Premature Contact Research Articles

Does the Posterior Bending Osteotomy in Bilateral Sagittal Split Osteotomy Affect the Condyle Position in Asymmetric Patients?

To measure and compare changes in postoperative condylar position following bilateral sagittal split osteotomy in patients with asymmetry treated using a posterior bending osteotomy (PBO) and conventional methods (shaving of premature contacts). Participants were randomized to either the PBO or conventional group. The inclusion criteria were the need for bilateral sagittal split osteotomy or bimaxillary asymmetric surgery (menton deviation >4mm). The primary outcome variable was changes in the condylar position in the axial, coronal, and sagittal planes 6months after surgery, whereas the secondary outcome variable was changes in temporomandibular joint symptoms. Covariates included surgery type, deformity type, age, and sex. Categorical and numerical variables were analyzed using Fisher exact χ2 test and 2-way analysis of covariance. The study sample comprised 42 patients with a mean age of 23.3years; 57.5% were women. The alteration in the coronal condyle angle was 0.8⁰ ± 0.86⁰ in the PBO and 2.72⁰ ± 0.81⁰ in the conventional group. The differences in the condylar position in the coronal plane were not statistically significant (P=.129). The alteration in the axial condyle angle was 2.31⁰ ± 1.74⁰ in the PBO group and 5.65⁰±1.65⁰ in the conventional group. The alteration in the sagittal plane was 0.44⁰ ± 1.52⁰ in PBO and 0.47⁰ ± 1.44⁰ in the conventional group. Alterations in axial (P=.194) and sagittal (P=.976) condylar positions were insignificant. In the conventional group, statistically significant differences were found in the axial (P=.002) and coronal (P=.002) planes, and the condyle turned inward in both planes. There were no statistically significant differences between the groups or within the groups in the sagittal plane (P>0,5). In PBO and conventional groups, joint noise examination revealed positive results in 11 and 6 patients preoperatively and 1 and 2 patients postoperatively, respectively. A statistically significant decrease in joint noise was detected in the PBO group (P=0,04). The maximum mouth opening without pain was 5.95±1.47 in the PBO group and 7.91±1.39 in the conventional group, respectively. The alteration was not statistically significant between the groups but was significant within the groups (P<.001). PBO effectively prevents premature contact between mandibular segments in facial asymmetry.

Are We Correctly Measuring Mandibular Stability After Surgery-First Approach? A Comparative Study Based on Novel 3-Dimensional Measurements.

Using traditional measures to assess mandibular stability after the surgery-first approach (SFA) may produce inaccurate results because unlike the conventional orthodontic-first approach (OFA), the main dental movements occur after surgery in SFA, which produce unavoidable mandibular movements, especially in cases with postsurgical premature dental contact. As these movements are part of the surgical-orthodontic plan, they should not be considered an actual relapse. In this study, to avoid postsurgical dental movement effects, the authors used the relationship between proximal and distal mandibular segments to evaluate stability after SFA. Four easily located points on computerized tomography/cone-beam computerized tomography reconstructed 3-dimensional images were used to calculate 4 measurements between proximal and distal mandibular segments across the osteotomy line in two matched groups of patients (SFA and OFA) at 3 different time points (before, immediately after, and 1 year after the surgery). A high level of skeletal stability was found in the SFA group, with changes 1 year after surgery not exceeding 0.5mm. The SFA was as skeletally stable as OFA, and the mandibular counterclockwise rotation after surgery was related to the planned dental movements and not the instability of the surgery itself. To avoid the illusion of this preplanned relapse, stability should be measured as a relation between proximal and distal mandibular segments, across the osteotomy and fixation line, and not as a relation between maxillary and mandibular landmarks or between the mandible and facial planes as classically described.

Can a Computational Model Predict the Effect of Lesion Location on Cam-type Hip Impingement?

