Protrusive Movements Research Articles

Arthrocentesis Versus Level 1 Arthroscopy in Internal Derangement of Temporomandibular Joint.

Internal derangement of the temporomandibular joint is defined as an abnormal position of the articular disc in relation with mandibular condyle and articular eminence presenting as disc displacement with or without reduction. This study was conducted on thirty patients diagnosed with Internal derangement of TMJ consisting of 8 males and 22 females averaging 34.6years. Two groups Conventional Arthrocentesis (Group A) and Level 1 Arthroscopy (Group B) consisted of 15 cases each divided alternately. Clinical evaluation parameters included VAS for pain, maximal interincisal opening, deviation on mouth opening, range of motion including lateral excursion & protrusion movements recorded at 1week, 1month & 6months postoperatively. Wilke's Staging according to MRI findings was recorded preoperatively and 6months postoperatively. At 6month follow-up, average reduction in VAS for pain & deviation on mouth opening was 72.43% & 24.73% in Group A and 77.66% & 65.41% in Group B, respectively. Average increase in MIO, right & left excursion & protrusion movements was 29.55%, 31.33%, 20.12% & 32.45% in Group A and 34.94%, 41.37%, 39.29% and 36.51% in Group B, respectively. Improved results were obtained clinically for all Wilke's stages in both groups with more number of patients improving in Group B. On comparing results, improvement was observed in various clinical evaluation parameters of both the groups at 6months follow-up. However, statistically significant & better results were obtained for the Arthroscopy group.

Computerized occlusal analysis of two different removable retainers used during retention phase- A Randomized controlled trial

ABSTRACT Aim: To evaluate and compare occlusal contact force distribution, occlusion time and disclusion time following wear of Begg’s wrap around retainer and Vacuum formed retainer after completion of orthodontic treatment using a T-scan III. Materials and Methods: Twenty subjects after completion of active orthodontic treatment were randomly allocated into two groups, Group I – Begg’s wrap-around retainer (n-10) and Group II–vacuum formed retainer (n-10) one patient was lost to follow up in each group and the final sample size assessed at T1 in each group was 9. T-scan III was used at two-time intervals, T0 – first scan taken immediately after debonding and T1 – taken during retention any time between 10 and 12 months. Comparison of parameters within the groups was done using paired t-test and comparison between the groups was done using independent t-test. Results: No statistically significant difference in the distribution of occlusal contact forces was noted in both groups at T0 and T1 (p value<0.05). Disclusion time reduced in both groups at T1 but a statistically significant reduction in the disclusion time of left lateral excursive movement and protrusive movements (p value<0.05) was noted (T0-T1) in Group I. Statistically significant increase in the occlusion time was noted in Group II (T0-T1) at T1 between the two groups. Conclusion: No differences in occlusal contact force distribution was noted within and between the two groups. Disclusion time reduced in subjects on Begg’s wrap around retainers indicating favourable muscle activity and Occlusion time increased in subjects on vacuum formed retainers.

Effects of energy density attenuation on the stability of keyhole and molten pool during deep penetration laser welding process: A combined numerical and experimental study

The energy density attenuation of focused laser beam could induce inconsistent thermodynamic behaviors from near field to far field, which leads to the deterioration of the welding stability. However, the influence of energy density attenuation on welding process remains unclear. In this work, a set of innovative characterizing methods are presented to quantitatively evaluate the features of the front keyhole wall and molten pool dynamics. The energy density attenuation and correlative phenomena are numerically studied using a multiphase model. This model incorporates an improved ray-tracing method which can describe the actual beam profile more accurately. Based on experimental and numerical results, a unique melting behavior, i.e., the alternate melting between keyhole wall and keyhole bottom due to the energy density attenuation, is discovered. This melting behavior is primarily caused by movement of protrusions along the front keyhole wall, which can change the energy absorption efficiency significantly. Besides, it is found that the fluctuation amplitude of molten pool is closely related to this melting behavior. By sustaining protrusion movement process, the melting behavior can be regulated and hence improve the molten pool stability. Finally, an optimization method by adjusting the beam defocus and inclination is proposed and testified to improve the welding stability.

