Cant Of Occlusal Plane Research Articles

Comparison of the adult three-dimensional craniofacial features of patients with unilateral craniofacial microsomia with and without early mandible distraction

This study was conducted to analyze the long-term facial growth of patients with craniofacial microsomia (CFM) after early mandible distraction osteogenesis (DO), and compared adult three-dimensional (3D) craniofacial features of patients with and without early mandibular DO for Pruzansky grade II deformities. The study included 20 patients: 9 with early mandible DO (the DO group) and 11 without previous treatment (the NDO group). Longitudinal radiographs were measured for growth changes after DO. The 3D craniofacial images were constructed to compare the craniofacial forms between the two groups. The patients with early DO presented 8 to 9mm forward and downward maxillary growth and 4.6mm limited forward and 17.3mm substantial downward mandibular growth. The ramus length ratio (affected/nonaffected) was 90.8% at DO completion and decreased to 69.5% at growth completion during 13 years of follow-up. Both groups showed obvious craniofacial asymmetry, as indicated by occlusal plane canting, chin deviation, transverse and vertical condyle positions, and mandibular contours. Although all the bilateral differences were higher in the NDO group than in the DO group, no statistical differences were found. Early mandible distraction could not alter the inherent facial growth pattern in patients with grade II CFM. Limited changes are derived for definitive facial correction with early DO.

An evaluation of craniofacial growth pattern in North Indian children

ObjectiveThe aim of this study was to assess craniofacial growth pattern in children with generalized decreased skeletal age and compare it with the children having normal skeletal age. Materials and methodsLateral cephalograms and hand wrist radiographs of 40 patients (age group 3–14 years) were taken and skeletal age assessment was done with hand wrist radiographs according to Greulich and Pyle, based on which two groups were made, Group A – Control group (normal skeletal age) and Group B – study group (decreased skeletal age). Group A had a sample size of 21 and Group B, a sample size of 19. These were further divided into subgroups according to age: subgroup (a) – 3 to 6 years, subgroup (b) – 7 to 11 years and subgroup (c) – 12 to 14 years. The skeletal and dental patterns were analyzed with Down's Cephalometric analysis. Student “t” test was used to verify comparisons in all the subgroups of patients of Group A and Group B. ResultsThe facial angle and Cant of occlusal plane exhibited maximum difference between the two groups which indicated that mandibular growth was affected more than other bones in diseased child patients. ConclusionThe present study led to the conclusion that craniofacial growth was retarded in children with generalized decreased skeletal age in comparison to healthy child patients.

Cephalometric study of the position of ala-tragus line in relation to Frankfort horizontal plane and occlusal plane among Ludhiana population

Introduction: The inclination of occlusal plane (OP) is determined by paralleling the OP to ala-tragus line. Inspite of its wide acceptability, the exact location of tragal point on ala-tragus line is unclear. In addition, morphologic features vary among various ethnic groups. Therefore, it is important to evaluate the exact reference point on tragus among Ludhiana population. Aim: The aim of this study is to determine the posterior reference point of the ala-tragus line that forms the most parallel line with the natural OP among Ludhiana population. Methodology: Digital lateral cephalograms were taken in 100 dentulous Angle's Class I subjects of 18–30 age group. Stainless steel balls were attached to ala of the nose (A) and three points that corresponded to superior (S), middle (M), and inferior (I) points on the tragus of ear. The angle formed by each line (SA, MA, and IA planes) with Frankfort horizontal (FH) plane and OP were measured on all tracings of cephalograms. Results: The mean angular value of IFH (angle between IA-FH planes) was the closest to the Cant of OP, and the mean angular value of IOP (angle between IA plane and OP plane) was the least compared to angles MOP (angle between MA-OP planes) and SOP (angle between SA-OP planes). Conclusion: The inferior point marked on tragus is the most appropriate point for marking ala-tragus line among Angle's Class I subjects of Ludhiana.

Smile aesthetics: The impact of occlusal plane cant along with gingival display on smile attractiveness.

Inverse relationship between occlusal cant and gingival display.

