Palatal Plane Angle Research Articles

VERTICAL AND HORIZONTAL STABILITY FOLLOWING LE FORT I OSTEOTOMY WITHOUT BONE GRAFT

objectives: the study aimed to evaluate the vertical and horizontal stability following Le Fort I osteotomy without using any bone graft in patients with maxillary advancement up to 6 mm alone or combined with vertical repositioning. Patients and methods: patients referred for one piece Le Fort I osteotomy with or without other orthognathic procedures were included in this study. In all surgeries, the maxilla was fixed using titanium plates and no bone graft was used in any of the patients. Suspension wires were fixed to be used for IMF with elastics postoperatively. Lateral cephalometric X-rays were taken 1 week after the surgery (T1), and 1 year after the surgery (T2), these X-rays were used to evaluate the postoperative stability using the SNA angle, maxillary depth angle, palatal plane angle, and maxillary height angle to evaluate changes in the horizontal and vertical direction. results: The lateral cephalometric analysis for relapse in the anteroposterior direction showed that only 6 patients out of 18 (33.3%) encountered a relapse of more than 2° in SNA angle and 5 (27.7%) in the maxillary depth angle measurements. Yet in between those patients there was only one (5.5%) out of 18 patients had only maxillary advancement without vertical repositioning. The results of the maxillary height and palatal plane angles showed that all the changes of more than 2° in the vertical direction were in the elongation group (3 patients out of four) (75%) using the palatal plane angle while it was only 1 patient (25%) using the maxillary height angle evaluation. Conclusion: within the limitation of the present study (small sample number especially in the patients with vertical repositioning) ; the study suggests that the use of bone graft can be avoided in maxillary advancement movement up to 6 mm anterior repositioning even this was combined with superior repositioning. Moreover the study recommends the use of bone graft in cases of anterior maxillary advancement with inferior repositioning of the maxilla.

Long-term orthognathic surgical outcomes in Treacher Collins patients

Treacher Collins syndrome is a rare disorder characterized by several orofacial findings including malar deficiency and hypoplastic mandibles. These patients often require a combined orthodontic-orthognathic approach to correct their malocclusion. This is most often characterized by a short posterior vertical height and an anterior open bite. Orthognathic correction often requires Le Fort I and bilateral sagittal split osteotomies. No long-term stability results have been reported after bimaxillary surgery in Treacher Collins patients. A retrospective review of all Treacher Collins patients evaluated for orthognathic surgery by a single surgeon from 1993 to 2007 was performed. Patients were divided into groups who required surgery and those who did not. Part I analyzed the cephalometric differences between the surgical (S) and nonsurgical (NS) groups. Part II of the study assessed the preorthodontic treatment (T1), preoperative (T2), immediate postoperative (T3), and 1-year postoperative (T4) cephalometric measurement variables to determine the net surgical movement (T3 - T2) and relapse (T4 - T3). Twenty-two patients met the inclusion criteria, of which 11 had occlusal relationships requiring orthognathic surgery. Nine out of 11 chose to have surgery. At baseline, surgical patients exhibited a statistically significant retruded maxilla as measured by SNA and midface length compared to the NS group. In addition, the S group also had an increased gonial angle. There were significant movements in all maxillary and mandibular measurements. There was a significant relapse in the palatal plane angle when the maxilla was anteriorly impacted, with a 2.8-mm average relapse of the advancement. Relapse of the counterrotation movement of the mandible was identified, but this was not significant. Relapse did not affect the final occlusal result, which may have been compensated with postsurgical orthodontic treatment. Bimaxillary orthognathic surgery in the Treacher Collins patients may be performed safely with long-term dental and skeletal stability.

Residents' journal review

Residents' journal review

Alveolar bone thickness around maxillary central incisors of different inclination assessed with cone-beam computed tomography.