INFLUÊNCIA DA TÉCNICA DE PREPARO SOBRE O CONTORNO CERVICAL DOS LAMINADOS CERÂMICOS: RELATO DE CASO

Introdução: Devido à crescente demanda estética, a odontologia restauradora se renova na intenção de alcançar melhores resultados na harmonia do sorriso. Entretanto, a atenção deve voltar-se também aos tecidos periodontais, visto que há uma integração entre material restaurador e os tecidos. Objetivo: Descrever e discutir as etapas clínicas para a confecção de laminados cerâmicos, atentando-se a preparos minimamente invasivos, contorno cervical e fatores que podem intervir na longevidade do procedimento. Relato de caso: Paciente do sexo masculino, 28 anos de idade, compareceu a Associação Brasileira de Odontologia – ABO, seção de Alagoas, relatando insatisfação em relação ao tamanho dos seus dentes. Os arcos superior e inferior foram moldados para a obtenção dos modelos de estudo e enceramento diagnóstico. Ao início do tratamento foi orientado ao paciente clareamento dental pela técnica combinada. O preparo dos dentes foi guiado por uma matriz de silicone, sendo estes uniformes e conservadores, seguido de moldagem, fase laboratorial e cimentação final. Finalizado o caso foi realizado o ajuste oclusal solicitando ao paciente que realizasse movimentos de lateralidade e protrusão. Conclusões: A técnica do preparo influência na longevidade dos laminados cerâmicos, por relacioanar-se à adesão e a saúde periodontal. O preparo deve ser mínino e limitado ao esmalte dental sempre que possível, determinando assim um maior e melhor prognóstico.

Management of Internal Derangement of Temporomandibular Joint Disc Displacement with Reduction Using Two Different Lines of Treatment

Objetive: This study was to compare the effectiveness of arthrocentesis versus the insertion of anterior repositioning splint (ARS) in improving the mandibular range of motion (MRM) for patients with the temporomandibular joint (TMJ) anterior disc displacement with reduction (ADDwR). Methods: 36 patients diagnosed as ADDwR were recruited and divided randomly into two groups. The first group (G1) was treated by arthrocentesis, and the second (G2) was treated using ARS. All patients were reexamined after six months. Results: Except that for protrusive movement, there were significant differences between the two groups for the percentage changes of the MRM as measured by the amount of pain free opening, unassisted opening, maximum assisted opening, right lateral and left lateral movements (p &lt; 0.05). Conclusion: Within the context of the current study, the non-invasive, lower cost ARS, provided better results in improving the MRM when managing ADDwR cases. Keywords Arthrocentesis; Anterior repositioning splint; TMD; Internal derangement; Anterior disc displacement; Mandibular range of motion.

Temporomandibular Joint Prostheses: Optimal Materials for the Optimal Stomatognathic System Performance-Preliminary Study.

The aim of this study was to quantitatively evaluate alloplastic Temporomandibular Joint (TMJ) Prostheses against other treatment modalities regarding the jaw kinematics. Six patients with Temporomandibular Joint Prostheses, four with mandibular ramus Patient-Specific Implant (PSI) with condylar head preservation, and four after mandibular condylectomy were evaluated by the means of axiography (Cadiax Compact 2), which is the noninvasive three-dimensional study of condylar movements. The patients were also evaluated clinically for the mandibular movements. The study revealed that the significant movement limitations occurred bilaterally in patients fitted with TMJ prosthesis. For the protrusion movement, the vector length of the movement (L) for the TMJ prosthesis was 0.31 vs. 3.01 mm for the PSI (Kruskal–Wallis chi-squared = 9.1667, df = 2, p-value = 0.01022, post hoc Dunn p-value = 0.015) and for the laterotrusion to the operated side, the length of the vector (L) was 0.66 vs. 3.35 mm, respectively. Statistically significant differences between groups were most frequent for the laterotrusion to the unoperated side. The study shows that a further development on TMJ Prostheses geometry and materials is needed.