Full mouth rehabilitation utilizing implant-assisted removable partial denture with a canted occlusal plane: a case report

Full mouth rehabilitation utilizing implant-assisted removable partial denture with a canted occlusal plane: a case report

Class II malocclusion with accentuated occlusal plane inclination corrected with miniplate: a case report.

ABSTRACTIntroduction: A canted occlusal plane presents an unesthetic element of the smile. The correction of this asymmetry has been typically considered difficult by orthodontists, as it requires complex mechanics and may sometimes even require orthognathic surgery. Objective: This paper outlines the case of a 29-year-old woman with Class II malocclusion, pronounced midline deviation and accentuated occlusal plane inclination caused by mandibular deciduous molar ankylosis. Methods: The patient was treated with a miniplate used to provide anchorage in order to intrude maxillary teeth and extrude mandibular teeth on one side, thus eliminating asymmetry. Class II was corrected on the left side by means of distalization, anchored in the miniplate as well. On the right side, maxillary first premolar was extracted and molar relationship was kept in Class II, while canines were moved to Class I relationship. The patient received implant-prosthetic rehabilitation for maxillary left lateral incisor and mandibular left second premolar. Results: At the end of treatment, Class II was corrected, midlines were matched and the canted occlusal plane was totally corrected, thereby improving smile function and esthetics.

The impact of occlusal plane cant along with gingival display on smile attractiveness.

To evaluate the influence of occlusal plane cant in conjunction with maxillary gingival display on perception of smile attractiveness by orthodontists, dentists, and laypersons. Faculty of Dentistry at Baskent University. A total of 204 raters for smile attractiveness. A frontal intra-oral photograph of aligned teeth was modified using image processing software. Six different occlusal lines representing 0° to 5° cants were obtained by tilting the photographs. Each occlusal cant was adjusted in five manners resulting in five different gingival display amounts. Attractiveness of the 30 different smiles was evaluated by 204 raters divided into three groups (n = 68 in each group). Both occlusal cant (p < 0.001) and gingival display amount (p < 0.001) had a statistically significant influence on smile attractiveness. Smile attractiveness scores with reference to amount of gingival display showed a significant difference between rater groups (p < 0.001). Orthodontists preferred 1-mm coverage of upper central incisors by the upper lip, whereas dentists and laypersons preferred 2 mm. Significant (p < 0.001) interaction was observed between occlusal cant and gingival display amount, which influenced smile attractiveness. Increase in both occlusal plane cant and gingival display negatively influences smile attractiveness. The influence of occlusal plane cant becomes less when gingival display increases, whereas the influence of gingival display decreases when occlusal cant increases. Dentists are more generous than orthodontists, while laypersons are the most generous regarding smile attractiveness scores.

Quantification of dental prostheses on cone-beam CT images by the Taguchi method.

The gray values accuracy of dental cone‐beam computed tomography (CBCT) is affected by dental metal prostheses. The distortion of dental CBCT gray values could lead to inaccuracies of orthodontic and implant treatment. The aim of this study was to quantify the effect of scanning parameters and dental metal prostheses on the accuracy of dental cone‐beam computed tomography (CBCT) gray values using the Taguchi method. Eight dental model casts of an upper jaw including prostheses, and a ninth prosthesis‐free dental model cast, were scanned by two dental CBCT devices. The mean gray value of the selected circular regions of interest (ROIs) were measured using dental CBCT images of eight dental model casts and were compared with those measured from CBCT images of the prosthesis‐free dental model cast. For each image set, four consecutive slices of gingiva were selected. The seven factors (CBCTs, occlusal plane canting, implant connection, prosthesis position, coping material, coping thickness, and types of dental restoration) were used to evaluate scanning parameter and dental prostheses effects. Statistical methods of signal to noise ratio (S/N) and analysis of variance (ANOVA) with 95% confidence were applied to quantify the effects of scanning parameters and dental prostheses on dental CBCT gray values accuracy. For ROIs surrounding dental prostheses, the accuracy of CBCT gray values were affected primarily by implant connection (42%), followed by type of restoration (29%), prostheses position (19%), coping material (4%), and coping thickness (4%). For a single crown prosthesis (without support of implants) placed in dental model casts, gray value differences for ROIs 1–9 were below 12% and gray value differences for ROIs 13–18 away from prostheses were below 10%. We found the gray value differences set to be between 7% and 8% for regions next to a single implant‐supported titanium prosthesis, and between 46% and 59% for regions between double implant‐supported, nickel‐chromium alloys (Ni‐Cr) prostheses. Quantification of the effect of prostheses and scanning parameters on dental CBCT gray values was assessed.PACS numbers: 87.59.bd, 87.57Q

Esthetic evaluation of dental and gingival asymmetries.

