Mechanical behavior of titanium and zirconia abutments at the implant-abutment interface: A systematic review.

STATEMENT OF PROBLEM: Zirconia has become popular for dental implant abutments in the esthetic zone but can damage the implant connection interface. Studies have been conducted to compare zirconia abutments with conventional titanium abutments; however, a consensus or systematic review is lacking. PURPOSE: The purpose of this systematic review was to evaluate the performance of abutments made of zirconia and titanium in relation to wear and misfit at the implant-abutment interface. MATERIAL AND METHODS: Electronic databases (PubMed/MEDLINE, Embase, Web of Science) were independently searched by 2 researchers for relevant studies published up to June 2021. The population, intervention, comparison, outcome (PICO) question was "Do zirconia abutments cause greater wear at the implant-abutment interface than titanium abutments under occlusal forces?" Eligible studies included in vitro studies that evaluated changes in the surface of external and/or internal connections and single and/or multiple, screwed and/or cemented prostheses rehabilitated with titanium and zirconia abutments submitted to mechanical cycling. RESULTS: Nine studies were included for qualitative analysis. A total of 172 specimens were analyzed, 86 zirconia and 86 titanium abutments. In terms of wear on the implant connection surface, zirconia abutments caused more severe wear, more scratches, and more rounding of the hexagonal angles at the implant connection interface than titanium abutments. In terms of misfit at the connection interface, zirconia abutments showed greater misfit than titanium abutments. CONCLUSIONS: Zirconia abutments produce more wear at the titanium implant connection interface, titanium abutments showed better fit to the implant connection interface, and the fit can be influenced by the abutment manufacturing method.

The use of carrageenan for limiting the mandibular movement in rats: A preliminary experimental study

Purpose: The objective of this study was to evaluate if the carrageenan may be used for limiting the mandibular movement. Material and Methods: Eighteen adult male Wistar rats were used for the research, 20 ìl of carrageenan (4%) was infiltrated in the extra articular region, in front of the condyle to induce fibrosis. The rats were divided into groups according to the time of euthanasia (7, 15 and 30 days). Maximal mouth opening (MMO), mandibular deviation,initial and final weights were recorded and evaluated. After the euthanasia, the specimens were submitted to histological study in order to classify the inflammatory process using scores. Results: The mean differences between initial and final MMO were 1.50 mm, being greatest at the 7 days evaluation and lowest at 30 days, and were not statistically significant at any time. No mandibular deviation was observedat any of the times of evaluation. The histological scores tended to increase with time of evaluation from 7to 30 days, but without progression of the process.Conclusion: The study model permitted the development of fibrosis in the extra-articular region in the majority of the animals (AU)

Relationship between mandibular fracture and impacted lower third molar

Many studies have shown that the greatest risk of fracture of the mandibular angle is related to the presence of an unerupted lower third molar, based on the hypothesis that there is a decrease in the area of bone and absorption of the impact in this area, leading some surgeons to indicate its prophylactic removal in patients most exposed to the risk factors of facial trauma. On the other hand, other authors have observed a greater frequency of condylar fractures in patients without an impacted lower third molar. Purpose: The aim of this study was to relate the condylar and angle fracture with an unerupted lower third molar, taking into account the position of the tooth. Material and Methods: Panoramic radiographs were used to determine if the presence or absence of the third molar is related to the occurrence of mandibular fractures, such as angle and condylar fractures. Results: In a total of 43 patients with angle fractures, the greatest percentage had erupted teeth, and 41.9% had impacted teeth; however there was no significant difference between the fractured side and the tooth condition (p=0.350). There were 91 condylar fractures and in 42.9% the third molar was absent and in 40.7% the tooth was erupted . There was no significant difference between the fractured side and the tooth condition (p=0.852). Conclusion: The absence of an impacted third molar may increase the risk of condylar fractures and decrease the prevalence of mandibular angle fractures (AU)

Surgical treatment of temporomandibular joint ankylosis: Follow-up of 15 cases and literature review

Introduction: Ankylosis may be defined as the fusion of the articular surfaces with bony or fibrous tissue. The treatment oftemporomandibular joint ankylosis poses a significant challenge because of the high incidence of recurrence.Purpose: To report 15 cases treated by either gap arthroplasty, or the articular reconstruction technique using costochondralgrafts, coronoid process grafts or alloplastic condylar implants; evaluate the results of these surgeries and make a literaturereview.Methods: The sample was obtained from the records of the Oswaldo Cruz University Hospital (HUOC-UPE) of patientssubmitted to ankylosis treatment by alloplastic or autogenous graft between March 2000 and October 2006. Pre- and postoperativeassessment included a thorough history and physical examination to determine the cause of ankylosis, the maximalincisal opening, etiology and type of the ankylosis, recurrence rate and presence of facial nerve paralysis.Results: The mean maximal incisal opening in the preoperative period was 8.71 + 6.97 mm and in the postoperative periodit was 28.50 + 8.10 mm, the recurrence rate was 20% (n=3), and always occurred in ankylosis type IV.Conclusion: The articular reconstruction with alloplastic or autogenous grafts, or gap arthroplasty for the treatment of ankylosisis shown to be efficient in relation to the post-operative maximal incisal opening, recurrence and articular function (AU)