Mandibular orthognathic surgery does not alter temporomandibular joint symptoms – A single centre prospective study

AbstractAimMandibular orthognathic surgery has been considered a risk factor for developing temporomandibular dysfunction (TMD). A prospective follow‐up study was initiated to examine the correlation between two surgical techniques for mandibular advancement and setback on mandibular range of movement and temporomandibular joint symptoms.Materials and methodsThirty‐four patients who underwent mandibular orthognathic surgery were included. Twenty patients were operated with the intraoral vertical ramus osteotomy (IVRO) technique and subsequent rigid maxillomandibular fixation (MMF) for 6 weeks; 14 were operated with the bilateral sagittal split osteotomy (BSSO) with internal osteosynthesis. The patients completed a questionnaire regarding subjective symptoms and were examined 1 day before, and 1 year after surgery. Evaluations of tenderness upon muscular and articular palpation, assessment of mandibular mobility and calculation of the Helkimo index were performed.ResultsMean maximum mouth opening was reduced one year after surgery for both experimental groups. The BSSO‐group also experienced reduced laterotrusive and protrusive movements. No statistically significant differences within or between the groups were found for the Helkimo clinical dysfunction score. Both groups reported no differences in TMD‐related symptoms before and after surgery, and no differences were found between the groups.ConclusionsMaximum mandibular movement was slightly reduced for both surgical techniques. Assisted mouth opening, laterotrusive and protrusive mandibular movements were reduced after BSSO, and maximum mouth opening was reduced after IVRO. However, the differences were small and both groups were well within the normal range. None of the groups experienced changes in TMD‐related symptoms.

Functional properties of single motor units in the human medial pterygoid muscle: Thresholds.

Little is known regarding the functional properties of single motor units (SMUs) in the medial pterygoid muscle (MPt) during jaw movements. The aims are (a) to report the thresholds of onset of MPt SMUs during 4 goal-directed jaw movement tasks, and (b) to determine whether the threshold of onset of SMU activation varies with the velocity of jaw movement and the location within the muscle. Intra-muscular electrodes were inserted in the right MPt of 18 participants performing ipsilateral (right), contralateral, protrusive and opening-closing jaw movements recorded at 2 velocities. Task phases were as follows: BEFORE, OUT, HOLDING, RETURN and AFTER. SMU onset thresholds were determined from the displacement (mm) of the lower mid-incisor point. Electrode location within 4 arbitrary muscle divisions was determined with computer tomography. Statistical tests: Spearman's correlations, Kruskal-Wallis tests; significance accepted at P<.05. A significant inverse relation occurred between velocity and threshold for the RETURN of the ipsilateral movement (n=62 SMU thresholds), while a significant positive relation occurred for the OUT of the contralateral movement (n=208); there were no significant associations for the protrusive (n=131) and opening-closing (n=58) tasks. Significant threshold differences occurred across the 4 muscle divisions only during the OUT of the contralateral and protrusive movements. Some evidence was provided for gender differences in MPt SMU properties. The absence of a significant inverse relation between velocity and SMU threshold for most recorded movements suggests the MPt acts as a stabilizer of the jaw in horizontal and opening-closing jaw movements.

Does Dynamic Intermaxillary Fixation With Elastics Improve Outcomes Following Unilateral Condylar Fracture?

The use of rigid versus semi-rigid intermaxillary fixation (IMF) following subcondylar fractures is controversial. This study aims to investigate whether the "dynamic" elastic fixation technique improves the outcomes, compared to the rigid fixation technique for the treatment of displaced subcondylar fractures in adults. This nonblinded randomized clinical trial was performed on adult patients with unilateral displaced mandibular subcondylar fractures. Patients were randomly allocated into two groups (n=17). The primary predictor variable was wire versus elastic IMF. Changes in primary (mouth opening) and secondary (other clinical and radiological) outcomes were recorded. Data were analyzed with the t test and Mann-Whitney test with SPSS software version 20. P-value < .05 considered as significant. In this study 34 patients (with mean age of 33.03±1.79, 23.5% females & 76.5% males) in two groups (Elastics & Wire) followed up to 6months. The Elastics group showed significant improvement in mouth opening (primary outcome) after 1 month of follow-up, but the differences were not significant at the end of the study. In terms of secondary outcomes, the ramus height shortening compared to the opposite side revealed favorable improvement in the Elastics group in the period of study. The differences between the two groups in the lateral movement and protrusive movement were significant in favor of the Elastics group. The differences in pain, fracture displacement, and midline deviation between study groups were not significant at the end of the study. Just 1 case with malocclusion was observed in the Wire group. Patients were more satisfied with dynamic nonrigid IMF with elastics. The results of this study showed that using the dynamic IMF technique is more tolerable, and patients have better functional and clinical outcomes during and at the end treatment.