The Warwick consensus defined femoroacetabular impingement syndrome as a motion-related clinical disorder of the hip with a triad of symptoms, clinical signs, and imaging findings representing symptomatic premature contact between the proximal femur and acetabulum. Several factors appear to cause labral and cartilage damage, including joint shape and orientation and patient activities. There is a lack of tools to predict impingement patterns in a patient across activities. Current computational modeling tools either measure pure ROM of the joint or include complexity that reduces reliability and increases time to achieve a solution. The purpose of this study was to examine the efficacy of a low computational cost approach to combining cam-type hip shape and multiple hip motions for predicting impingement. Specifically, we sought to determine (1) the potential to distinguish impingement in individual hip shapes by analyzing the difference between a cam lesion at the anterior femoral neck and one located at the superior femoral neck; (2) sensitivity to three aspects of hip alignment, namely femoral neck-shaft angle, femoral version angle, and pelvic tilt; and (3) the difference in impingement measures between the individual activities in our hip motion dataset. A model of the shape and alignment of a cam-type impinging hip was created and used to describe two locations of a cam lesion on the femoral head-neck junction (superior and anterior) based on joint shape information available in prior studies. Sensitivity to hip alignment was assessed by varying three aspects from a baseline (typical alignment described in prior studies), namely, femoral neck-shaft angle, femoral version, and pelvic tilt. Hip movements were selected from an existing database of 18 volunteers performing 13 activities (10 male, eight female; mean age 44 ± 19 years). A subset was selected to maximize variation in the range of joint angles and maintain a consistent number of people performing each activity, which resulted in nine people per activity, including at least three of each sex. Activities included pivoting during walking, squatting, and golf swing. All selected hip motion cases were applied to each hip shape model. For the first part of the study, the number of motion cases in which impingement was predicted was recorded. Quantitative analyses of the depth of penetration of the cam lesion into the acetabular socket and qualitative observations of impingement location were made for each lesion location (anterior and superior). In the second part of the study, in which we aimed to test the sensitivity of the findings to hip joint orientation, full analysis of both cam lesion locations was repeated for three modified joint orientations. Finally, the results from the first part of the analysis were divided by activity to understand how the composition of the activity dataset affected the results. The two locations of cam lesion generated impingement in a different percentage of motion cases (anterior cam: 56% of motion cases; superior cam: 13% of motion cases) and different areas of impingement in the acetabulum, but there were qualitatively similar penetration depths (anterior cam: 6.8° ± 5.4°; superior cam: 7.9° ± 5.8°). The most substantial effects of changing the joint orientation were a lower femoral version angle for the anterior cam, which increased the percentage of motion cases generating impingement to 67%, and lower neck-shaft angle for the superior cam, which increased the percentage of motion cases generating impingement to 37%. Flexion-dominated activities (for example, squatting) only generated impingement with the anterior cam. The superior cam generated impingement during activities with high internal-external rotation of the joint (for example, the golf swing). This work demonstrated the capability of a simple, rapid computational tool to assess impingement of a specific cam-type hip shape (under 5 minutes for more than 100 motion cases). To our knowledge, this study is the first to do so for a large set of motion cases representing a range of activities affecting the hip, and could be used in planning surgical bone removal. The results of this study imply that patients with femoroacetabular impingement syndrome with cam lesions on the superior femoral head-neck junction may experience impinging during motions that are not strongly represented by current physical diagnostic tests. The use of this tool for surgical planning will require streamlined patient-specific hip shape extraction from imaging, model sensitivity testing, evaluation of the hip activity database, and validation of impingement predictions at an individual patient level.

Finite Element Analysis of Stress Distribution in Root Canals When Using a Variety of Post Systems Instrumented with Different Rotary Systems.