ObjectiveTo assess the labial and lingual alveolar bone thickness in adults with maxillary central incisors of different inclination by cone-beam computed tomography (CBCT).MethodsNinety maxillary central incisors from 45 patients were divided into three groups based on the maxillary central incisors to palatal plane angle; lingual-inclined, normal, and labial-inclined. Reformatted CBCT images were used to measure the labial and lingual alveolar bone thickness (ABT) at intervals corresponding to every 1/10 of the root length. The sum of labial ABT and lingual ABT at the level of the root apex was used to calculate the total ABT (TABT). The number of teeth exhibiting alveolar fenestration and dehiscence in each group was also tallied. One-way analysis of variance and Tukey's honestly significant difference test were applied for statistical analysis.ResultsThe labial ABT and TABT values at the root apex in the lingual-inclined group were significantly lower than in the other groups (p < 0.05). Lingual and labial ABT values were very low at the cervical level in the lingual-inclined and normal groups. There was a higher prevalence of alveolar fenestration in the lingual-inclined group.ConclusionsLingual-inclined maxillary central incisors have less bone support at the level of the root apex and a greater frequency of alveolar bone defects than normal maxillary central incisors. The bone plate at the marginal level is also very thin.

Molar heights and incisor inclinations in adults with Class II and Class III skeletal open-bite malocclusions

The aim of this research was to compare maxillary and mandibular molar heights and incisor inclinations in patients with skeletal open-bite Class II, patients with skeletal open-bite Class III, and an untreated control group. Pretreatment lateral cephalograms of 70 orthodontic patients (34 men, 36 women) between 16 and 40 years of age were examined. The sample was divided into 3 groups according to facial growth pattern and overbite. The control group (n= 25) included normodivergent Class I subjects with adequate overbite; the skeletal open-bite Class II group (n= 25) and the skeletal open-bite Class III group (n= 20) included hyperdivergent Class II or Class III subjects with negative overbite. Measurements considered were ANB angle, palatal and mandibular plane angles, maxillary incisor palatal plane angulation, and mandibular incisor mandibular plane angulation, as well as the distance from the palatal or the mandibular plane to the mesial cusp of the molars. Multivariate analysis of covariance and multivariate analysis of variance tests were used to determine the differences between the groups, followed by the Tukey post-hoc test. Additionally, the Mann-Whitney U test and Kruskall-Wallis test were performed. Significant differences in molar height were found (P<0.001). A 4-mm difference in maxillary molar height between the skeletal open-bite and control groups was found. Mandibular molar height was greater in the skeletal open-bite Class II group (P<0.001). Maxillary incisor palatal plane angulation was greater in the skeletal open-bite Class III group by approximately 6°. Mandibular incisor to mandibular plane angulation was 10° more lingual in the skeletal open-bite Class III group (P<0.001). The skeletal open-bite groups had greater molar heights than did the control group. The skeletal open-bite Class II group had more eruption of the mandibular molars. The maxillary incisors were more proclined and the mandibular incisors were more lingual in the skeletal open-bite Class III group.

The Wits appraisal among a Nigerian sub-population: an assessment of dental base geometric factors

The Wits appraisal is a common linear cephalometric analytic tool established by Jacobson. It has been reported to be superior to angular cephalometric measures as it is not dependent on pericranial structures and their variations both during growth and orthodontic treatment. Aim: To obtain reference values for the Wits appraisal among Nigerians and assess the effect of the dental base geometry on it. Methods: Lateral cephalometric radiographs of 100 Nigerian subjects with normal occlusion were analyzed to obtain the Wits appraisal, and the effect of the vertical distance from subspinale to supramentale, length of the palatal and mandibular planes, the mandibular plane angle as well as the palatal plane angle were assessed using the ANOVA and linear regression analysis. Results: The mean age was 20.69 ± 4.9 years. Thirty-four (34%) were males and 66(66%) were females. Mean Wits value of -3.43 ± 3.24 mm was obtained based on the functional occlusal plane (FOP). Linear regression analysis showed that the vertical height from subspinale (A point) to supramentale (B point) caused a significant change in the Wits appraisal reading in participants still undergoing active growth process (less than 16 years of age) (p=0.02). Conclusions: It is advocated that the Wits appraisal be used as a moderator to the ANB angle among Nigerians. However, as a result of dental height variations its use in growing Nigerian children requires caution.