Quality of life patients after treatment of mandibular fractures with ORIF in oral surgery departement of Dr. Sardjito general hospital

Management of mandibular fracture using open reduction Internal fixation (ORIF) method is one of the ideal treatments for single and multiple mandibular fractures. The aim of this study was to determine the quality of life of patients after the treatment of mandibular fractures with ORIF using miniplate in single and multiple mandibular fractures. This research used case-control by recalling 43 research subjects in the oral surgery department Dr Sardjito general hospital between 2013 and 2017, that consisted of patients suffering from 23 single fractures and 20 multiple mandibular fractures. Each fracture would be examined clinically and subjectively. Clinical examination parameters were conducted using the mandibular mobility index (MMI) consisting of mouth opening assessment, left and right lateral mandibular excursion, and mandibular protrusive movement. Subjective parameters were performed based on general oral health asseesment index (GOHAI) questionnaire to assess physiological aspects, psychosocial aspects, and pain. The results of the chi-square test statistic study showed that the quality of life of a patient with a single mandibular fracture was better than that of multiple mandibular fractures based on MMI and GOHAI examinations. It was concluded that patients with a single mandibular fracture had a younger age, longer time adaptation and have a better quality of life.

Will Closed Treatment Provide Better Mandibular Motion Than Open Reduction and Internal Fixation in Cases of Unilateral Displaced Subcondylar Fracture? A Systematic Review and Meta-Analysis

The aim of the present systematic review was to determine whether closed treatment (CLT) with intermaxillary fixation (IMF) is superior or equivalent to open reduction and internal fixation (ORIF) in the management of unilateral displaced subcondylar fractures regarding the range of mandibular motion. To address our question, we conducted a systematic review and meta-analysis of the reported data after a comprehensive manual and electronic database search of studies reported up to 2017 in the English language that had compared CLT and ORIF of mandibular condyle fractures in adults. The following outcomes were recorded: maximum interincisal opening (MIO), protrusive movement (PM), lateral excursion toward the fractured side (LEFS), and lateral excursion toward the nonfractured side (LENFS). The search resulted in 8 studies, 4 of which were included in the meta-analysis. The MIO and PM showed no statistically significant differences, with an effect size of -0.823 (P=.112) and -0.633 (P=.079), respectively. However, the LEFS and LENFS were superior after CLT, with an effect size of -0.710 (P=.031) and -0.682 (P=.017), respectively. The findings from the present review suggest that both ORIF and CLT can provide comparable MIO and PM in subjects with unilateral displaced subcondylar fractures. However, CLT was superior to ORIF for both LEFS and LENFS.

Noncanonical Wnt planar cell polarity signaling in lung development and disease.

The planar cell polarity (PCP) signaling pathway is a potent developmental regulator of directional cell behaviors such as migration, asymmetric division and morphological polarization that are critical for shaping the body axis and the complex three-dimensional architecture of tissues and organs. PCP is considered a noncanonical Wnt pathway due to the involvement of Wnt ligands and Frizzled family receptors in the absence of the beta-catenin driven gene expression observed in the canonical Wnt cascade. At the heart of the PCP mechanism are protein complexes capable of generating molecular asymmetries within cells along a tissue-wide axis that are translated into polarized actin and microtubule cytoskeletal dynamics. PCP has emerged as an important regulator of developmental, homeostatic and disease processes in the respiratory system. It acts along other signaling pathways to create the elaborately branched structure of the lung by controlling the directional protrusive movements of cells during branching morphogenesis. PCP operates in the airway epithelium to establish and maintain the orientation of respiratory cilia along the airway axis for anatomically directed mucociliary clearance. It also regulates the establishment of the pulmonary vasculature. In adult tissues, PCP dysfunction has been linked to a variety of chronic lung diseases such as cystic fibrosis, chronic obstructive pulmonary disease, and idiopathic pulmonary arterial hypertension, stemming chiefly from the breakdown of proper tissue structure and function and aberrant cell migration during regenerative wound healing. A better understanding of these (impaired) PCP mechanisms is needed to fully harness the therapeutic opportunities of targeting PCP in chronic lung diseases.

