Influence of bone quality on the mechanical interaction between implant and bone: A finite element analysis.

OBJECTIVES: To evaluate the influence of bone type in terms of bone density and cortical bone thickness, on the stresses induced by two implants under compressive and oblique loads. METHODS: A numerical simulation technique based on the finite element method was applied. Two implant types (M-12 and Astra Tech) were introduced in a model matrix whose geometry was extracted from a real CBCT radiograph of the posterior mandibular region. The Young's module and Poisson's coefficient of the bone qualities described by Misch were calculated. Loads with amplitude of 400 N were exerted in two directions: compressive and 15° oblique to 5 mm above the uppermost part of the implant. RESULTS: The von Misses variant was analysed. Both implant types presented greater tension in the ​​cortical bone area than in the ​​trabecular bone region under compressive loading. For the oblique load condition, the stresses obtained in the cortical zone were significantly higher than those registered as a consequence of compressive loads in both implant types. CONCLUSIONS: Regardless of bone type, the M-12 implants presented lower tensions in the cortical bone than did the Astra implants. The tensions recorded for D3 and D4 bone types in the trabecular zone surrounding the M-12 implants were greater than those recorded for the Astra implants. CLINICAL SIGNIFICANCE: For both compressive and oblique loads, good mechanical behaviour was observed. The decrease in bone quality determines a worse stress distribution, and the cortical bone is overloaded. An efficient distribution of the forces may increase the implants' longevity.

Postoperative effects on lower third molars of using mouthwashes with super-oxidized solution versus 0.2% chlorhexidine gel: A randomized double-blind trial

BACKGROUND: The main objective of the present study is to evaluate the effects and possible benefits with regard to the postoperative period of lower third molar extractions, comparing the intraalveolar application of a bioadhesive gel of 0.2% chlorhexidine (CHX) to the use of a mouthwash with a super-oxidized solution, (SOS) Dermacyn(R) Wound Care (Oculus Innovative Sciences lnc., California, USA). MATERIAL AND METHODS: A randomized double-blind study was carried out in 20 patients with a split-mouth design, with a total of 40 extractions of symmetrically impacted bilateral lower third molars. Patients were divided into two groups, a control group (C = 20) and an experimental group (D = 20). Any infectious complications, wound healing, plaque accumulation in the stitches, and presence of trismus and inflammation were evaluated using the distance between different facial points, at three, eight, and fifteen days after extraction. Pain, swelling, and amount of analgesics taken were evaluated using the VAS scale throughout the 15 days following extraction. Tolerance to treatment was evaluated using a verbal scale. Results were statistically compared using the Student's t- and chi-squared tests. RESULTS: No statistically significant differences were found between the two groups with regard to infectious complications, swelling, or wound healing. Use of analgesics and self-reported pain levels were slightly lower in the experimental group than in the control group during days 6 and 7 of the study (p< 0.05). The global treatment tolerance was satisfactory and similar in both groups. CONCLUSIONS: Both CHX and SOS are effective at improving the postoperative period after extraction of lower third molars

Effectiveness of flossing loops in the control of the gingival health.

BACKGROUND: One of the key factor in the good condition of periodontal tissues is their daily hygiene. Oral hygiene techniques such brushing and a good interdental hygiene by correct flossing are very important. The aim of this study is to compare the use of dental floss in a loop vs traditional floss in the control of Loe-Silness Gingival Index (IG), Turesky´s Plaque Index (IPT), Gingival Bleeding Index (IS) and the values of interleukin 6 (IL-6) and interleukin 8 (IL-8). MATERIAL AND METHODS: A comparative study of 40 patients in which each patient was his own control, using during 45 days each one of the devices (new loop floss and conventional floss) of interdental hygiene analysed. Data for Loe-Silness Gingival Index (IG), Turesky´s Plaque Index (IPT), Gingival Bleeding Index (IS) and the values of interleukin 6 (IL-6) and interleukin 8 (IL-8)were collected and measured in every visit for every type of interdental hygiene device. RESULTS: Our data indicates that the rate of Turesky´s Plaque Index presented statistically significant differences between groups (loop: 1.66 ± 0.8; traditional: 1.12 ± 0.8; p<0.0001). The rest of the indices studied showed no statistically significant differences. CONCLUSIONS: The creation of new dental floss designs try to make their use easier and more sensitive, and plaque removal more effective. The loop design can facilitate interdental hygiene, reaching similar effectiveness than traditional floss, improving some indicators, such as Turesky´s Plaque Index. Key words:Dental floss, bacterial plaque, loop floss, plaque index, periodontal diseases.