The aim of this study was to determine which smile asymmetries were less esthetic, dental or gingival. Laypeople (297), generalists (223), prosthodontists (50) and orthodontists (49), evaluated the esthetics of digitally-modified images taken from the same frontal intra-oral photograph, using the same lips, simulating upper maxillary midline shift, occlusal plane inclination, asymmetric incisal edge and asymmetric gingival migration. The images were later paired into 3 groups. The only ones considered esthetic were the asymmetric incisal edge of the 0.5 mm shorter upper central incisor and the asymmetric gingival migration (2 mm) of the upper central incisor. In the paired images, upper maxillary midline shift vs. occlusal plane inclination, the former was rated less esthetic, while in the asymmetric incisal edge vs. asymmetric gingival migration pair, the latter was considered to be less esthetic. Laypeople and generalists consider smiles more attractive. The only images considered esthetic were the asymmetric incisal edge of the central incisor shorter by 0.5 mm and the 2 mm asymmetric gingival migration of the upper central incisor. In the horizontal plane (maxillary midline shift vs. occlusal plane cant), the dental asymmetries were considered less esthetic than the gingival asymmetries. However, in the vertical plane (asymmetric incisal edge vs. asymmetric gingival migration) the opposite was recorded.

Esthetic mounting (OP1)을 사용하여 교합면 재구성을 시행한 증례

붕괴된 교합평면을 보철적으로 재구성하는 과정에 있어 face-bow와 교합기는 필수적으로 필요한 기구로 사용되어왔다. 일반적으로 Ear rod를 사용하는 face bow는 상악 정중선의 오차와 교합평면의 canting이 발생할 가능성이 있는데 이런 문제점을 해결하기위해 환자의 안면 정중선을 기준으로 하는 face bow가 개발되어왔다. Ear-bow를 이용한 mounting에서 종종 발생하는 오류를 보완하는 방법으로 환자 안면의 중심과 교합기의 중심을 일치시키려는 개념의 mounting technique이 시도되고 있으며 이를 esthetic mounting이라 한다. 이들 중 하나인OP finder 1(OP1)을 사용한 증례를 보고하고자 한다. A face-bow and an articulator have been used as crucial devices in a prosthodontic reconstruction of a collapsed occlusal plane. In order to avoid inaccuracy of median line in maxilla and the canted occlusal plane both of which may result from using a facebow with ear rods, a facebow that locate a patient's facial median line as reference line has been under development. A mounting technique that tries to bring a center of patient's face into line with the center of the articulator, called esthetic mounting, is currently employed to overcome the imprecision resulted from mounting with ear-bow transfer. We would like to study a case that used OP finder 1, one of the esthetic mounting techniques.

Use of the Matching Optimal Symmetry Plane Method in Planning Surgical Correction of Facial Asymmetry—A Preliminary Report of 20 Patients

A voxel-based median plane (optimal symmetry plane [OSP]) was developed to assess facial bone asymmetry. The purpose of the present study was to introduce a new method of planning surgical correction of facial asymmetry using the OSPs as guides and test its effectiveness. A retrospective study was conducted of 20 facial asymmetry patients with a mandibular deviation of 4 mm or greater or 4° or more that required surgical correction. In the test group (n = 8), the plans for asymmetry correction were formulated using the matching OSP method, in which the OSPs of the facial bones are tracked and matched during the model surgery setup. In the control group (n = 12), traditional planning was conducted. The traditional plans were cross-checked for symmetry through tracking and revised as needed. The symmetry results of the plans were compared between the 2 groups and within the control group. The outcome measures were the deviation distances between the OSPs of the midface and mandible at the anterior or posterior mandible, the occlusal plane cant, and the angle formed by the 2 OSPs. Surgery was performed in accordance with the final plans, and the results were assessed for symmetry. The traditional plans left a major mandibular deviation in 5 of the 12 control subjects compared with none in the test group. The test group did significantly better than the control group. The revised plans were significantly better than the initial plans. Postoperatively, significant improvements in symmetry were observed. The new method resulted in surgical plans that brought about significantly less postoperative mandibular deviation while maintaining a reasonable occlusion.

