[Growth and dental implants: assessment and prevention of the long-term aesthetic risk]. / Croissance et implants dentaires : évaluation et prévention du risque esthétique.

Using implant to replace a tooth is a well known treatment. However, the practitioner must keep in mind that osteointegrated implants behave like ankylosed teeth, and their evolution does not follow the alveolar processes of the adjacent teeth during growth. This growth decreases after 20 years, but remains present. This can lead to infraposition functionally and aesthetically failure for the implant therapy. Risk factors, like patient's age, sex and shape of the face must be evaluated. Most palatal implant positioning and use of screwed prosthetic tooth can permit the infraposition treatment during years of aging.

Diagnostic performance of various cephalometric parameters for the assessment of vertical growth pattern.

INTRODUCTION: Multiple cephalometric analyses are used to diagnose vertical skeletal facial discrepancy. A multitude of times, these parameters show conflicting results, and a specific diagnosis is hard to reach. OBJECTIVE: Hence, this study aimed to identify the skeletal analysis that performs best for the identification of vertical skeletal pattern in borderline cases. METHODS: The sample consisted of 161 subjects (71 males and 90 females; mean age = 23.6 ± 4.6 years). Y-axis, Sella-Nasion to mandibular plane angle (SN.MP), maxillary plane to mandibular plane angle (MMA), Sella-Nasion to Gonion-Gnathion angle (SN.GoGn), Frankfort to mandibular plane angle (FMA), R-angle and facial height ratio (LAFH.TAFH) were used to evaluate vertical growth pattern on lateral cephalograms. The subjects were divided into three groups (hypodivergent, normodivergent and hyperdivergent groups), as indicated by the diagnostic results of the majority of parameters. Kappa statistics was applied to compare the diagnostic accuracy of various analyses. To further validate the results, sensitivity and positive predictive values (PPV) for each parameter were also calculated. RESULTS: SN.GoGn showed a substantial interclass agreement (k = 0.850). In the hypodivergent group, MMA showed the highest sensitivity (0.934), whereas FMA showed the highest PPV (0.964). In the normodivergent group, FMA showed the highest sensitivity (0.909) and SN.GoGn had the highest PPV (0.903). SN.GoGn showed the highest sensitivity (0.980) and PPV (0.87) in the hyperdivergent group. CONCLUSIONS: SN.GoGn and FMA were found to be the most reliable indicators, whereas LAFH.TAFH is the least reliable indicator in assessing facial vertical growth pattern. Hence, the cephalometric analyses may be limited to fewer analyses of higher diagnostic performance.

Diagnostic performance of various cephalometric parameters for the assessment of vertical growth pattern

ABSTRACT Introduction: Multiple cephalometric analyses are used to diagnose vertical skeletal facial discrepancy. A multitude of times, these parameters show conflicting results, and a specific diagnosis is hard to reach. Objective: Hence, this study aimed to identify the skeletal analysis that performs best for the identification of vertical skeletal pattern in borderline cases. Methods: The sample consisted of 161 subjects (71 males and 90 females; mean age = 23.6 ± 4.6 years). Y-axis, Sella-Nasion to mandibular plane angle (SN.MP), maxillary plane to mandibular plane angle (MMA), Sella-Nasion to Gonion-Gnathion angle (SN.GoGn), Frankfort to mandibular plane angle (FMA), R-angle and facial height ratio (LAFH.TAFH) were used to evaluate vertical growth pattern on lateral cephalograms. The subjects were divided into three groups (hypodivergent, normodivergent and hyperdivergent groups), as indicated by the diagnostic results of the majority of parameters. Kappa statistics was applied to compare the diagnostic accuracy of various analyses. To further validate the results, sensitivity and positive predictive values (PPV) for each parameter were also calculated. Results: SN.GoGn showed a substantial interclass agreement (k = 0.850). In the hypodivergent group, MMA showed the highest sensitivity (0.934), whereas FMA showed the highest PPV (0.964). In the normodivergent group, FMA showed the highest sensitivity (0.909) and SN.GoGn had the highest PPV (0.903). SN.GoGn showed the highest sensitivity (0.980) and PPV (0.87) in the hyperdivergent group. Conclusions: SN.GoGn and FMA were found to be the most reliable indicators, whereas LAFH.TAFH is the least reliable indicator in assessing facial vertical growth pattern. Hence, the cephalometric analyses may be limited to fewer analyses of higher diagnostic performance.