Postoperative outcomes of adult patients with sagittal fractures of mandibular condyle: Quantitative evaluation and retrospective factor analysis

PurposeWe attempted to adopt quantitative methods to precisely evaluate the surgical effect of sagittal fractures of mandibular condyle (SFMCs) and aimed to determine differences in postoperative results between different groups of patients. Materials and methodsPostoperative data of patients with SFMC were collected and quantitative evaluations of subjective, clinical and imaging results were performed. SPSS software was used to analyze the data, and certain factors (gender, age, unilateral or bilateral SFMCs, injury time) were analyzed by univariate analysis. ResultsForty-four postoperative patients were included with an average follow-up of 15.7 months. Averages of resting pain, moving pain, and chewing pain were all <10. Averages of maximum mouth opening, protrusion, and ipsilateral excursive movement were 42.20, 4.80, and 5.98 mm, respectively. Moreover, 85.71% of condylar healing and remodeling was good, and average condylar absorption was 1.52 mm. Early-operated patients (injury time ≤2 weeks) exhibited greater ipsilateral excursive movement, higher condylar index, and lesser condylar absorption than late-operated patients (injury time >2 weeks). Patients with unilateral SFMC showed greater protrusive movement and higher condylar index than those with bilateral SFMCs. ConclusionMost patients with SFMCs could obtain good subjective, clinical and imaging results by appropriate surgical treatment. Early surgery could improve postoperative outcomes.

MODERN METHODS OF PATIENTS TREATMENT WITH DENTITION DEFECTS COMBINED WITH FUNCTIONAL DISORDERS OF THE TEMPOROMANDIBULAR JOINT

The aim: The purpose of the research was to increase the efficiency of treatment at patients with dentition defects and functional disorders of the temporomandibular joint. Materials and methods: We examined 140 patients aged from 25 to 65 years with functional disorders of the temporomandibular joint, analysed there diagnostic models in the articulator and 3D scanner, used radiographic methods of examination and condylography. Results: The results of the conducted studies showed that in the 1st group, the biomechanical parameters of temporomandibular joint movements before treatment were significantly lower: 6,4 ± 0,2 mm and 6,8 ± 0,2 mm for right and left temporomandibular joint during protrusion movements; 7,8 ± 0,1 mm and 7,9 ± 0,2 mm during vertical movements; 6,7 ± 0,1 mm and 6,5 ± 0,2 mm during transversal movements. After 12 month of complex and prosthetic treatment with a help of non-removable dentures the magnitude of movements remains at the achieved level at all excursions. As a result, proposed by us comprehensive treatment of functional disorders of the temporomandibular joint is carried out in stages. The proposed design of an individual tire makes it possible to gradually increase the bite height and perfectly forms the occlusal ratio. After 6 and 12 months of the proposed treatment, we have found that the indicators of vertical and protrusion movements of articular heads at patients of 2nd group were significantly better than before treatment. Conclusions: The proposed design of an individual tire makes it possible to gradually increase the bite height and perfectly forms the occlusal ratio.

Effects of overdenture attachment systems with different working principles on stress transmission: A three-dimensional finite element study.