Management of occlusal canting with miniscrews

A 14-year-old boy with a skeletal Class II malocclusion and open bite whose chief complaint was a posterior crossbite showed a canted occlusal plane with asymmetric gummy smile and mandibular deviation at clinical examination. The treatment with miniscrews focused on the bilateral intrusion of the maxillary posterior teeth and, after resolving the open bite, a new biomechanical technique involving joined miniscrews was applied for an en masse intrusion of the left side. This treatment strategy achieved optimal occlusion with improvements to the sagittal, vertical, and transverse relationships and achieved a harmonious smile.

Occlusal plane canting reduction accompanies mandibular counterclockwise rotation in camouflaging treatment of hyperdivergent skeletal Class II malocclusion

To investigate the occlusal configurations of the hyperdivergent skeletal Class II malocclusion and their alterations during the camouflaging treatment in an attempt to identify occlusal changes that might be related to mandibular counterclockwise rotation. Cephalograms of 126 subjects with hyperdivergent skeletal Class II malocclusion and 126 subjects with a clinically normal skeletal pattern were chosen. Several measurements were calculated and compared between the groups. To examine the effects of treatment, two groups were established according to mandibular rotation: counterclockwise rotation (CCR) and the opposite clockwise rotation (CR). After 40 subjects were excluded, the other 86 Class II subjects were assigned to CCR (n = 22) and CR (n = 64). Their pretreatment (T1), posttreatment (T2), and postretention (T3) cephalograms were obtained. Measurement changes (T3-T1) were analyzed in each group and compared between groups. Compared with the normal skeletal pattern, the cant of the occlusal plane (OP) of the study subjects was significantly steeper and the vertical heights of the incisors were significantly larger for the malocclusion. Compared with the changes in CR, there was a prominent reduction of the OP canting with remarkable intrusion of the maxillary incisor in CCR. Increased OP canting with overerupted incisors is evident in the hyperdivergent skeletal Class II malocclusion. During the camouflaging treatment, reduction of OP canting could occur. It was accompanied by mandibular counterclockwise rotation and intrusion of the maxillary incisor.

Uncovering and treating asymmetry before 6years in our daily clinical practice: Option or obligation? Orthodontics or orthopedics?

Skeletal asymmetry of the TMJ or maxillary arch is always associated with basicranium skeletal asymmetry and can become pathogenic for the development of masticatory function. What means do we dispose of in our everyday practice for early screening and treatment of these often little-known asymmetries? This is the focus of our article, which draws on over 10years' experience within our own practices. We have systematically applied the following ground-rules: (a) look for clinical signs of facial asymmetry well before eruption of the deciduous teeth, and when the deciduous teeth have erupted; (b) during extraoral examinations, apply a new diagnostic tool involving a tracing of the soft tissue axes of the ears in order to uncover patients at high risk of intertemporal asymmetry; (c) look for maxillary intra-arch asymmetry using an Orthogrille(®)-type measurement grid; (d) look for inter-arch asymmetries using the "cranial" laterality test. Then, still during the deciduous dentition phase, we initiate treatment. In this paper, we outline the use of symmetrization sectorial screws combined with unlocking sliding plates in order to correct intra-arch and inter-arch asymmetry. We conclude by outlining techniques to remedy canted occlusal plane using a modified Fränkel-type appliance.