RESUMO Introdução: diferentes análises cefalométricas são utilizadas para se diagnosticar a discrepância esquelética vertical da face. Muitas vezes, essas análises revelam resultados conflitantes, tornado complicado obter um diagnóstico preciso. Objetivo: o objetivo do presente estudo foi identificar a melhor análise esquelética para identificação do padrão esquelético vertical em casos limítrofes. Métodos: a amostra consistiu em 161 indivíduos (71 homens e 90 mulheres, com idade média de 23,6 ± 4,6 anos). Para avaliar o padrão de crescimento vertical em telerradiografias de perfil, foram utilizados: o eixo Y, o ângulo formado entre a linha sela-násio e o plano mandibular (SN.MP), ângulo formado pelos planos maxilar e mandibular (MMA), ângulo formado pelas linhas sela-násio e gônio-gnátio (SN.GoGn), ângulo formado pelo plano de Frankfort e o plano mandibular (FMA), o ângulo R, e a proporção de altura facial (AFAI.AFAT). Os indivíduos foram divididos em três grupos (hipodivergente, neutro e hiperdivergente), em acordo com os resultados diagnósticos da maioria dessas medidas. A análise estatística Kappa foi empregada para comparar a precisão diagnóstica das diferentes análises. Para uma validação adicional dos resultados, também foram calculados, para cada medida, a sensibilidade e os valores preditivos positivos (VPP). Resultados: o SN.GoGn apresentou um valor alto de concordância interclasses (k = 0,850). No grupo hipodivergente, o MMA apresentou a maior sensibilidade (0,934), enquanto o FMA apresentou o VPP mais alto (0,964). No grupo neutro, o FMA apresentou a maior sensibilidade (0,909), enquanto o SN.GoGn apresentou o VPP mais alto (0,903). No grupo hiperdivergente, o SN.GoGn apresentou a maior sensibilidade (0,980) e o valor mais alto de VPP (0,87). Conclusões: constatou-se que, para avaliação do padrão de crescimento facial vertical, o SN.GoGn e o FMA foram os indicadores mais confiáveis, enquanto o AFAI.AFAT foi o indicador menos confiável. Sendo assim, a análise cefalométrica pode se limitar às análises com maior desempenho diagnóstico.

The inadequacy of the Y-axis of growth (SNGn) for the vertical pattern assessment in patients with sagittal discrepancies.

AIM: The aim of this cephalometric study was to evaluate the influence of the sagittal skeletal pattern on the 'Y-axis of growth' measurement in patients with different malocclusions. MATERIALS AND METHODS: Lateral head films from 59 patients (mean age 16y 7m, ranging from 11 to 25 years) were selected after a subjective analysis of 1630 cases. Sample was grouped as follows: Group 1 - class I facial pattern; group 2 - class II facial pattern; and Group 3 - class III facial pattern. Two angular measurements, SNGoGn and SNGn, were taken in order to determine skeletal vertical facial pattern. A logistic regression with errors distributed according to a binomial distribution was used to test the influence of the sagittal relationship (Class I, II, III facial patterns) on vertical diagnostic measurement congruence (SNGoGn and SNGn). RESULTS: RESULTS show that the probability of congruence between the patterns SNGn and SNGoGn was relatively high (70%) for group 1, but for groups II (46%) and III (37%) this congruence was relatively low. CONCLUSION: The use of SNGn appears to be inappropriate to determine the vertical facial skeletal pattern of patients, due to Gn point shifting throughout sagittal discrepancies. Clinical Significance: Facial pattern determined by SNGn must be considered carefully, especially when severe sagittal discrepancies are present.

Cephalometric assessment of human fetal head specimens.

BACKGROUND: Past investigations of prenatal craniofacial growth have largely relied on histological sections. Few studies have taken measurements on three-dimensional representations (3D reconstruction, 3D CT, postmortem) or varying depth levels (ultrasound), and we know of no craniofacial growth studies done on cleared-and-stained specimens of whole fetal heads. MATERIALS AND METHODS: This study comprised 14 human fetal head specimens cleared and stained with alizarin red and alcian blue. They had been stored in glycerol and represented weeks 8-12 of gestation, with crown-rump lengths ranging from 23-145 mm. These specimens were cephalometrically analyzed in norma frontalis and norma lateralis, which notably included the opportunity for side-to-side comparison. RESULTS: As the cranial membrane bones progressively approached each other, the orbits, maxilla, and mandible gradually grew wider. Likewise, the sagittal dimensions of the maxilla and mandible increased continuously and synchronically. We noted side-to-side differences ranging from 2-5 mm. Another notable finding concerned the inclination of the maxilla relative to the cranial base, which increased more on the right than on the left side. CONCLUSION: This is the first investigation presenting side-to-side comparative measurements of human fetal head specimens. Such measurements are essential in the quest toward validating the findings of other imaging techniques such as CT or MRI and-most importantly-intrauterine sonography.