It is very important for clinicians to provide restorative treatments that provide durability for endodontically treated teeth. Trauma, occlusal premature contact, and features of teeth are some of the issues that can cause vertical root fractures (VRFs) in root canal-treated teeth. The aim of this 3-D study was to compare stress distribution on mandibular premolar teeth when using a variety of post designs instrumented with different rotary systems. Six mandibular premolar teeth were instrumented with the following tools: ProTaper Next, WaveOne (WO), Reciproc (R), ReciprocBlue (RB), F6-Skytaper, and TF-Adaptive. Teeth were scanned using cone beam computed tomography (CBCT) and the images were transferred to the Catia V5R25 software. Data were recorded in a stereolithography (STL) format. Four different post systems were used, fabricated from metal, fiber, zirconia, and titanium, respectively. Dentin, gutta, post, core, and crown models were added to the solid model. ANSYS V17.2 finite element analysis (FEA) software was used to determine stress distribution on each assembly. Finite analysis models were created that allowed for the calculation of stress distribution of 250-N loading at a 45° angle and vertical in relation to the roots. The maximum principal stress and von Mises values were higher under oblique loading on the roots. The F6-Skytaper and WO systems showed lower stress than other systems. The TF-Adaptive instrument showed higher stress distribution than the other models. Fiber and titanium posts showed lower stress than others. The F6-Skytaper, R, and RB instruments were found to be most effective in terms of displacement of the crown, resulting in the lowest stress values. Fiber and titanium posts showed better results than other post systems, while root canals instrumented with the F6-Skytaper and WO instruments were less likely to result in root fractures.

Fatigue crack growth behavior of marine steel under variable amplitude loading-combining DIC technique and SEM observation

This paper experimentally studies the fatigue crack growth (FCG) behavior of AH36 grade marine steel under variable amplitude loading. FCG testing is conducted using compact tension specimens. Digital image correlation technique (DIC) is employed to study the evolution of strain distribution and cyclic fatigue characteristics. Fractographic analysis is performed to explore the overload retardation mechanism. Results indicate that the FCG rate varies significantly under overload application, leading to the extension of fatigue life by 1.03, 1.18 and 2.42 times under the overload ratios (OLRs) of 1.5, 2.0 and 2.5. Reasonable evaluation of the fatigue performance depends on the loading history. Extension of the fatigue life for periodic overload (POL) cases is not a simple superposition of that under two single ones, the interaction effect between the adjacent tensile overloads cannot be neglected. Greater plastic dissipated energy corresponds to more severe plastic deformation at larger OLRs and crack lengths. The larger strain accumulation at the crack tip should account for the greater FCG resistance and more evident overload retardation effect. The fresh fracture surface is destroyed at a certain region after overload due to the premature contact of the crack flanks, confirming that overload induced crack closure exists.

Stomatognathic adaptive motor syndrome: A new diagnosis of temporomandibular disorders

Temporomandibular disorders are the most common symptoms and are often a concept that should not be used as a diagnosis. Temporomandibular disorders (TMD) are a group of conditions that cause abnormal, incomplete, or impaired function of the temporomandibular joint. The etiology or pathophysiology is difficult to understand and largely depends on the anatomical location. It is usually found that the clinical condition reflects a mandibular motor problem rather than a joint problem. The purpose of this study is to determine whether stomatognathic adaptive motor syndrome is a new diagnosis for temporomandibular disorders. Premature or insufficient occlusal contact causes the mandible to move to achieve the ideal intercuspal position, also known as

Fixed Prosthodontic Treatment of Patient with Anterior Deep Bite- A case report

The condition of oral cavity greatly influences the patient's dental care and treatment. In prosthodontic treatments, the anatomy and arrangement of the teeth is one of the factors that must be considered in order to be able to plan a treatment design. Deep bite with larger overlap of the maxillary and mandibular incisors make the lateral load borne by the teeth become greater. This can cause damage to the tooth and periodontal tissues, as well as failure of the denture. This article reports on the treatment of edentulous of the tooth 21 with deep bite with convetional brigde PFM. Clinical examination showed that there was an overlap between the upper central incisors and the lower incisors by 5 mm and there was a toothwear defect in the form of attrition on teeth 31 and 41. The patient was planned to have a 3 unit conventional bridge made with porcelain fused to metal with a metal backing design to reduce the thickness of the preparation in palatal area and minimize contact with opposing teeth. At the insertion, the patient's occlusion is checked and evaluated so that there are no premature contacts and occlusal interference during centric and eccentric movements. The patient is satisfied with the results of the treatment. Treatment with fixed partial denture in deepbite must be well designed and planned to achieve successful treatment.