Incidence and evaluation of open bite malocclusion and their management

Introduction: Open bite malocclusion is one of the most difficult dentofacial deformities to treat. Although this type of malocclusion can occur unilaterally or bilaterally in the buccal segments. It is mostly seen in the anterior segment where there is no incisal contact and vertical overlap of the lower incisors by the uppers. Objectives: The study was aimed to find out the incidence of open bite malocclusion and their pre and post treatment evaluation of the treated cases and also compare the result of two study groups (skeletal open bite and dental open bite). Methods: A total number of 31 patients with open bite malocclusion out of 1372 patients reported to Department of Orthodontics, Dhaka Dental College and Hospital for treatment. Out of them 21 patients were included in this study with mean age 22±5.4, who successfully completed treatment. Of them 14 were included in the dental group and 07 in the skeletal group. Pre treatment history, clinical examination along with pre and post-treatment photographs, study models and lateral cephalograms were used to compare the treatment outcome between the two study groups. Results: The incidence of open bite was 2.3%. Out of 21 open bite samples 14 were of dental type and the rest 07 were of skeletal type. 47.6% open bite had Angles Class I malocclusion, 42.9% were Class II and 9.5% were Class III. Cephalometric analysis of vertical measurements showed that the mandibular plane angle, palatal plane angle and SNA angle significantly decreased from pre-treatment to post-treatment (p&lt;0.05) in both groups . Gonial angle remains unchanged. Cephalometric analysis of the linear and dental measurements showed increased upper face height, posterior facial height and inter-incisal angle. Soft tissue evaluation on cephalometry showed significant decrease of esthetic plane and interlabial gap. A statistically significant mean difference was found in case of negative overbites among the patients with dental group (p&lt;0.001). Less time was required for completion of treatment in dental group and prognosis was significantly better (p&lt;0.05) Conclusion: The result of the present study indicates that the treatment period and wear time of appliance in dental type was shorter than skeletal type. Both groups showed significant improvement though prognosis was better in dental type of open bite cases.DOI: http://dx.doi.org/10.3329/bjodfo.v2i2.16156 Ban J Orthod &amp; Dentofac Orthop, April 2012; Vol-2, No.2, 1-7

Orthodontic Treatment of Dental Open Bite in an Adult: A Case Report

Case report of an adult Bangladeshi male aged 26 years who complained about ineffective chewing of food and unpleasant aesthetic look. The patient was diagnosed to have a 4 mms of anterior dental open bite on skeletal Class I with normal mandibular plane and palatal plane angles. Treatment was orthodontics alone with non-extraction. The main mechanics used to close the anterior open bite, were by the conventional aligning, leveling and arch contraction by standard edgewise technique. The result showed that it was possible to correct the open bite within a short period; however, the appliance was difficult to clean. The treatment was complete after 2 years with positive overbite of 3 mms and acceptable occlusion. The patient was happy with his new appearance and function. DOI: http://dx.doi.org/10.3329/bjodfo.v1i1.15973 Ban J Orthod &amp; Dentofac Orthop, October 2010; Vol-1, No.1, 16-21

A Cephalometric Evaluation of Pretreatment and Post-treatment Outcome using Tetragon Analysis: A Retrospective Study

Few cephalometric analyses have been put forward to assess the treatment outcome after orthodontic treatment. However, these analyses are somewhat complicated and time consuming. The Tetragon analysis is introduced with measurement of treatment outcome as one of its objectives. The study was undertaken to evaluate the treatment outcome by checking the skeletal and dental changes using pretreatment and post-treatment radiographs and to evaluate the efficiency of treatment in the Department of Orthodontics, College of Dental Sciences, Davangere, using the Tetragon analysis. Records of 35 finished patients with fixed orthodontic therapy using preadjusted edgewise appliance were selected. The samples were analyzed separately for the skeletal parameters consisting of skeletal class I, II and III using Tetragon analysis. The post-treatment reduction of upper incisor palatal plane angle was found to be statistically significant in skeletal class I (p < 0.01) and skeletal class II patients (p < 0.05). The post-treatment increase in interincisal angle was found to be statistically significant in skeletal class I (p < 0.01) class II patients (p < 0.05). Fixed appliance therapy reduced the proclination of upper incisors and increased the interincisal angle in skeletal class I and II cases but not in skeletal class III cases. The lower incisal angulation and the maxilla-mandibular plane angle did change significantly and so were the angles of the Trigon. The Tetragon analysis proved easy to measure the treatment outcome.