One-stage cleft repair outcome at age 6- to 18-years -- a comparison to the Eurocleft study data.

The optimisation of the relation between quality of outcome and burden of care is difficult in the treatment of cleft lip and palate. We analysed long-term outcome after one-stage repair of clefts to assess the benefits and limitations of this form of treatment. Thirty-three patients aged 6-18 years who had had lip repair, two-flap palatoplasty, and corticocancellous alveolar bone grafts at 6 months of age were divided into three age groups (6-11, 12-14, and 15-18 years) and compared with mean outcome data from the Eurocleft centres and with cephalometric standards of healthy people. Fifteen of the 33 patients were assessed for nasalance. Maxillary protrusion (SNA) and intermaxillary relation (ANB) in the one-stage groups differed significantly from those of healthy people, but not from corresponding means in the Eurocleft study. In 61% the Bergland score for alveolar ossification was grade I or II, and in 15% it was grade III; 24% had secondary alveolar bone grafting. No palatal fistulas occurred and nasalance did not differ significantly from that of healthy controls. As each patient generally had a primary operation and one secondary procedure, they benefited from half the number of surgical steps of multistage procedures. However, one-stage procedures led to significant disturbance in growth, but the degree of this was similar to mean values of multistage procedures in the Eurocleft study. Primary alveolar bone grafting led to inconsistent alveolar ossification and was suspected to interfere with anterior maxillary growth so it has been abandoned.

Spatially-dense 3D facial asymmetry assessment in both typical and disordered growth.

Mild facial asymmetries are common in typical growth patterns. Therefore, detection of disordered facial growth patterns in individuals characterized by asymmetries is preferably accomplished by reference to the typical variation found in the general population rather than to some ideal of perfect symmetry, which rarely exists. This presents a challenge in developing an asymmetry assessment tool that is applicable, without modification, to detect both mild and severe facial asymmetries. In this paper we use concepts from geometric morphometrics to obtain robust and spatially-dense asymmetry assessments using a superimposition protocol for comparison of a face with its mirror image. Spatially-dense localization of asymmetries was achieved using an anthropometric mask consisting of uniformly sampled quasi-landmarks that were automatically indicated on 3D facial images. Robustness, in the sense of an unbiased analysis under increasing asymmetry, was ensured by an adaptive, robust, least-squares superimposition. The degree of overall asymmetry in an individual was scored using a root-mean-squared-error, and the proportion was scored using a novel relative significant asymmetry percentage. This protocol was applied to a database of 3D facial images from 359 young healthy individuals and three individuals with disordered facial growth. Typical asymmetry statistics were derived and were mainly located on, but not limited to, the lower two-thirds of the face in males and females. The asymmetry in males was more extensive and of a greater magnitude than in females. This protocol and proposed scoring of asymmetry with accompanying reference statistics will be useful for the detection and quantification of facial asymmetry in future studies.

Cephalometric superimposition on the occipital condyles as a longitudinal growth assessment reference: I-point and I-curve.

This retrospective study tests the hypothesis that superimposition referenced at the occipital condyles (defined as I-point, I-curve) and oriented to the anterior cranial base (ACB) will display a growth pattern that is more consistent with independent evaluations, such as the Melsen necropsy specimens and the Bjork implant studies, when compared with traditional superimpositions referenced at sella turcica. Twenty-eight sets of serial lateral cephalometric radiographs were selected from an archived growth study. The apparent facial growth was compared using polar coordinate analysis from superimposition tracings of the serial films for each subject. The two superimposition methods were compared. The traditional method, ACB registered on the anterior curvature of sella turcica, versus registration on I-point while maintaining ACB parallel. I-point registered superimpositions consistently displayed a facial growth pattern that was more consistent with the classic necropsy specimens of children and the cephalometric studies superimposing on implant markers. Traditional ACB superimposition suggests that airway is restricted by normal growth. This apparent physiologic artifact does not occur when superimpositions are registered on I-point. Sella turcica displays vertical movement that is consistent with brain growth. These data indicate that registration on I-point is a more accurate physiologic representation of facial growth than the traditional ACB superimpositions. When compared with the traditional registration at sella turcica, I-point superimposition better elucidates physiologic growth patterns. As cephalometrics evolve from a two to a three dimensional science, it is important to use a more biologically valid registration for evaluating therapeutics and facial growth patterns.