Camouflage Treatment of Skeletal Anterior Open Bite with Tongue Training

The aim of this case report was to present an adult patient who suffered from poor occlusal function and poor aesthetic appearance due to skeletal anterior open bite. After orthodontic treatment, she was satisfied with improvements of mastication and esthetics. A case of 20-year-old female with skeletal Class II jaw relationship, mandible retrognathism and anterior open bite without signs and symptoms of temporomandibular disorder. Intraoral examination showed premature contact over bilateral posterior teeth and the forward resting position of tongue. Our treatment plan was orthodontic camouflage with extraction of all first premolars and tongue training. As forward resting position of tongue was noted, a tongue crib soldered on molar bands was used and the patient was instructed with tongue exercises. Normal overbite and overjet were achieved within four years of treatment. Her profile became more harmony after correction of anterior open bite. Although the stability of occlusion relies on the position of tongue, the current masticatory and facial profile provide a better quality of life. Orthodontic treatment of skeletal anterior open bite should be very careful. Appropriate diagnosis, differentiation of etiology and proper selection of mechanics must be verified before initiating treatment.

Decomposition-resistant carbonitride precipitates in X30CrMoN15-1 high-nitrogen bearing steel deformed by high-pressure torsion

The X30CrMoN15-1 high-nitrogen bearing steel is far more resistant against premature rolling contact fatigue (RCF) failures than the conventional 100Cr6 bearing steel. However, the origins of this steel's resistance against localized severe plastic deformation, which accompanies RCF failure, are still indefinite.In this work, we use multi-scale characterization techniques to investigate the microstructural changes in through-hardened X30CrMoN15-1 steel upon high-pressure torsion (HPT, maximum shear strain, Ƴmax ∼ 14.14). HPT is used to ingress severe plastic deformation in larger bulk samples mimicking the localized severe plastic deformation induced by crack face rubbing in RCF samples just below the sample surface. Upon HPT, the M23(C, N)6 and M2(N, C) carbonitride precipitates in the microstructure remain intact without decomposition, whereas the matrix martensite deforms severely. This is in contrast to pronounced M3C carbide decomposition observed in high-carbon 100Cr6 bearing steels under equivalent ingress of severe plastic deformation. Apart from the cleanliness of the X30CrMoN15-1 steel avoiding crack-initiating inclusions, we conclude that the superior stability of carbonitride precipitates largely contributes to better RCF performance. We show that the carbonitrides exhibit higher hardness (M23(C, N)6 ∼ 22 GPa, M2(N, C) ∼ 20 GPa) and increased thermodynamic stability in comparison to M3C cementite (hardness ∼ 15 GPa). We evaluate the differences in thermodynamic stability through density functional theory (DFT) calculations. Additionally, we discuss the influence of mechanical properties of the surrounding matrix microstructure on precipitate decomposition.

Risk factors for the development of femoroacetabular impingement in physically demanding occupations: a systematic review

Background: Femoroacetabular impingement (FAI) syndrome, or hip impingement, is a musculoskeletal condition affecting the hip joint. It involves motion- or position-related pain originating from an abnormal, premature contact between the femoral head-neck junction (femur) and the acetabular rim (rim around the hip socket). Cumulative and repetitive mechanical overloads at the hip joint appear to contribute to the development of FAI. However, occupational exposures to such loads in potential high-risk occupational groups (e.g., military personnel and athletes) and the relationships between these exposures and the development of FAI remain unclear.

Occlusal Analysis in Natural Dentition: Systematic Review.