Frequency of positive aspirations in anesthesia of the inferior alveolar nerve by the direct technique

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Objectives: Evaluate the frequency of positive aspirations and complications resulting from anesthesia of the inferior alveolar nerve by the direct technique.Study design: The sample was composed of 138 anesthetic injections applied with Duflex syringes with reflux. Theanesthesia was applied in patients of both sexes of various ages for procedures in which such anesthesia would be necessary.Results: The results showed 4.3% of positive aspirations in vivo. When the percentages of positive aspiration on the right and left sides were compared, no significant association was found. A greater number of positive aspirations was observed in the 15-30-year-old age group. It is emphasized that the only type of complication associated with positive aspirations was hematoma.Conclusions: The percentage of positive aspirations from inferior alveolar nerve block by the direct technique issignificant, and for the most part they do not appear in the form of a thin thread, requiring great care on the part of the person applying the anesthesia

Herida de nervio facial seguida de cirugía para el tratamiento de anquilosis de la articulación temporomandibular / Facial nerve injury following surgery for the treatment of ankylosis of the temporomandibular joint

Objetivo: El propósito de este trabajo fue realizar un estudio longitudinal de una serie de casos, en los cuales se observó disfunción del nervio facial subsecuente a cirugía para el tratamiento de anquilosis temporomandibular.Diseño del estudio: La muestra estuvo compuesta por 13 pacientes de ambos géneros, en los cuales fueron realizados 18 abordajes quirúrgicos. Fue realizada una evaluación postoperatoria de la actividad motora del nervio facial, de acuerdo con la escala de House-Brackmann. Todos los pacientes fueron fotografiados y evaluados para los periodos de tiempo: 24 horas, 1 semana, 1 mes y 3 meses.Resultados: Los resultados mostraron que el porcentaje de casos de disfunción del nervio facial fue de 31%. Fue observado un aumento en la frecuencia de lesión nerviosa en los casos donde fue usada la técnica de artroplastia interposicional, asi como también que el 75% de los pacientes habían sido sometidos al menos a una intervención quirúrgica previa al estudio. Después de 3 meses todos los pacientes presentaban actividad normal del nervio facial.Conclusión: La frecuencia de lesión del nervio facial se relaciona al grado de dificultad quirúrgica determinda por el tipo de anquilosis. Las lesiones nerviosas mostraron un caracter temporal

Objective: The purpose of the present paper was to carry out a longitudinal study of a series of cases in which injury of the facial nerve was observed following surgery for the treatment of temporomandibular ankylosis.Study design: The sample was composed of 13 patients, both male and female, in whom 18 surgical approaches were made. A postoperative assessment of the motor function of the facial nerve was made in accordance with the House-Brackmann grading system. All the patients were photographed and assessed at the following postoperative times: 24 hours, one week, one month and three months.Results: The results showed that injury of the facial nerve occurred in 31% of the cases. An increase in the frequency of nerve injury was observed in the cases in which the interpositional arthroplasty technique was employed, as well as the fact that 75% of the patients had undergone at least one surgical intervention prior to the study. After three months all the patients displayed normal function of the facial nerve.Conclusion: The frequency of facial nerve injury is related to the degree of difficulty involved in the surgery determined by the type of ankylosis. The nerve lesions were shown to be of a temporary nature

Evaluation of lidocaine and mepivacaine for inferior third molar surgery

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Objective: The aim of this study was to compare 2 percents lidocaine and 2 percents ciento mepivacaine with 1:100,000 epinephrine for postoperative pain control. Study design: A group of 35 patients, both genders were recruited, whose had ages ranged from 13 to 27 years-old and had two inferior third molars in similar positions to be extracted. The cartridges were distributed to the patients according to a randomised pattern, where lidocaine was in the control group and mepivacaine in the experimental group. Results: Results showed no significant association between the anesthetics and postoperative pain, pulp sensibility after one hour, gender, tooth position and duration of the surgical procedure. Conclusions: It was shown that lidocaine and mepivacaine have similar time of anesthesia, they are adequate for surgical procedures that last one hour, and there was no difference between the two anesthetics in relation to the severety of post-operative pain

