Gelatin methacryloyl hydrogel with and without dental pulp stem cells for TMJ regeneration: An in vivo study in rabbits.

BACKGROUND: In the last decade, tissue-engineering strategies for regenerating the temporomandibular joint (TMJ) have been investigated. This may be a promising strategy for the minimally invasive restoration of joint integrity. OBJECTIVES: To evaluate whether dental pulp stem cells (DPSCs) loaded in a light-occured hydrogel made of gelatin methacryloyl (GelMA) enhance the regeneration of osteochondral defects in the rabbit TMJ. MATERIALS AND METHODS: Defects were filled with GelMA alone (control group; n = 4) or filled with GelMA loaded with rabbit DPSCs (experimental group; n = 4), In one group, the TMJ capsule was opened without creating a defect (sham group; n = 2). The following micro-CT parameters were analysed: bone volume to total volume ratio (BV/TV%) and bone mineral density (BMD). Histological evaluation was performed to assess cartilage regeneration features. A semi-quantitative scoring system was also used to evaluate the defects. RESULTS: All groups had no statistical difference regarding the micro-CT parameters. The highest mean healing score was found for the experimental group. After 4 weeks, there were no signs of hydrogel in either group or no signs of inflammation in the adjacent tissues. The tissue formed in the defect was dense fibrous connective tissue. CONCLUSION: Adding DPSCs to GelMA did not provide a regenerative enhancement in TMJ osteochondral defects. This resulted in similar micro-CT parameters after 4 weeks of healing, with improved signs of subchondral bone regeneration but no cartilage regeneration.

Mandibular shape prediction model using machine learning techniques.

OBJECTIVE: To create a mandibular shape prediction model using machine learning techniques and geometric morphometrics. MATERIALS AND METHODS: Six hundred twenty-nine radiographs were used to select the most appropriate craniomaxillary variables in different craniofacial pattern classifications using a support vector machine. To obtain the three-dimensional mandibular shape, a Procrustes fit was used on 55 tomograms, in which 17 three-dimensional landmarks were digitized. A partial least square regression was employed to find the best covariation between craniomaxillary angles and the symmetric components of mandibular shape. The model was applied to a new sample of six tomograms and evaluated by the mean absolute error. Each mandible predicted was assessed using the Hausdorff distance (HDu) and a color scale. The model was also exploratively applied to six new radiographs. RESULTS: Covariation was 88.66% with a significance of < 0.0001 explained by twelve craniomaxillary variables. Low differences between the original and predicted models were obtained, with a mean absolute error of 0.0143. The mean distance between meshes ranged from 0.0033 to 0.0059 HDu and each color scale demonstrated general similarity between the surfaces. CONCLUSIONS: This approach offered promising results in obtaining a mandibular prediction model that enhances shape properties in an economical way and is applicable to a Latin American population. Clinical proof of this method will require further studies with larger samples. CLINICAL RELEVANCE: This method offers a reliable, economic alternative to traditional mandibular prediction methods and is applicable to the Latin American population.

Differences in skeletal growth patterns: an exploratory approach using elliptic Fourier analysis.

OBJECTIVE: Apply elliptic Fourier analysis to find shape differences among the hypodivergent, normodivergent, and hyperdivergent growth patterns in skeletal classes I, II and, III in mandibular and maxillary curves and evaluate the discriminatory capacity of these differences. MATERIALS AND METHODS: A total of 626 adult patients were included: 354 Brazilian patients (52 with tomographic information and 302 with radiographic information) and 272 Colombian patients with radiographic information. Lateral views were selected. The maxillary and mandibular curves were digitized. Elliptic Fourier analysis was employed considering with 20 harmonics as well as filtering size, rotation, and translation properties. One-way non-parametric MANOVA was employed to determine differences. A confusion matrix tool was employed to analyze the discriminatory capacity of the model. RESULTS: Significant shape differences in the mandibular and maxillary contours were found among the hypodivergent, normodivergent, and hyperdivergent growth patterns in classes I, II, and III (p < 0.05). The accuracies obtained from the confusion matrix were respectively 74.1, 79.5, and 90.1% in classes I, II, and III in the mandibular curves and respectively 71.9, 73.9, and 75% in classes I, II, and III in the maxillary curves. CONCLUSIONS: Elliptic Fourier analysis can be used to find shape differences with an acceptable discriminatory capacity, especially in the mandible contour. Maxillary and mandibular bone curves each significantly defined facial biotypes regardless of the size and position properties. CLINICAL RELEVANCE: This exploration offers a way to quantify mandibular morphology for the construction of an economic mandibular prediction system applicable to the Latin American population.