This study aimed to evaluate the effectiveness of conventional occlusal analysis in contrast with digital occlusal analysis in natural dentition. Occlusal analysis allows the identification of normal and abnormal occlusal contact points that alter the craniomandibular cervical system. We searched for articles with keywords [[dental occlusion]], [[natural dentition]], [[occlusal adjustment]], [[Immediate Complete Anterior Guidance Development]] [[mastication]], [[bite force]], [[premature contact]], [[occlusal balance]] [[articulating paper]]], [[spray]], [[Occlusal contacts]], and [[bite strength]]. They were considered observational , odds ratio and case control studies. We found 189 items. After evaluating the abstracts and full texts of the articles, 10 papers met the inclusion criteria. It was found that occlusal analysis allows the identification of the relationship between poor occlusion and the sensitivity of the teeth due to occlusal trauma, which is also related to temporomandibular joint pain in dynamic occlusion. The contacts of greater strength were observed in nonfunctional cusps, 48%, without ruling out the functional cusps, 24%. Despite being the universal method of occlusal control to date, the use of joint paper, remains subjective compared to the digital occlusal control device. Posture is considered directly related to occlusal trauma and temporomandibular disorders; without proper occlusal analysis, a clear diagnosis of the patient's joint condition cannot be obtained. Digital occlusal analysis is more objective than traditional occlusal analysis.

Associations among temporomandibular disorder, headache, shoulder pain, craniofacial morphology, and premature contacts in female children and adolescents with malocclusion

ABSTRACT Purpose Orthodontic patients frequently exhibit signs and symptoms of temporomandibular disorder (TMD) in combination with symptoms around the stomatognathic region (i.e. headache). Although maxillofacial morphology and malocclusion have been widely investigated as risk factors for TMD and headache, their relationship remains unclear and functional factors have not been verified. This study investigated associations among TMD, headache, craniofacial morphology, and premature contacts in female children and adolescents with malocclusion. Materials and methods One hundred twenty female children and adolescents (mean age, 11.4 ± 2.5 years) who sought orthodontic treatment were randomly selected from a cohort of orthodontic patients. The patients were divided into three groups (no condition, at least one condition, ≥ 2 conditions: TMD, headache, and/or shoulder pain). Premature contacts were determined using the functional wax bite method; craniofacial morphology was analysed using lateral cephalometric radiographs. The χ2 test, Tukey test, and ordered logistic regression were used for statistical analysis. Results Patients with TMD and headache had a steep mandibular plane angle (odds ratio = 1.11), but there were no significant differences among groups in other craniofacial morphology parameters. Patients with premature contacts had a higher incidence of combined TMD and headache (odds ratio = 7.72). Premature contacts more strongly contributed to pathogenesis than did mandibular plane angle or age. Conclusion TMD and headache are associated with both craniofacial morphology and premature contacts.

Conservative Physiotherapy Treatment of Femoroacetabular Impingement

Abstract The femoro-acetabular impingement (FAI) syndrome is a motion-related disorder of the hip joint with premature contact between the acetabulum and the proximal femur. It is a relatively new clinical entity and no strict treatment protocols and guidelines have been established yet. Furthermore, patients are often misdiagnosed and not properly treated. We report a clinical case of a young adult female patient presenting with a bilateral FAI-CAM type deformity during the last 2 years. An individual progressive global elastic resistant training program was established which involved stimulation to all affected muscle groups using Pilates concept. Hip-specific and functional lower limb strengthening targeted the deep hip external rotators, abductors and flexors in the transverse, frontal, and sagittal planes. Improving the dynamic stability and Core stability was the main aim of the challenging physiotherapy treatment in this case. A good functional result was registered at 6 months follow up. All therapeutic activities were performed in a pain free range of motion which was of paramount importance for achieving excellent patient compliance and successful outcome respectively. The applied treatment strategy demonstrated to be reliable and could be a helpful tool in the armamentarium of contemporary physiotherapy when dealing with the FAI group of patients.