Maxillary Yaw as the Primary Predictor of Maxillary Dental Midline Deviation: 3D Analysis Using Cone-Beam Computed Tomography

The purpose of this study was to investigate which factors affect upper dental midline deviation in dentofacial deformity patients using cone-beam computed tomography analysis. Twenty-eight patients were selected for this study. Subjects were divided into 2 groups according to the amount of upper incisor (U1) midline deviation from the clinical facial midline: group 1 (U1 deviation <2 mm) and group 2 (U1 deviation >2 mm). Linear measurements, angles, and reference planes on 3-dimensional (3D) computed tomograms were obtained. The predictor variables were maxillary yaw, palatal plane angle, differences of maxillary point to the coronal and sagittal planes, and maxillary canting. The outcome variable was U1 deviation. The variables between the 2 groups and 2 sides were analyzed with a t test. Pearson correlation coefficient and multiple regression analysis were also calculated within each group for each measurement against the U1 deviation to determine which variables affect U1 deviation. P < .05 was considered statistically significant. The patients were evenly distributed between each group (n = 14 in each group). There was significant deviation of U1 from the sagittal plane in group 2 compared with group 1 (0.99 mm in group 1 vs 1.73 mm in group 2, P < .05). When we compared yaw with the sagittal plane, group 2 was more rotated than group 1 (1.16° in group 1 vs 2.28° in group 2, P < .01). Through multiple regression analysis, the primary predictor variable for U1 deviation was maxillary yaw (P < .05). This study suggests that maxillary yaw is the primary contributing factor for upper dental midline deviation. The use of maxillary yaw should be considered when one is performing orthognathic surgery in patients with U1 deviation to achieve optimum esthetics.

Residents' journal review

Residents' journal review

Poster 41: Stability of Anterior Open Bite Correction in Class III Patients Using Bimaxillary Surgery Involving Intraoral Vertical Ramus Osteotomy

There is currently limited data on the use of intraoral vertical ramus osteotomy (IVRO) in the surgical treatment of anterior open bite and class three malocclusion. The purpose of this study is to investigate the stability of Le Fort I osteotomy with IVRO in the correction of anterior open bite with concomitant class III malocclusion. Chart reviews of patients who underwent surgical correction of anterior open bite with class three malocclusion were obtained from the years 2004-2009. Preoperative, postoperative, and 1 year postoperative lateral cephalograms were obtained. Anterior open bite was measured clinically from the edge of the maxillary central incisor to the edge of the mandibular central incisor along its axis. Angular measurements were used to evaluate jaw movement in the horizontal and vertical directions. Anterior-posterior movement of the jaws was determined by changes in the SNA and SNB angles. Vertical movements of the maxilla were calculated from changes in the Maxillary Occlusal Plane (MOP) and Palatal Plane (PP) angles to SN. Mandibular vertical movement was based on changes in the mandibular plane (MP) angle to SN. Dental compensation was determined by changes in MOP and MP angles. All cephalograms were traced and measured digitally with Dolphin© software. Statistical analysis was performed with the SAS procedure PROC MIXED (SAS/STAT software, SAS institute Inc., Cary, NC, USA). The accuracy of landmark identification, superimposition, and measurements were confirmed by retracing all cephalograms 7 days later by the same investigator. Sixty patient records were identified with 27 meeting the inclusion criteria. Six patients failed to have positive incisal overlap at 1 year postoperative (23%). Comparing preoperative data between the 2 groups, patients in the relapse group had a more significant open bite (OB −6.07 mm vs. −3.48 mm, p<0.05), overjet (−2.14 mm vs. −0.79 mm, p<0.05), maxillary posterior vertical excess (SN-PP: 0.75° vs. 3.74°, p<0.05), and a steeper mandibular plane angle (SN-MP: 41.98° vs. 36.35°, p<0.05). Surgically, the relapse group also had more maxillary clockwise movement compared to the non-relapse group (SN-PP +5.72° vs. +3.39°, p<0.05), but less mandibular counterclockwise movement (SN-MP −0.93° vs. −2.46°, p<0.05). When separating patients based on the severity of their preoperative open bite: no patients failed in the mild group (1–3 mm open bite; 0/9, 0%), 3 patients failed in the moderate group (3–6 mm open bite; 3/13, 23%), and 3 patients failed in the severe group (>6 mm open bite; 3/5, 60%). IVRO, when performed with maxillary Le Fort I osteotomy, has a success rate (78% positive incisal overlap at 1 year post operative) that is comparable to other surgical techniques when treating patients with anterior open bite and concomitant class III malocclusion. Patients likely to relapse have a severe preoperative open bite, a high preoperative mandibular plane angle, or inadequate mandibular counterclockwise movement during surgery. This study provides an evidence-based alternative to current techniques.