A rabbit model to investigate temporomandibular joint osteochondral regeneration.

OBJECTIVE: The objective of this study was 2-fold: (1) to describe the rabbit temporomandibular joint (TMJ) anatomy and (2) to provide a detailed, step-by-step description of a minimally invasive approach to perform a standard osteochondral TMJ defect that can be used to investigate the regenerative potential of biomaterials. STUDY DESIGN: This study was performed in 2 steps. In the first, a total of 8 rabbit carcasses (n = 16 joints) were used to study the normal TMJ anatomy and histology to develop a minimally invasive approach to access the articulating surface of the condyle to perform a standard osteochondral defect. In the second, the surgical procedure was performed in 10 live animals to evaluate the feasibility of the model and to evaluate the regenerative potential of a biodegradable light-cured hydrogel seeded with stem cells (results not shown). RESULTS: The cartilage of the mandibular condyle showed 4 layers: fibrous, proliferative, hypertrophic, and a zone of calcified cartilage. Positive safranin O staining was observed in the cartilage. The mean duration of the procedure (from incision to last stitch) was 35.5 (±9.21) minutes. All animals survived the procedures without any major complications. CONCLUSIONS: This animal model represents an easy and nonmorbid surgical approach to rabbit TMJ.

Methodological quality of systematic reviews analyzing the use of laser therapy in restorative dentistry.

The purpose of this study was to identify systematic reviews (SRs) that compared laser with other dental restorative procedures and to evaluate their methodological quality. A search strategy was developed and implemented for MEDLINE, the Cochrane Library, LILACS, and the Brazilian Dentistry Bibliography (1966- 2007). Inclusion criteria were: the article had to be an SR (+/- meta-analysis); primary focus was the use of laser in restorative dentistry; published in English, Spanish, Portuguese, Italian, German. Two investigators independently selected and evaluated the SRs. The overview quality assessment questionnaire (OQAQ) was used to evaluate methodological quality, and the results were averaged. There were 145 references identified, of which seven were SRs that met the inclusion criteria (kappa=0.81). Of the SRs, 71.4% appraised lasers in dental caries diagnosis. The mean overall OQAQ score was 4.4 [95% confidence interval (CI) 2.4- 6.5]. Of the SRs, 57.1% had major flaws, scoring < or = 4. SR methodological quality is low; therefore, clinicians should critically appraise them prior to considering their recommendations to guide patient care.

Efficacy of proportional versus high condylectomy in active condylar hyperplasia - A systematic review.

OBJECTIVE: To perform a systematic literature review to test the efficacy of proportional condylectomy versus high condylectomy in patients with active condylar hyperplasia, in terms of avoiding secondary surgeries. METHOD: Following a search of Medline (Pubmed), Embase, Scopus, Web of Science and Cochrane databases, ten studies were included for qualitative analysis, and two studies were included for meta-analysis. Quality assessment was performed using the Newcastle-Ottawa scale for cohort studies and the 18-item modified Delphi technique for case series. RESULTS: 259 patients were included in the qualitative analysis, with a weighted arithmetic mean age of 20.4 years, and a female:male ratio of 2:1. Meta-analysis was carried out for 52 patients, and it was found that proportional condylectomy reduced the need for secondary surgery (p = 0.0003). Although this evidence had limitations, excised bone on proportional condylectomy was superior when compared with excised bone on high condylectomy, re-establishing the occlusal plane, resulting in fewer asymmetries, and therefore reducing the need for further surgery. CONCLUSIONS: This systematic review showed a tendency for proportional condylectomies to avoid additional surgeries; however, more comparative studies are necessary.