Glove perforation during oral surgical procedures

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Objective: The aim of this study was to determine the incidence of glove perforation among undergraduates and residents performing maxillofacial surgery and identify procedures associated with the perforations. Study Design: For this purpose, 200 pairs of surgical gloves were used. For inspecting the perforations, the gloves were filled with water, at least 500 ml. Results: Sixteen gloves (8%) were perforated, 8 (4%) by residents and 8 (4%) by undergraduate students. Only the residentsnoticed that 2 gloves (1%) were perforated and identified the object causing the perforation. The left hand was the more affected with 9 perforations (4.5%). The finger pulp was the region most affected with 12 perforations (6%). The perforated forefinger appeared in 8 gloves (4%), representing the highest incidence of perforations. Conclusion: We concluded there was no difference in surgical glove perforation between undergraduate students and residents, the incidence of perforations was greater in the left hand (nondominant hand) and the fingers in which most perforations occurred were the forefinger and the thumb

Facial nerve paralysis after impacted lower third molar surgery: A literature review and case report

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Facial nerve paralisys (FNP) is the most commom cranial nerve disorders and it results in a characteristic facial distortion that is determined in part by the nerves branches involved. With multiples etiologies, these included trauma, tumor formation, idiopathic conditions, cerebral infarct, pseudobulbar palsy and viruses. FNP during dental treatment is very rare and can be associated with the injection of local anesthetic, prolonged attempt to remove a mandibular third molar and subsequent infection. We report a case of a 21 years-old black woman who developed a Bell’s palsy after an impacted third molar surgery under local anaesthesia, present a FNP classificated like a grade IV by the House-Brackmann’s grading system. The treatment was based of prescription of a citidine and uridine complex (NÚCLEO CMP tm) one tablet twice per day and a close follow up. Three months later that had begining the treatment, the patient recovery her normal facial muscle activity

Tratamiento de la anquilosis de la articulación temporomandibular por artroplastia simple / Treatment of temporomandibular joint ankylosis by gap arthroplasty

Objetivo: El propósito de este trabajo es mostrar que la artroplastia simple mejora la apertura bucal al tratar la anquilosis temporomandibular. Pacientes y métodos: Fueron tratados ocho pacientes con anquilosis de la articulación temporomandibular por medio de artroplastia simple. Los pacientes fueron evaluados en el postoperatorio por un periodo por lo menos de veinticuatro meses (mínimo 24 y máximo 48 meses). Resultados: De los ocho pacientes (once articulaciones), cinco (62,5%) presentaron afectación unilateral y tres pacientes (37.5%) afectación bilateral de la ATM. La edad media fue de 20 años ± 9 (rango de 3 a 30 años). La máxima apertura bucal en el período preoperatorio fue de 9,25 ± 6,41 mm, mientras en el período postoperatorio fue de 29,88 ± 4,16 mm (p = 0.011). Se observó parálisis del nervio facial en dos pacientes (25%) la cual fue de carácter temporal. No se observó ninguna recurrenciaen nuestra serie. Conclusiones: El trauma fue la mayor causa de la anquilosis tempomandibular en nuestra muestra. La artroplastia simple mostró buenos resultados para el tratamiento de la anquilosis de la ATM

Purpose: The purpose of this paper is to show that gap arthroplasty improve mouth opening when treating TMJ ankylosis.Patients and methods: Eight patients with TMJ ankylosis were treated by gap arthroplasty. The patients were evaluated by at least twenty-four months (minimum 24 and maximum 48 months).Results: Of the eight patients (eleven joints), five (62.5%) had unilateral involvement and three patients (37.5%) had bilateral involvement. The mean age was 20 years ± 9 (range 3 to 30 years). The mean maximal incisal opening (MIO) in the preoperativeperiod was 9.25 ± 6.41 mm and in the postoperative period it was 29.88± 4.16 mm. The complication of temporary facial nerve paresis was encountered in two patients (25%). No recurrence was observed in our series. Conclusions: Trauma was the major cause of tempomandibular joint ankylosis in our sample. Gap arthroplasty showed good results when treating TMJ ankylosis

Temporomandibular joint arthrocententesis: evaluation of results and review of the literature.

AIM: This study was designed to investigate the effects of arthrocentesis on the improvement of internal derangement symptoms and jaw function in a series of patients with anterior disc displacement and closed lockjaw. PATIENTS AND METHODS: The study was based on a review of patients records before and after treatment using clinical examinations and radiographs. Visual analog scales were used to measure pain before and after arthrocentesis. Six patients (12 temporomandibular joints) with closed lock symptoms (2 cases) and internal derangements (4 cases) were treated at the Oswaldo Cruz Hospital. The mean follow-up was 11.5 months. RESULTS: The mean maximum vertical opening before treatment was 31.83 mm and after arthrocentesis was 36.50 mm. The visual analog scale for pain before treatment was 7 points (mean) and after arthrocentesis the mean was 4.3. CONCLUSION: Arthrocentesis was shown to be effective in reducing pain and increasing jaw motion in this series of cases.