Comparison of craniofacial morphology, head posture and hyoid bone position with different breathing patterns

The aim of this study was to evaluate differences in craniofacial morphology, head posture and hyoid bone position between mouth breathing (MB) and nasal breathing (NB) patients. Mouth breathing patients comprised 34 skeletal Class I subjects with a mean age of 12.8±1.5years (range: 12.0-15.2years). Thirty-two subjects with skeletal Class I relationship were included in the NB group (mean 13.5±1.3years; range: 12.2-14.8years). Twenty-seven measurements (15 angular and 12 linear) were used for the craniofacial analysis. Additionally, 12 measurements were evaluated for head posture (eight measurements) and hyoid bone position (four measurements). Student's t-test was used for the statistical analysis. Probability values <0.05 were accepted as significant. Statistical comparisons showed that sagittal measurements including SNA (p<0.01), ANB (p<0.01), A to N perp (p<0.05), convexity (p<0.05), IMPA (p<0.05) and overbite (p<0.05) measurements were found to be lower in MB patients compared to NB. Vertical measurements including SN-MP (p<0.01) and PP-GoGn (p<0.01), S-N (p<0.05) and anterior facial height (p<0.05) were significantly higher in MB patients, while the odontoid proses and palatal plane angle (OPT-PP) was greater and true vertical line and palatal plane angle (Vert-PP) was smaller in MB patients compared to NB group (p<0.05 for both). No statistically significant differences were found regarding the hyoid bone position between both groups. The maxilla was more retrognathic in MB patients. Additionally, the palatal plane had a posterior rotation in MB patients. However, no significant differences were found in the hyoid bone position between MB and NB patients.

Combined Orthodontic and Orthognathic Surgical Treatment for the Correction of Skeletal Anterior Open-Bite Malocclusion: A Systematic Review on Vertical Stability

To evaluate vertical stability after combined orthodontic surgical treatment of skeletal anterior open-bite malocclusion. A literature search was performed to locate studies pertaining to vertical stability after combined orthodontic surgical treatment of skeletal anterior open-bite malocclusion. Data from the identified studies were extracted and assessed for quality. Short-term and long-term changes in the following variables were evaluated: overbite; mandibular plane, palatal plane, and intermaxillary angles; and anterior facial height. Nine studies, all retrospective, were appropriate for inclusion after review. The postoperative follow-up period ranged from 1 to 18 years. A wide variation was present for post-treatment changes and relapse. Dentally, overbite changes showed a wide variation, with more long-term relapse observed in patients after Le Fort I osteotomy. Skeletally, the mandibular plane and intermaxillary angles showed greater long-term relapse after bimaxillary surgery than after Le Fort I osteotomy. The same trend was seen for the post-treatment increase in anterior facial height. In contrast, the palatal plane seemed to remain rather stable. Vertical relapse is a characteristic in a certain number of patients after combined orthodontic surgical treatments regardless of surgery type. This can be observed dentally by an opening of the bite and skeletally by an increase in the mandibular plane and intermaxillary angles during long-term follow-up. Long-term skeletal relapse seems to be more common after bimaxillary surgery.

Pharyngeal Airway Changes Associated With Maxillary Distraction Osteogenesis in Adult Cleft Lip and Palate Patients

To investigate 1) the changes in pharyngeal airway sizes associated with maxillary distraction osteogenesis and 2) the correlations between maxillary skeletal variables and the pharyngeal airway in adult patients with cleft lip and palate. The study was carried out in 14 adult subjects with cleft lip and palate. Predistraction records were taken at a mean age of 22.7 ± 4.6 years. All patients had placement of a rigid external distraction device (RED I; KLS Martin, Tuttlingen, Germany) after Le Fort I osteotomy. Lateral cephalograms were assessed before surgery and at short-term follow-up (8.0 ± 6.4 months). The cephalometric skeletal and pharyngeal airway variables were statistically evaluated by use of the Wilcoxon signed-rank test. Spearman ρ correlation was performed to check the correlations between maxillary skeletal and pharyngeal variables. The maxillary movement was 8.7 mm (P < .01). The maxillary depth angle (+7.9°) and effective maxillary length (9.4 mm) increased significantly (P < .01) after distraction, whereas the palatal plane angle remained unchanged. Anterior nasal spine (8.2 mm) and Posterior nasal spine (6.9 mm) moved anteriorly. The overjet increased (9.5 mm) significantly (P < .01). Posterior, superoposterior, and middle airway spaces increased significantly, with mean differences of 7.5 mm, 5.1 mm, and 3.3 mm, respectively. The soft palate moved anteriorly, with the greatest movement at its superior point. Significant positive correlations were observed for the posterior and superoposterior airway spaces and maxillary movement. PNS changes showed the highest correlation with posterior airway changes. The significant anterior movement of the maxilla resulted in significant increases in posterior, superoposterior, and middle airway spaces. The posterior airway space showed the highest significant positive correlation with the movement of PNS. The posterior and superoposterior airway spaces also showed significant positive correlations with the maxillary skeletal variables.