Cephalometric assessment of dentofacial vertical changes in Class I subjects treated with and without extraction.

INTRODUCTION: There is disagreement concerning the effect of premolar extractions on the dentofacial vertical dimension. It has been suggested that orthodontic forward movement of the posterior teeth after first premolar extraction leads to reduction in vertical dimension. The purpose of this study was to examine cephalometrically the dentofacial vertical changes in Class I Indian subjects treated with and without extractions. METHODS: The extraction group included 31 normodivergent patients (26 female, 5 male; pretreatment age, 17.19 +/- 3.89 years) with maxillary and mandibular first premolar extractions. The nonextraction group included 29 patients (18 female, 11 male; pretreatment age, 18.48 +/- 3.61 years). A coordinate system with the Frankfort horizontal plane and a mandibular fiduciary line was used for the cephalometric calibration. To determine vertical dimension changes due to treatment and to compare differences between the 2 groups, paired and unpaired t tests were performed, respectively. RESULTS: Both groups had increases in linear vertical dimensions (P <0.05), but the change was comparatively greater in the extraction group (P <0.05). Mesial movement of the maxillary and mandibular posterior teeth was coincidental with the extrusion to such an extent that it increased the vertical dimension, although the mandibular plane angle remained unchanged during treatment. CONCLUSIONS: Extraction of teeth only to increase the overbite or decrease the mandibular plane angle might not be justified.

A long-term retrospective outcome assessment of facial growth, secondary surgical need, and maxillary lateral incisor status in a surgical-orthodontic protocol for complete clefts.

In 1965, the cleft palate team at Children's Memorial Hospital embarked on a new surgical-orthodontic protocol in the habilitation of newborn complete cleft lip and palate cases. It brought the orthodontic effort into focus at birth and in planned sequence to correspond with the surgical procedures of lip closure, maxillary alveolar stabilization by means of an autogenous graft of the authors' design, and complete palate closure, all within the first year of life. The purpose of this investigation is threefold: first, to review the authors' previous publications and assess growth, secondary surgical need, and lateral incisor status of teeth adjacent to the cleft in a series of patients who have all followed a precise, early surgical/orthodontic protocol; second, to compare these cases with other collaborative studies wherein this protocol was not used; and third, to report on an additional 82 cases with regard to secondary surgical need and the status of teeth adjacent to the cleft. Methods of assessment have included cephalometric radiography, periapical and occlusal dental radiography, computer-assisted tomography, plaster cast analysis, and intraoral and extraoral photography. The authors have demonstrated, along with other collaborative studies, that there is growth as good as other similar samples wherein there was no primary osteoplasty. In addition, the authors found their incidence of orthognathic surgery to be 18.29 percent; pharyngoplasty, 3.65 percent; and oronasal fistulas requiring surgical closure, 29.27 percent. In the case of unilateral complete clefts, 53.13 percent of those lateral incisors present adjacent to the cleft area were usable, and in bilateral cases, 57.77 percent were usable. The authors remain convinced after more than 35 years of following this successful protocol that early maxillary orthopedics and their technique of primary osteoplasty in planned sequence with lip and palate closure can produce a more favorable alignment of maxillary growth potential and, with comprehensive orthodontic treatment, can lead to teeth in a better overall occlusion than if these procedures had not been undertaken.

Repair of the immature craniofacial skeleton with a calcium phosphate cement: quantitative assessment of craniofacial growth.

The potential for growth restriction has limited the use of alloplastic materials for reconstruction of the growing craniofacial skeleton. A calcium phosphate cement that has been introduced recently for craniofacial reconstruction crystallizes in situ into a substance that resembles more closely the mineral phase of bone, thereby offering the potential for enhanced bioresorption and osteoconductivity. The purpose of these experiments was to assess quantitatively craniofacial growth after reconstruction of frontal craniectomy defects in skeletally immature animals with this calcium phosphate bone mineral substitute. To simulate the calvarial defects that result from unilateral fronto-orbital advancement procedures, unilateral frontal bone flaps were removed in 3-week-old female Yorkshire piglets. The bone flaps were trimmed medially and posteriorly, and were then reattached to the supraorbital ridge. The resulting 5-mm gap between the frontal bone flap and the native bone was either filled with Norian CRS bone cement (N = 3) or left empty (N = 3). After 90 days, the animals were killed and the skulls were harvested and cleared. Direct craniometric measurements were performed on the prepared dry skulls to assess craniofacial growth in all dimensions. Extensive remodeling was observed within defects treated with the calcium phosphate cement, with complete or near-complete replacement of the cement by host bone, resulting in a solid bony union. Direct craniometric measurements revealed no differences in craniofacial growth in any dimension between the operated and unoperated sides of the cranium in either group. These studies demonstrate that craniofacial growth is not restricted after reconstruction of frontal craniectomy defects with carbonated calcium phosphate cement in skeletally immature animals. The remodeling capacity of this material offers promise for its safe use in reconstruction of the growing calvarium.