Fiabilidad del uso de la tomografía computarizada de haz cónico en la localización y medida del conducto mandibular en la planificación de técnicas quirúrgicas en el cuerpo mandibular / Reliability of cone beam computed tomography in locating and measuring the mandibular canal for planning of surgical techniques in the mandibular body

Objetivo. El objetivo de nuestro estudio fue determinar la fiabilidad del estudio tomográfico para localizar el conducto mandibular y tomar mediciones exactas del diámetro de dicho conducto y de la pared ósea vestibular, como mediciones principales en la planificación de la toma de injerto óseo de cuerpo mandibular. Material y método. Se estudiaron 11 mandíbulas (22 hemimandíbulas) de cadáver fresco, la mitad de ellas dentadas, a las cuales se les realizaron una CBTC y un procedimiento quirúrgico de lateralización del nervio dentario inferior con el objetivo de medir el grosor de la tabla vestibular y el grosor del conducto mandibular o dentario inferior (CDI) a los 5, 15 y 25 mm de la parte más posterior del agujero mentoniano. Resultados. Los resultados obtenidos por nuestro estudio indican que el CBTC, siendo el mejor método diagnóstico disponible en la actualidad, aún presenta diferencias respecto a la realidad. Esta discrepancia es de 1,15 mm de media con relación al grosor de la tabla ósea vestibular que lo recubre y de 0,3 m de media con relación al grosor del CDI. Discusión. Conocer y valorar estas discrepancias es importante dada la multitud de procedimientos quirúrgicos que se pueden realizar en esta zona, y la vecindad con el nervio dentario inferior (AU)

Aim. The aim of this study was to determine the reliability of cone beam computed tomography to locate and take measurements of the mandibular canal, as well as the vestibular bone wall, in the planning of the bone graft surgery in the mandibular body. Material and methods. A total of 11 mandibles from fresh cadavers were studied (22 hemi-mandibles, half of them with teeth). A CBTC and a surgical procedure for the lateralization of the lower dental nerve were performed with the aim of measuring the thickness of the vestibular table and the mandibular canal (MC) or lower dental nerve at 5, 15, and 25 mm from the most posterior position of the mentonian hole. Results. The results obtained in the study indicate that CBTC, being the best diagnostic tool currently available, still appears to be unreliable when compared to actual resultshas. This discrepancy is a mean of 1.15 mm as regards the thickness of the vestibular bone wall that covers the MC, and a mean of 0.3 mm in relation to the thickness of the lower dental nerve. Discussion. It is important to know and assess these discrepancies in view of the multitude of surgical procedures that can be performed in this area, and in the vicinity of the lower dental nerve (AU)

What Are the Histologic Effects of Surgical and Orthodontic Treatment on the Gingiva of Palatal Impacted Canines?

PURPOSE: To histologically evaluate changes in the marginal gingiva of palatal impacted maxillary canines after surgical exposure and orthodontic treatment. MATERIALS AND METHODS: A prospective case-and-control study was conducted of 10 patients presenting with bilateral palatal impaction of the maxillary canines. All patients underwent surgical exposure of the impacted canines with an open-window technique, which was followed by orthodontic treatment to achieve proper arch alignment. Once the treatment was finalized, 4 samples of marginal gingival tissue from each patient were taken for histologic study. The 4 samples consisted of 1 from each of the repositioned maxillary canines (case teeth) and 1 from each of their respective adjacent first premolars (control teeth). RESULTS: Histologic examination of the case teeth tissue samples showed microscopic changes mainly in the nonkeratinized epithelium and connective tissue, whereas changes in the keratinized epithelium remained minimal. The control teeth showed a greater inflammatory reaction in the nonkeratinized epithelium. CONCLUSION: Orthodontic treatment of impacted maxillary canines used in conjunction with an open-window surgical technique results in predictable orthodontic eruption with few periodontal discrepancies of the marginal gingiva compared with their adjacent first premolars.

The effects of informed consent format on preoperative anxiety in patients undergoing inferior third molar surgery

OBJECTIVES: To evaluate the effect of informed consent format on preoperative anxiety of patients. MATERIAL AND METHODS: We performed a prospective study (91 patients) undergoing lower third molar extraction. Patients were distributed into three groups. Informed consent for surgery was obtained through a written document, an oral interview or a video recording. Afterwards, patients were asked about their anxiety level and the effect the informed consent had had on it. RESULTS: Whereas the information conveyed both in oral and written formats relieved the patient to some extent (in a scale of -3 to +3) 0.97±1.21 and 0.29±0.97, respectively), the video recording increased patient's anxiety in a statistically significant way (in a scale of -3 to +3, -0.57±1.43). The difference obtained between the values obtained in oral and written information was not statistically significant. DISCUSSION: The most adequate format, according to our study, would be the oral format

The effects of informed consent format on preoperative anxiety in patients undergoing inferior third molar surgery.

OBJECTIVE: To evaluate the effect of informed consent format on preoperative anxiety of patients. MATERIAL AND METHODS: We performed a prospective study (91 patients) undergoing lower third molar extraction. Patients were distributed into three groups. Informed consent for surgery was obtained through a written document, an oral interview or a video recording. Afterwards, patients were asked about their anxiety level and the effect the informed consent had had on it. RESULTS: Whereas the information conveyed both in oral and written formats relieved the patient to some extent (in a scale of -3 to +3) 0.97 ± 1.21 and 0.29 ± 0.97, respectively), the video recording increased patient's anxiety in a statistically significant way (in a scale of -3 to +3, -0.57 ± 1.43). The difference obtained between the values obtained in oral and written information was not statistically significant. DISCUSSION: The most adequate format, according to our study, would be the oral format.