PURPOSEThe aim of the present study was to compare the stress distributions on the dental implants, abutments, and bone caused by different overdenture attachment types under functional chewing forces.MATERIALS AND METHODSThe 3D finite element models of the mandible, dental implants, attachment types, and prostheses were prepared. In accordance with a conventional dental implant supported overdenture design, the dental implants were positioned at the bone level in the canine teeth region bilaterally. A total of eight models using eight different attachment systems were used in this study. All the models were loaded to simulate chewing forces generated during the centric relationship (450 N), lateral movement (400 N), protrusive movement (400 N), and also in the presence of a food mass unilaterally (200 N). Stress outputs were obtained as the maximum principal stress and the equivalent von-Mises stress.RESULTSIn all attachment types, higher stress values were observed in the abutments, dental implants, and bone in the magnet attachments in different loading conditions. The highest stress values were observed among the magnet systems in the components of the Titanmagnetics model in all loading conditions (stresses were 15.4, 17.7, and 33.1 MPa on abutment, dental implant, and bone, respectively). The lowest stress value was observed in the models of Zest and O-Ring attachments.CONCLUSIONThe results of the present study implied that attachment types permitting rotation and tolerating various angles created lower stresses on the bone, dental implants, and abutments.

Assessment of the relationship between maximum occlusal force and median mandibular flexure in adults: A clinical trial study.

Aim:The narrowing of the mandible during opening and protrusion movements is defined as median mandibular flexure (MMF). MMF is caused by the attachment of mandibular muscles; therefore, it can be assumed that a greater amount of maximum occlusal force (MOF) may cause more flexion and could affect the survival of dental and implant restorations. The purpose of this study was to evaluate any relationship between MOF and MMF in a sample of adults.Settings and Design:In vivo – comparative study.Materials and Methods:In this descriptive, cross-sectional, nondirectional study, a sample of 90 volunteers were recruited (45 men and 45 women). MOF was measured by applying the strain gauge receptor to the first molar region, and MMF was measured by calculating the variation in the intermolar distance by a digital caliper with an accuracy of 0.01 mm using an impression and resulted in the stone cast during the maximum opening and closed-jaw positions. The body mass index (BMI) also was calculated.Statistical Analysis:Data were analyzed using the SPSS software (version 23) inferential and descriptive statistics, linear regression, and Pearson correlation coefficient. P < 0.05 was considered statistically significant.Results:There was no statistically significant relationship between MOF and MMF (P = 0.78), but there was a significant association between MOF and BMI (P < 0.001, r = 0.475) and gender.Conclusion:Although MOF and MMF are both important and effective factors in the success of prosthetic restorations, one cannot be expected by the other and both should be considered in the treatment plan separately.

Changes in mandibular and articular dynamics associated with surgical versus nonsurgical treatment of mandibular condylar fractures: a systematic review with meta-analysis.

The aim of this study was to evaluate the mandibular and articular dynamics and the presence of complications associated with surgical or nonsurgical treatments of condylar fractures. Clinical trials that compared open reduction internal fixation and maxillomandibular fixation in patients with condylar fractures were included. We performed an electronic search of PubMed, Scopus, Cochrane Library, Web of Science, and LILACS (Latin American and Caribbean Health Sciences) databases starting from February 2017 and updated in January 2019 and found 467 articles. We evaluated methodologic quality by using the criteria from Cochrane's Collaboration Tool. After independent screening of abstracts, we assessed the full texts of 88 articles; 9 studies were included for qualitative synthesis; but only 8 were included for the meta-analysis. Four studies were considered to have high risk of bias, and 5 were considered to have low risk. The risk ratio (RR=0.20; 95% confidence interval [CI] 0.13-0.32) was observed for complications. The quality of evidence, using GRADE software, was considered low for maximum mouth opening and protrusive movement and moderate for lateral excursion movement and complications. This review suggested that open reduction internal fixation and maxillomandibular fixation are effective. However, surgical treatment presented higher objective parameters. Nonsurgical treatment presented a high index of complications, such as malocclusion, pain and deviation.

Clinical outcomes of patients with bilateral anterior disc displacement without reduction and erosive change of the temporomandibular joint after performance of unilateral arthrocentesis and stabilisation splint therapy.