The methodological quality of systematic reviews comparing temporomandibular joint disorder surgical and non-surgical treatment.

BACKGROUND: Temporomandibular joint disorders (TMJD) are multifactor, complex clinical problems affecting approximately 60-70% of the general population, with considerable controversy about the most effective treatment. For example, reports claim success rates of 70% and 83% for non-surgical and surgical treatment, whereas other reports claim success rates of 40% to 70% for self-improvement without treatment. Therefore, the purpose of this study was to (1) identify systematic reviews comparing temporomandibular joint disorder surgical and non-surgical treatment, (2) evaluate their methodological quality, and (3) evaluate the evidence grade within the systematic reviews. METHODS: A search strategy was developed and implemented for MEDLINE, Cochrane Library, LILACS, and Brazilian Dentistry Bibliography databases. Inclusion criteria were: systematic reviews (+/- meta-analysis) comparing surgical and non-surgical TMJD treatment, published in English, Spanish, Portuguese, Italian, or German between the years 1966 and 2007(up to July). Exclusion criteria were: in vitro or animal studies; narrative reviews or editorials or editorial letters; and articles published in other languages. Two investigators independently selected and evaluated systematic reviews. Three different instruments (AMSTAR, OQAQ and CASP) were used to evaluate methodological quality, and the results averaged. The GRADE instrument was used to evaluate the evidence grade within the reviews. RESULTS: The search strategy identified 211 reports; of which 2 were systematic reviews meeting inclusion criteria. The first review met 23.5 +/- 6.0% and the second met 77.5 +/- 12.8% of the methodological quality criteria (mean +/- sd). In these systematic reviews between 9 and 15% of the trials were graded as high quality, and 2 and 8% of the total number of patients were involved in these studies. CONCLUSION: The results indicate that in spite of the widespread impact of TMJD, and the multitude of potential interventions, clinicians have expended sparse attention to systematically implementing clinical trial methodology that would improve validity and reliability of outcome measures. With some 20 years of knowledge of evidence-based healthcare, the meager attention to these issues begins to raise ethical issues about TMJD trial conduct and clinical care.

Efficacy of Dental Bleaching with Whitening Dentifrices: A Systematic Review.

A systematic review was performed to evaluate whether whitening toothpastes promote tooth whitening when compared to the use of conventional (nonbleaching) dentifrices. This review was registered at PROSPERO (CRD42017065132) and is based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Electronic systematic searches of PubMed/MEDLINE, Scopus, and the Cochrane Library were conducted for published articles. Only randomized clinical trials in adults that compared the use of so-called whitening dentifrices to the use of nonwhitening dentifrices were selected. The outcome was tooth color change. Twenty-two articles from 703 data sources met the eligibility criteria. After title and abstract screening, 16 studies remained, after which a further five studies were excluded. In total, nine studies were qualitatively analyzed. Significant differences in tooth color change were found between the groups using whitening dentifrices and those using nonwhitening dentifrices. Within the limitations of this study, the evidence from this systematic review suggests that bleaching dentifrices have potential in tooth whitening. However, although many whitening dentifrices have been introduced into the dental market for bleaching treatments, it is important to analyze tooth surface and color changes when performing home bleaching.

Comparative study of eminectomy and use of bone miniplate in the articular eminence for the treatment of recurrent temporomandibular joint dislocation.

UNLABELLED: Dislocation of the temporomandibular joint occurs when the mandibular condyle exits the glenoidal cavity and remains anteriorly locked to the articular eminence. It is repetitive (recurrent dislocation), usually associated with mandibular hypermobility and inclination of the articular eminence. AIM: This study intended to clinically and radiologically assess the technique of eminectomy and the use of a miniplate on the articular eminence for the treatment of recurrent dislocation of the temporomandibular joint of patients operated on at Oswaldo Cruz University Hospital from January to September 2003. STUDY DESIGN: Retrospective cohort. MATERIAL AND METHOD: The sample consisted of 11 patients. Eminectomy was performed on nine joints of five patients and the placement of a miniplate on the articular eminence was performed on 11 joints of six patients. Data collection was carried out through analysis of patient's medical charts and new postoperative visit. RESULTS: The results showed that there were no major postoperative complications with either technique. Maximum mouth opening was greater with eminectomy procedure and none of the patients operated on presented any recurrence of dislocation. CONCLUSION: It is concluded that both techniques were effective in the treatment of recurrent dislocation of the temporomandibular joint.