Canting of the occlusal plane: Perceptions of dental professionals and laypersons

Objectives: To determine if canting of the occlusal plane influences esthetic evaluation of the smile among orthodontists, dentists and laypersons. Study Design: A frontal photo of a smile with 0º occlusal plane canting in relation to the bipupillary plane was modified using Adobe Photoshop C3 (Adobe Systems Inc, San José, California) to generate two images with occlusal plane inclinations of 2º and 4º. The three images were evaluated esthetically by orthodontists (n=40) general dentists (n=40) and laypersons (n=40). Each image was awarded a score as follows: 1=esthetically acceptable; 2=moderately acceptable; 3=esthetically unacceptable. Evaluators also placed the three images in order in preference. Data were analyzed using the Kruskal-Wallis (p<0.05) and the Mann-Whitney tests, applying the Bonferroni Correction (p<0.016). Results: No significant differences (p> 0.05) were found between the three groups for 0º and 2º cants (median for orthodontists=1; general dentists=1; laypersons=1). Orthodontists (median score=3) made evaluations of the image with 4º occlusal plane that were significantly different from general dentists (median=2) and laypersons (median=2). All three groups put the 0º image in first place in order of esthetic acceptability, the 2º image in second place and the 4º image in third place. Orthodontists placed the 0º image in first place with significantly greater frequency (p<0.016) than laypersons. Conclusions: Occlusal plane canting of 0º and 2º were evaluated as esthetically acceptable by the three groups. The 4º occlusal plane cant was evaluated more negatively by orthodontists than by general dentists and laypersons. All three groups placed the 0º image in first place of esthetic acceptability, 2º in second place and 4º in third. Orthodontists put the 0º image in first place with significantly greater frequency than laypersons. Key words:Canting, perception, smile, orthodontics, dental esthetics.

Cephalometrically assessing the validity of superior, middle and inferior tragus points on ala-tragus line while establishing the occlusal plane in edentulous patient

PURPOSEThe purpose of this study was to decide the most appropriate point on tragus to be used as a reference point at time of marking ala tragus line while establishing occlusal plane.MATERIALS AND METHODSThe data was collected in two groups of subjects: 1) Dentulous 2) Edentulous group having sample size of 30 for each group with equal gender distribution (15 males, 15 females each). Downs analysis was used for base value. Lateral cephalographs were taken for all selected subjects. Three points were marked on tragus as Superior (S), Middle (M), and Inferior (I) and were joined with ala (A) of the nose to form ala-tragus lines. The angle formed by each line (SA plane, MA plane, IA plane) with Frankfort Horizontal (FH) plane was measured by using custom made device and modified protractor in all dentulous and edentulous subjects. Also, in dentulous subjects angle between Frankfort Horizontal plane and natural occlusal plane was measured. The measurements obtained were subjected to the following statistical tests; descriptive analysis, Student's unpaired t-test and Pearson's correlation coefficient.RESULTSThe results demonstrated, the mean angle COO (cant of occlusal plane) as 9.76°, inferior point on tragus had given the mean angular value of IFH [Angle between IA plane (plane formed by joining inferior point-I on tragus and ala of nose- A) and FH plane) as 10.40° and 10.56° in dentulous and edentulous subjects respectively which was the closest value to the angle COO and was comparable with the values of angle COO value in Downs analysis. Angulations of ala-tragus line marked from inferior point with occlusal plane in dentulous subject had given the smallest value 2.46° which showed that this ala-tragus line was nearly parallel to occlusal plane.CONCLUSIONThe inferior point marked on tragus is the most appropriate point for marking ala-tragus line.

Association between craniofacial asymmetry and unilateral temporomandibular joint sounds in adult patients using 3D‐computed tomography

The purpose of this study was to investigate the possible relationship between unilateral temporomandibular joint (TMJ) sounds and craniofacial asymmetry, using 3D-computed tomography (CT) measurements. Forty-one reconstructed 3D-CT models of adult subjects were measured to analyze craniofacial asymmetry. Subjects were divided into two groups depending on the presence (n = 20) or absence (n = 21) of unilateral joint sounds, and the results compared using the Mann-Whitney U-test. To investigate the association between these parameters, the Pearson correlation coefficient was calculated. Asymmetries in the maxillary and mandibular structures were statistically significant (P < 0.05) for subjects with unilateral TMJ sounds and for controls, except in the case of maxillary rotation and mandibular ramus height (P > 0.05). The highest deviations found were frontal and lateral ramal inclination, goniac angle and canting of occlusal plane. Adult patients with unilateral joint sounds may have skeletal jaw asymmetry and a canted occlusal plane.