The efficacy of a combination treatment of arthrocentesis and stabilisation splint for patients with bilateral anterior disc displacement without reduction (ADDWoR) and erosive change of the TMJ remains controversial. To evaluate clinical outcomes of patients with ADDWoR and erosive change of the TMJ after performance of unilateral arthrocentesis and stabilisation splint therapy. A retrospective study of 44 patients (37 females, 7 males, mean age of 34years) with bilateral ADDWoR and erosive change of the TMJ were included in this study. Their clinical outcomes before and after arthrocentesis and stabilisation splint therapy were compared. Evaluation criteria were as follows: (a) Maximal mouth opening (MMO); (b) Right and left maximal lateral movement (RLM, LLM) and maximal protrusive movement (PM); (c) Visual analog scale (VAS) pain score during MMO, RLM, LLM and PM; and (d) VAS pain score during palpation of masticatory muscles. Wilcoxon signed-rank test, Mc Nemar test and paired t test were used for statistical analysis. Differences in VAS pain score between arthrocentesis and non-arthrocentesis sites were not statistically significant except MMO and LLM (P<.05) after 6months. Differences in mean VAS pain scores for all variables between before arthrocentesis and 6months follow-up in the arthrocentesis site were statistically significant. (P<.01). Unilateral arthrocentesis on more symptomatic TMJ and subsequent stabilisation splint therapy was highly successful for pain and achievement of normal range of mandibular movements in patients with both ADDWoR and bony change.

Retrospective evaluation of marginal bone loss around implants in a mandibular locator-retained denture using panoramic radiographic images and finite element analysis: A pilot study.

The follow-up of the peri-implant marginal bone loss is the most important criterion for the determination of implant success. The purpose of this study is to measure marginal bone loss using panoramic radiographic images (PRI) of patients treated using a mandibular, two implant-supported, locator-retained denture and to evaluate the compatibility of these findings with those of the finite element analysis (FEA). The PRI of patients who had a mandibular, two implant-supported, locator-retained denture were assessed, and the mesial and distal marginal bone loss of both right- and left-sided implants was measured. Mandibular and maxillary models, which have the features of bilateral balanced occlusion, were created. The surfaces of the generated models were converted in a computer-aided design model that could be transferred to the FEA software, and the forces were defined on contacts formed in maximum intercuspation, lateral, and protrusive movement position for bilateral balanced occlusion. The bone loss in the mesial and distal regions at the right- and left-sided implants was not statistically significant. Higher stresses were formed on the vestibular side under protrusive movement, on the lingual side under maximum intercuspation, on the distolingual side under left unilateral biting, and on the mesiolingual side under right unilateral biting in the FEA. According to FEA, peri-implant bone resorption may be higher in the buccal and palatal regions, implying that panoramic radiographs can be misleading in understanding the amount of peri-implant bone resorption.

Effect of Plasma Rich in Growth Factors Intra Articular Injection in Management of Patients with Internal Derangement of TMJ Using CT Guided Puncture versus Conventional Technique

Purpose: To evaluate effect of PRGF intra articular injection in patients with internal derangement of TMJ using CT guided versus conventional puncture technique. Materials and methods: Twenty patients with internal derangement without improvement by conservative treatment were divided into two groups: Group I: ten patients underwent arthrocentesis followed by PRGF injection using conventional puncture by anatomical landmarks. Group II: ten patients underwent arthrocentesis followed by PRGF injection using landmark and confirmed by CT. All patients were assessed preoperatively and postoperatively at 1week, 3 and 6 months for pain level, maximum interincisal opening, lateral, protrusive movements, joint tenderness and disk position with MRI after 6 months. Results: In both groups, all clinical variables showed statistical significant discrepancy postoperatively, the discrepancy between both groups was not statistically significant and MRI showed no statistical significant change in disc position. Conclusion: CT confirmed accurate position and depth within TMJ upper compartment in different views, allowed correction with less puncture trials and decreased learning curve of TMJ puncture but it is expensive, time consuming and not available in clinics. Anatomical landmarks is easy and representable method for TMJ puncture but blind technique and needs skill. Single injection of PRGF found efficient in the treatment of internal derangement of TMJ.