Treatment of large ameloblastic fibroma: a case report.

Ameloblastic fibroma (AF) is an extremely rare true mixed benign tumor that can occur in either the mandible or the maxilla, but is most frequently found in the posterior region of the mandible. It usually occurs in the first two decades of life and is associated with tooth enclosure, causing a delay in eruption or altering the dental eruption sequence. AF is diagnosed on routine radiographic evaluation and is clinically and radiographically similar to ameloblastic fibrodontoma and odontoma, which makes an accurate diagnosis mandatory. There is controversy in the literature as to whether treatment should be conservative or agressive. A conservative treatment strategy, such as enucleation and curettage, is usually sufficient. However, extensive lesions require radical treatment. We describe a case of ameloblastic fibroma with a very unusual clinical manifestation: it demonstrated considerable extension but no associated impacted tooth, was located in the anterior region of the mandible, and became symptomatic in the fifth decade of life. A radical surgical approach was taken, with immediate reconstruction.

Clinical and histopathologic study of the use of gangliosides for nerve regeneration in rats after axonotmesis.

PURPOSE: This study involved a clinical and histopathologic evaluation of the use of gangliosides in nerve regeneration, using an experimental model with higher vertebrates. MATERIALS AND METHODS: Forty Sprague Dawley rats had their right sciatic nerve crushed for 1 minute in a hemostatic tweezer. The animals were divided into experimental and control groups. The animals in the experimental group received an intramuscular injection of gangliosides in the left thigh for 25 days, whereas those in the control group received infiltrations of distilled water. A clinical evaluation of gait was made 24 hours and then 45 days after the surgical intervention, and a histopathologic evaluation of the sciatic nerves was performed after 45 days. RESULTS: There were no signs that the use of gangliosides significantly altered the animals' gait after 45 days. The animals in the experimental group had a greater frequency and intensity of inflammatory response than seen in the control group. CONCLUSION: The systemic use of gangliosides produced no improvement in gait and led to a more frequent and intense inflammatory response at the site of injury.

Estudo comparativo da eminectomia e do uso de miniplaca na eminência articular para tratamento da luxacão recidivante da articulacão temporomandibular / Comparative study of eminectomy and use of bone miniplate in the articular eminence for the treatment of recurrent temporomandibular joint dislocation

A luxacão da articulacão temporomandibular ocorre quando o côndilo mandibular move-se para fora da cavidade glenóide e permanece travado anteriormente à eminência articular, sendo sua ocorrência repetitiva (luxacão recidivante) geralmente associada a hipermobilidade mandibular e a inclinacão da eminência articular. OBJETIVO: Neste estudo avaliou-se, clínica e radiograficamente, a técnica de eminectomia e do uso de miniplaca na eminência articular para tratamento da luxacão recidivante da articulacão temporomandibular de pacientes operados no Hospital Universitário Osvaldo Cruz (HUOC/UPE), no período de janeiro de 2001 a setembro de 2003. FORMA DE ESTUDO: Retrospectivo. MATERIAL E MÉTODO: A amostra foi composta por 11 pacientes. A cirurgia de eminectomia foi realizada em nove articulacões de cinco pacientes, enquanto a cirurgia para colocacão de miniplaca na eminência articular em 11 articulacões de seis pacientes. A obtencão dos dados foi efetuada através da análise de prontuários e de nova consulta pós-operatória. RESULTADOS: Os resultados mostraram não haver maiores complicacões pós-operatórias para as duas técnicas. A abertura bucal máxima foi maior nos pacientes operados pela técnica de eminectomia e nenhum dos pacientes apresentou recorrência da luxacão. CONCLUSAO: Concluiu-se que as duas técnicas mostraram-se eficientes para o tratamento da luxacão recidivante da articulacão temporomandibular.