Stability of maxillary advancement using external rigid distractors in cleft lip and palate patients

Purpose: To evaluate the skeletal changes associated with maxillary advancement using the external rigid distractor in cleft lip and palate patients after distraction and to assess the stability of these changes. Patients and Methods: Eight cleft lip and palate patients with maxillary hypoplasia underwent maxillary distraction osteogenesis using external rigid devise. Lateral cephalometric records were obtained before distraction T1 and after completing active distraction T2. After a three month follow up period a final lateral cephalometric record was evaluated T3. Results: The maxilla was significantly advanced as indicated by the increase in maxillary depth angle and effective maxillary length (median difference, 10 mm). The palatal plane angle showed a significant increase (median difference, 5o), showing clockwise rotation. At T3 there was a slight decrease in maxillary depth angle (median difference, 3o). Effective maxillary length decreased significantly at T3 (median difference, 2 mm). The palatal plane angle decreased (median difference, 3o) and almost returned to its original position, showing a counterclockwise rotation. Conclusion: Maxillary advancement using external rigid distractor resulted in clockwise rotation of maxilla with increase in palatal plane angle and slight increase in mandibular plane angle. The amount of maxillary advancement was slightly reduced during follow up and the palatal plane almost returned to its original position. These changes showed good stable clinical results.

Nasomaxillary complex in size, position and orientation in surgically treated and untreated individuals with cleft lip and palate: A cephalometric overview

Background:This cross-sectional retrospective cephalometric study was designed to clarify whether the maxillary deficiency seen in surgically treated individuals with non-syndromic complete unilateral cleft lip and palate (UCLP) is due to inherent growth potential or iatrogenicity.Materials and Methods:72 adult individuals were randomly selected in the age range of 12-20 years, and were divided into two groups. Group I had 47 untreated individuals. Group II consisted of 25 surgically treated individuals. Lateral and frontal cephalograms of the selected individuals were taken and analysed using Nemoceph software.Results:Group II showed a marked reduction in the cranial base angle, maxillary base length, anterior and posterior maxillary positions, palatal plane angle, maxillary width, maxillary height, occlusal plane height, nasal width and nasal height.Conclusion:Surgical intervention does interfere with growth in the facial region. This could be attributed to the scar tissue in lip and palate region, which has a restraining effect on growth in the facial region. These altered functional matrices play a significant role in determining the growth of facial structures.

Initial growth pattern of children with cleft before alveolar bone graft stage according to cleft type

To test the null hypothesis that there is no significant difference in the initial growth pattern among three cleft types before alveolar bone graft (ABG) according to cleft type (unilateral cleft lip and alveolus [UCLA], unilateral cleft lip and palate [UCLP], and cleft palate [CP]). Samples consisted of the UCLA group, the UCLP group, and the CP group. Individuals were treated with the identical surgical technique by the same surgeon and had no history of orthodontic/orthopedic treatment. Lateral cephalograms taken 1 month before ABG were analyzed using 29 variables. One-way analysis of variance (ANOVA) testing and bivariate and logistic regression analyses were performed. An increasing tendency for Class III relationships in the order of UCLA, UCLP, and CP was noted (ANB, AB-to-facial plane angle, AB-to-mandibular plane angle; P < .001, respectively). UCLP and CP groups demonstrated more posterior positioning of the maxilla (SNA, A-to-N-perp; P < .001, respectively) and a hyperdivergent pattern (gonial angle, SN-GoMe angle, FMA; P < .001, respectively) compared with the UCLA group. Because no differences in palatal plane angle and SN-to-occlusal plane angle were noted among the three groups, the hyperdivergent pattern in the UCLP and CP groups might be due to an innate growth pattern and eventual adaptation of the mandible to maxillary growth. UCLP and CP groups showed more Class III relationships (ANB: P < .05, P < .001, respectively) and a more hyperdivergent pattern (FMA: P < .05, P < .01, respectively) than the UCLA group. When the degree of cleft involvement increases from the primary palate to the secondary palate, the predominance of the Class III relationship and the hyperdivergent pattern increases also.