Sequential digital occlusal analysis in patients with skeletal Class III malocclusion with orthognathic surgery: Surgery-first vs orthodontic-first approach

This study compared changes in occlusal characteristics in patients with skeletal Class III malocclusion with surgery-first approach (SFA) and those with orthodontic-first approach (OFA) through digital occlusal analysis. In this prospective study, 90 consecutive subjects were divided into control, OFA, and SFA groups (30 per group). Force discrepancy, occlusal time, tooth contact, center of force, and force-time graph pattern were calculated for all samples using the T-Scan III system. Between-group differences were analyzed using a 1-way analysis of variance and generalized estimating equations. These parameters were calculated at the following time points: preoperatively, 1-month postoperatively (T1), 4-months postoperatively, and 1-year postoperatively (T3). No significant differences were observed in the parameters between the experimental groups. The force discrepancy of the OFA and SFA groups decreased, approaching the value of controls at T3. The occlusal time significantly increased at T1 and progressively decreased at T3. The initial contact and maximum force were most frequently observed on molars, and its maximum force significantly decreased by 5.72% and 7.40% in the OFA and SFA groups at T3, respectively. The number of tooth contact was significantly reduced at T1 and gradually increased at T3. Moreover, after surgery, the force-time graph pattern was normalized, and the center of force tended to be more centric; however, the most frequent trajectory revealed premature contact during closing. No significant difference was found in all parameters between the OFA and SFA groups. Occlusion deteriorated at 1 month postoperatively but gradually improved at 1 year postoperatively, approaching the controls.

Effect of particle morphology on fatigue crack propagation mechanism of TiB2-reinforced steel matrix composites

Fatigue crack growth mechanisms of as-cast and hot-rolled TiB2-reinforced steel matrix composites (SMCs) fabricated by eutectic solidification are systematically investigated through in-situ scanning electron microscopy (SEM) fatigue experiment system. The experiment results show that the as-cast SMC exhibits a relatively superior fatigue crack growth resistance with respect to the hot-rolled SMC. A lower FCGR at the low and intermediate stress intensity factor (ΔK) range in as-cast SMC is found, which is related to the TiB2 particle morphology. Hexagonal and rectangular primary particles have a high Young’s modulus and strong interfacial bonding, which inhibits the advancing of plastic deformation in front of the crack tip. Three-dimensional interconnected eutectic particle phases composed of dendrites can produce a hardening effect at crack tip and restrain the generation of plastic deformation in this morphology region. The stress-strain field in front of the crack tip is changed by the hard TiB2 particles, which leads to the deflection of the crack path. Hence, the tortuous crack path created by facing these particles causes reduction in the effective driving force of the crack tip and slows the FCGR. The net mismatch between the surfaces lead to premature contact and roughness-induced crack closure further reducing the FCGR. In comparison, large number of hot-rolled micro-cracks in the hot-rolled SMC are detrimental to fatigue crack growth resistance through the coalesce mechanism of micro-cracks, thereby accelerating the FCGR.

Evaluation of dental occlusion as an etiological factor in temporomandibular joint disorders

Introduction: Temporomandibular joint disorder (TMD) is a musculoskeletal disorder characterized by pain, limited mouth opening, joint sounds, mandibular deviation, and chewing disability. Premature contacts may lead to TMD. Role of dental occlusion as an etiological factor for TMD is still controversial. Aim of this study is to analyze the relationship between occlusion time and clinical symptoms of TMD using digital occlusion scan and analysis systems. Methodology: This observational study included patients of any gender, between 18-35yrs of age with TMD but otherwise healthy. Patients with periodontal disease, systemic inflammatory conditions, bruxism and tooth wear, patients undergoing treatment for TMD, orthognathic surgery and orthodontic therapy were excluded from the study. Occlusion and disocclusion time were the parameters assessed. The total sample size of this study was 30. Result: There is significant difference between study and test groups in occlusion and disocclusion time during centric occlusion, disocclusion time in protrusion, right and left lateral excursion. Conclusion: Occlusal interferences may affect the TMJ and can cause TMD.

