of dentin.

Class III malocclusion in the deciduous dentition: a morphological and correlation study.

The craniofacial morphology of Class III children with a full deciduous dentition was investigated by means of a cephalometric and correlation study. A group of 69 Class III subjects was compared to a group of 60 Class I subjects during the phase of the primary dentition. Each group was then divided into three age subgroups (4, 5, and 6 years) and a comparison was also performed between Class III and Class I subgroups. According to the results, early signs of Class III skeletal disharmony are present during the deciduous dentition phase. A larger mandibular body length (P < 0.001), a greater value for the ratio between the extent of the anterior cranial base and the mandibular body length (P < 0.001), and a forward positioning of the mandible (< P0.01 < 0.001) were consistently found in Class III children at the ages of 4, 5, and 6 years. A correlation analysis between all the cephalometric measurements in the Class III and Class I groups was then carried out, and the significance of the differences between correlation coefficients of the two groups was calculated. A distinctive Class III pattern of non-topographical associations between anterior cranial base and mandibular measurements could be detected.

Dental and craniofacial findings in hypohidrotic ectodermal dysplasia during the primary dentition phase.

A more detailed knowledge of dental and craniofacial features in hypohidrotic ectodermal dysplasia (HED) during childhood is needed in order to include these characteristics among diagnostic criteria. The present study comprised 5 HED children, 4 males and 1 female, during the primary dentition phase. Clinical and radiological dental findings consisted of multiple congenitally missing primary teeth, conoid primary incisors, moderate to severe taurodontic second primary molars. Supernumerary cusps and diastema were found as well. A pattern of symmetry was assessed for hypodontia in the primary dentition. The cephalometric study compared the HED sample to a matched non-syndrome sample and revealed abnormally short maxillary depth (p < 0.05), strongly reduced lower facial height (p < 0.01) and a reduction in facial soft tissue thickness (p < 0.05 - p < 0.01) in HED children. The importance of an early diagnosis and treatment of HED dento-facial malformations so as to improve esthetics and function is stressed.

Dental and craniofacial findings in a child affected by glycogen storage disease type III.

This paper reports on previously undescribed dentofacial features a child suffering from Glycogen-Storage Disease type III with hepatomegaly and hypertransaminasemia with muscular involvement. Deficient craniofacial development, reduced width of the upper jaw resulting in posterior cross-bite, and taurodontism of the primary dentition were found. Pathogenetic basis for craniofacial abnormalities is discussed. Cooperation between pediatricians and pediatric dentists is strongly recommended for an early diagnosis and treatment of the dentofacial defects of the syndrome.

[A current update on the etiopathogenesis of palatoschisis]. / Attuali orientamenti sulla etiopatogenesi della palatoschisi.

By means of a review of the most recent literature, the authors report on "state of the art" about etiology and pathogenesis of cleft palate. Epithelial-mesenchymal interactions regulating growth and orientation of palatal shelves, as well as teratogenic effects on such ultrastructural development control by endogenous and exogenous substances, are described.

Microscopical aspects of root resorption of human deciduous teeth.

In order to obtain detailed information on the tissue changes which occur during physiological root resorption, 52 human deciduous teeth at various stages of resorption were studied under light microscopy. The early stage of root resorption was defined as resorption of not more than one third of the root length; the late stage was defined as resorption of more than one third. A close topographical interrelationship was found among che sites of pressure of the permanent tooth, the extent of root resorption and the types of tissue changes. Linear resorption (which reflects suspension or marked slowing down of resorption) and redeposition of hard tissue were more pronounced at the early stage of resorption, while lacunar resorption was more pronounced at the late stage. There were pronounced haemorrhagic and inflammatory infiltrates within the pulp at the late stage of resorption and the subodontoblastic cells disappeared as the infiltrates took over the tooth. False denticles were found frequently, especially at the early stage of resorption. Unexpectedly, acellular cementum was found to be deposited against secondary dentine at the cuspidal tip of the pulp chamber of seven teeth, independently of any sign of resorption nearby. These data indicate that: 1) the pressure exerted by a permanent tooth is the most important factor in the differentiation of odontoclasts. 2) the extent of lacunar (i.e., active) resorption correlates directly with the resorption rate, which is higher at the late stage of root resorption. 3) inflammation is a consequence, rather than a cause, of resorption; it may lead to the loss of subodontoblastic cells and a consequent decrease in the ability of the pulp cells to replace damaged odontoblasts. 4) the pulp of the deciduous tooth might be cementogenic in some way, given that about 13% of the samples were found to be so.