Efeitos do tratamento da Classe II divisão 1 em pacientes dolicofaciais tratados segundo a Terapia Bioprogressiva (AEB cervical e arco base inferior), com ênfase no controle vertical

OBJETIVO: o presente estudo investigou o controle vertical e os efeitos do tratamento ortodôntico em pacientes dolicofaciais, empregando o AEB cervical e o arco base inferior. MÉTODOS: foi realizada a avaliação cefalométrica de 26 pacientes dolicofaciais com Classe II, divisão 1, idade média de 114 meses. O tratamento ortodôntico envolveu a utilização do AEB cervical na arcada superior e arco base na arcada inferior, até a obtenção da chave de oclusão normal dos molares, e finalizado segundo a Terapia Bioprogressiva, com duração média de 56 meses. Foram avaliados os valores de FMA, SN.GoGn, ANB, Fg-S, S-FPm, comprimento maxilar, comprimento mandibular, AFP (altura facial posterior), AFA (altura facial anterior), IAF (índice de altura facial), ângulo do plano oclusal, ângulo do plano palatino, QT (queixo total), LS (lábio superior) e ângulo Z. RESULTADOS: o tratamento promoveu estabilidade dos planos mandibular, oclusal e palatino. Ocorreu a correção anteroposterior das bases apicais, verificada pela redução significativa da grandeza ANB. A maxila apresentou um suave deslocamento anterior,com um suave aumento da dimensão anteroposterior.A mandíbula apresentou melhora de seu posicionamento em relação à base do crânio e sua dimensão anteroposterior aumentou significativamente. As alturas faciais posterior e anterior permaneceram em equilíbrio, não alterando significativamente o IAF. O perfil tegumentar apresentou melhora significativa. CONCLUSÃO: o tratamento realizado promoveu a correção das bases apicais, com controle dos planos horizontais e das alturas faciais, sendo efetivo no controle vertical.

Evaluation of post-surgical relapse in maxillary surgery using resorbable plate

Background This study was carried out to evaluate the vertical and horizontal changes after maxillary surgery using resorbable plates made of an l-lactic acid and d-lactic acid copolymer of PLA (P(L/DL)LA), and to analyze factors of skeletal pattern and surgical movement affecting the post-surgical change. Materials and methods The subjects consisted of 20 patients who underwent bimaxillary surgery using P(L/DL)LA resorbable plate (Inion CPS, Inion Ltd., Tampere, Finland). Lateral cephalograms were taken at 1 month before (T0), 1 month after (T1) and 6 months after surgery (T2). They were divided into two groups, one showing less relapse (LR) and one more relapse (MR) using K-means clustering analysis of post-surgical relapse (T2–T1). In terms of linear and angular variables of maxillary relapse, the two groups were compared with measurements at the pre-surgical stage (T0), the surgical change obtained (T1–T0) and post-surgical relapse (T2–T1) using Mann–Whitney test. Results Because Frankfort horizontal (FH) to anterior nasal spine (ANS) showed the largest variance in post-surgical relapse of the maxilla, it was used for clustering analysis to define the MR and LR groups. Comparison between the MR and LR groups showed that a short preoperative anterior facial height (AFH) was a significant factor in maxillary relapse. The AFH of the MR group was significantly shorter pre-surgically ( p < 0.01) and was significantly increased postoperatively ( p < 0.05) when compared to the LR group. In post-surgical relapse, AFH, FH to A, FH to ANS and the palatal plane angle of the MR group were significantly decreased. Conclusions In the case of a short AFH, P(L/DL)LA resorbable plates may not provide enough vertical stability in the maxillary position due to the muscle force. Facial height might be an important factor when deciding to use P(L/DL)LA resorbable plates for maxillary surgery.