New Approach for the Surgico-Orthodontic Treatment of Hemifacial Microsomia

One of the important clinical findings in hemifacial microsomia (HFM) is facial asymmetry (FA) with unilateral underdevelopment and malformation of the mandible and/or maxilla. Unilateral distraction osteogenesis (UDOG) of the mandible has been used for correction of FA in HFM patients. However, return to the original FA status often occurs because of contraction of the distracted bony segment of the mandible and insufficient compensatory downward growth and skeletal midline correction of the maxilla on the affected side. Although bimaxillary UDOG procedure in the maxilla with Le Fort I osteotomy and the mandible with ramus osteotomy was suggested as an alternative treatment modality, it has some disadvantages including elongation of the face, inaccuracy of vector control, and less predictable results. Occlusal plane canting, skeletal midline deviation of the maxilla, and unilateral mandibular hypoplasia might be simultaneously corrected by fixation of the maxilla into a proper position after Le Fort I osteotomy and UDOG of the mandible. Three-dimensional virtual simulation using three-dimensional computed tomography data could help to accurately predict surgical outcomes. In addition, transarch elastic traction from the orthodontic mini-implants on the unaffected side of the mandible to the maxillary posterior teeth on the affected side can produce a plastic molding of the regenerated bone in the distraction area of the mandible and induce compensatory dentoalveolar downward development of the maxillary posterior teeth. Therefore, the purpose of this article was to introduce a new approach for the surgico-orthodontic treatment consisting of simultaneous maxillary fixation and unilateral mandibular distraction with transarch elastic traction in HFM patients.

Use of rhythmic wire system with miniscrews to correct occlusal-plane canting

Occlusal-plane canting is a challenging problem for orthodontists because it cannot be solved easily without surgical intervention. Normally, a LeFort I osteotomy and concomitant mandibular surgery is used to correct the problem, even in patients with mild facial asymmetry but with noticeable occlusal-plane canting. Skeletal anchorage can be used in patients with occlusal canting to reduce the need for orthognathic surgery. The purpose of this article was to introduce a biomechanical system-rhythmic wire- to correct occlusal-plane canting. The records of 2 patients treated with this system are shown.

Simultaneous Correction of Hard- and Soft-Tissue Facial Asymmetry

The purpose of this study was to evaluate outcomes of simultaneous correction of the hard- and soft-tissue facial asymmetry with face lift procedure using a resorbable fixation device (Endotine Ribbon; Coapt Systems, Palo Alto, CA) during bimaxillary orthognathic surgery in cases with severe facial asymmetry. The samples consisted of 8 patients (mean age, 23.3 [SD, 4.4] years; 8 skeletal class III and 2 class II malocclusion) who received bimaxillary orthognathic surgery and a face lift procedure using a resorbable fixation device. Preoperative cephalometric evaluation of the maxillary occlusal plane cant and chin point deviation and data on surgical movement, site, time, and difficulty of face lift procedure were collected at 1 week before operation and during operation procedure. The amounts of lip cant between preoperation and postoperation were compared. Pain, stability of fixation, adverse effects, relapse, and patients' and surgeon's satisfaction were evaluated at 6 months after operation. Initial and final amounts of the lip cant were 4.15 (SD, 0.53) and 0.80 (SD, 0.48) mm (correction rate, 76.8%). The face lift procedure took 28.4 (SD, 3.3) minutes without difficulty. There were no severe complications such as hematoma, facial nerve injury, and postoperative scar. By the patients' and surgeon's view, all had satisfactory jowl elevation, lip canting correction, and achievement of the soft-tissue symmetry without evidence of recurrent asymmetry or loss of fixation. If the face lift procedure using a resorbable fixation device is done with proper vector control during orthognathic surgery, the hard- and soft-tissue facial asymmetry can be corrected simultaneously with satisfactory outcomes.