The reliability of 3 sagittal reference planes in the assessment of Class I and Class III treatment.

The objective of this study was to test the reproducibility and validity of 3 sagittal reference planes with the use of the Wits analysis. Measurements made to the functional occlusal plane, the bisected occlusal plane, and the maxillomandibular bisector were compared with each other and with the angular measurement of the ANB angle. The angular relationship of these reference planes to the postmaxillary vertical reference plane was also studied. The data were collected from pretreatment (T1), posttreatment (T2), and 2-year postretention (T3) lateral cephalograms of 35 Class I and 10 Class III subjects. Nonextraction treatment for these patients was performed with full fixed orthodontic appliances in the permanent dentition. Cephalometric data were compared with 39 Class I and 9 Class III control subjects. The serial lateral cephalograms of untreated control subjects that were analyzed were taken at ages approximating those of the treated groups at T1, T2, and T3. The maxillomandibular bisector was determined to be an easily identifiable and reproducible reference plane that exhibited greater stability over time with both growth and treatment than either the functional occlusal plane or bisected occlusal plane. The mean values for the maxillomandibular bisector Wits result for Class I and III populations were distinct and, when combined with previous Class II data, yielded a triphasic distribution that may be a useful clinical tool for patient assessment.

[Decision strategies in orthognathic surgery. Part 1: The predominance of functional factors in the choice of osteotomy sites. A theoretical study]. / Stratégie de la décision en chirurgie orthognathique. 1ère partie: prédominance des facteurs fonctionnels dans le choix des sites d'ostéotomie. Etude théorique.

Most of the scientific papers concerning facial osteotomies are focused on the surgical procedures. However, the most important thing to consider is how to go to the right indication and not how to do it. By an only morphological approach, as we can do with dental casts and cephalometric studies, it is obvious that we forget the functional factors. They nevertheless are essential to consider. Their knowledge permits understanding the physiopathology of the deformity and avoiding the postsurgical relapses. The main five factors concern: the dentoalveolar corridor, between tongue and orbicularis oris muscle, the facial bone growth modeling by functional matrix, the relations between upper incisors, lower incisors and lips, the posterior airway and the rest position of the tongue, the vertical muscular balance. Surgery has to normalize the abnormal function which is at the origin of the abnormal morphology. For this reason, maxillary surgery is better than mandibular surgery for the correction of a Class III deformity. Moreover, the transversal and vertical dimensions are always to be considered at the light of the functional parameters. Most of cases of dentofacial deformities are to be treated by bimaxillary osteotomies, including often transversal and/or vertical modifications. When the anatomical sites of these surgical procedures are determined, then we have to make an aesthetic facial profile simulation to validate the total amount of the bone displacements (cf. Part 2).

[Assessment of dentofacial growth changes using quadrilateral analysis].

This study was investigated to demonstrate the normal standards of the quadrilateral analysis and thereafter to clarify the mode of growth change by assessment of skeletal, dental and soft tissue proportion by the means of quadrilateral analysis. The materials used in this study consisted of cephalograms of 30 girls with normal occlusion. Cephalograms were taken longitudinally from first year grade of elementary school to third year grade of middle high school. For the group of each year grade, mean facial diagram, mean values of conventional cephalometric analysis and those of quadrilateral analysis were made, and compared and discussed for each other. The results were as follows: 1) The mandible grows forward with the decrease of gonial angle and forward rotation of mandibular plane. 2) In quadrilateral analysis, both jaws grow proportionally to the 6 year grade of elementary school, and after then mandible grows more forward than maxilla. 3) Though occlusal plane tended to rotate counterclockwisely to the palatal plane, it fell at right angle with A'B'. 4) Upper centrals tended to incline labially to the cranial base from first year grade to 6 year grade of elementary school and after that stage it remained stable. Lower centrals varied to third year grade of elementary school, but after that stage it remained stable. 5) Distances of upper and lower incisors to A'B' showed comparatively constant increase after the full eruption of permanent incisors. 6) Distance of nose tip to A'B' increased the most in the soft tissue landmarks. Subnasale soft pogonion line was considered to be effective base line of soft tissue profile because the angle with A'B' was stable along the growth and the distances of that to upper and lower lips were stable.