Microstructure-sensitive finite-element analysis of crack-tip opening displacement and crack closure for microstructural short fatigue cracks

In this paper, the effect of the polycrystalline microstructure on crack-tip opening displacement and crack closure is investigated for microstructural short plane strain fatigue cracks using the finite-element method. To this end, cracks are introduced in synthetically generated microstructures and the grain properties are described using a single crystal plasticity model with kinematic hardening. Additionally, finite-element calculations without resolved microstructure and von Mises plasticity with kinematic hardening are performed. Fully-reversed strain-controlled cyclic loadings are considered under large-scale yielding conditions as typical for low-cycle fatigue problems. The crack opening stress and the cyclic crack-tip opening displacement are significantly influenced by the local grain structure. While the stabilized crack opening stresses obtained with the microstructure-based finite-element model are in good accordance with the von Mises plasticity results, the differences in the cyclic crack opening displacement are addressed to the asymmetric plastic strain fields in the plastic wake behind the crack-tip of the microstructure-based model. The asymmetric plastic strain fields result in discontinuous and premature contact of the crack flanks.

Modified Blair Approach for the Treatment of Mandibular Condyle Fractures.

Purpose:The management of fractures of the condyle of the mandible has been a topic of debate and still no consensus exists in the literature about the most appropriate approach. The objective of this study was to evaluate the efficacy and safety of the modified Blair approach for the open reduction and internal fixation of mandibular condyle fractures.Methods:A retrospective study was conducted on 18 patients with 20 mandibular condyle fractures from 2014 to 2020. All patients were treated surgically using the modified Blair approach. Postoperative occlusion status and mouth opening were assessed for treatment outcomes. Also, the rate of complications such as facial nerve paralysis, wound infection, hematoma, salivary fistula, Frey syndrome, and greater auricular nerve paraeesthesia evaluated.Results:Seventeen out of 18 patients (94.4%) achieved their original pretraumatic occlusion after the surgery. One patient (5.5%) had postoperative occlusal interference due to premature dental contact. The maximal postoperative interincisal distance was measured with a range between 33 and 41 mm (mean 37.6 mm). One patient (5.6%) had transient facial nerve palsy. Also, salivary fistula developed in 1 (5.6%) patient in the postoperative period.Conclusion:The results of this study revealed that the modified Blair approach provides satisfactory clinical outcomes with low complication rates and may offer an alternative, safe, and effective method for open reduction and internal fixation of mandibular condyle fracture.

Photoelastic models applied to dental restorations

To improve the understanding of the changes generated by restorative procedures through photoelastic models. Dental reconstruction should be based on principles of occlusion in order not to cause premature contact points during preparation and restoration procedures that can lead to disorders such as occlusal trauma, temporo-mandibullary joint dysfunction, or fractures. This paper presents a didactic method to objectively visualize occlusal loads and their distribution. Photoelastic models of teeth and maxillary segments were made to visualize the effects of dental preparations and restorations, as well as the wear of premature contact points. The direction, intensity and distribution of stresses in the crown and bone support were analyzed by photoelasticity. The technique allows visualization of how the structures are affected from the cavity preparation, the different stresses with diamond or carbide burs, in addition to observing how a premature contact point not only affects the organ that contains it but also the surrounding structures.

Central giant cell granuloma of the mandibular condyle: additional case and literature review

Introduction: Central giant cell granuloma (CGCG) of the jaws is not a common lesion. Only five cases are reported in the mandibular condyle. Observation: A 25 year-old male presented with preauricular swelling and a premature occlusal contact on the molars. The lesion had radiological features of aggressiveness and a high metabolic uptake. Initial biopsy was misleading. The lesion was treated surgically by resection. Discussion: Histologically, CGCG are very similar to other giant cell lesions such as GCT (Giant cell Tumor) or BTH (brown tumor of hyperparathyroidism). The standard treatment is surgical either by curettage or resection. Only 6 cases have been described in the literature, including this one. The diagnosis is difficult, relying on a bundle of clinical, radiological and histological arguments. However, radical surgery should be performed to avoid the tumor recurrence. The genetic mutations associated with CGCG (notably TRPV4 and RAS pathway) may explain why this tumor is mostly found in the dental part of the jaws and only rarely in the mandibular condyle.