Strain Induced by Bio-High-Performance Polymers and Cobalt-Chromium Digitally Constructed Telescopic Partial Dentures after 1 Year Simulation of Function

BACKGROUND: Numerous attempts were made to reduce the adverse effects of the distal extension removable partial dentures (RPDs) and enhance their prognosis. High-performance polymers (HPP) were utilized in the construction of RPDs to maintain the health of the supporting structures. AIM: Thus, this study was prompted to compare the strains induced by Bio HPP and Cobalt- Chromium (Co Cr) Computer Assisted Design and Computer Assisted Manufacturing telescopic RPDs after 1 year of function. MATERIALS AND METHODS: A maxillary Kennedy class I was used in this study. Twelve telescopic RPDs were fabricated from two different materials. In Group A, six telescopic RPDs were milled from Co-Cr and in Group B, six telescopic retained RPDs were milled from Bio-HPP. Each partial denture was seated on the cast and introduced into the chewing simulator. The strain values were recorded using four strain gauges connected to a four-channel strain indicator. Statistical analysis of the resultant data was done using one-way ANOVA, followed by Tukey’s HSD for comparison within the same group. Student t-test was used for comparison between the different groups. The significance level was set at p ≤ 0.05. RESULTS: During unilateral loading, the results showed higher strains in Group A at the abutments (473.33 μm/m ± 10.8, 193.39 μm/m ± 10.8) and at the distal aspect of the ridge (470.83 μm/m ± 13.93, 185 μm/m ± 20.83) than Group B. Independent t-test showed statistically significant difference between strains at the abutments of both groups (t = 70.4, p ≤ 0.0001), (t = 36.84, p ≤ 0.0001). Furthermore, there was a statistically significant difference between strains at the saddles of both groups (t = 51.62, p ≤ 0.0001), (t = 34.72, p ≤ 0.0001) respectively (DOF = 10). CONCLUSIONS: In telescopic RPDs, Co Cr induces higher strain values on the abutments and the distal aspect of the ridge than Bio-HPP during bilateral and unilateral loading. During unilateral loading, Bio-HPP telescopic RPDs direct high strain values on the distal aspect of the ridge of the loaded side. CLINICAL IMPLICATIONS: The materials that induce less stresses on the supporting structures of telescopic partial dentures on the long-term can be used to maintain the health of periodontally affected abutments.

Comparison of radiographic changes in the alveolar crest after extraction of fully and partially erupted premolars during orthodontic treatment: A retrospective analytical study

Background. The alveolar process plays an essential role in providing dental support and gradually disappears with tooth loss. Space deficiency can cause one premolar to remain semi-erupted adjacent to a fully-erupted premolar. During orthodontic treatment, each of these premolars can be extracted. This retrospective study aimed to compare radiographic changes of the alveolar crest due to orthodontic movements of fully-erupted and semi-erupted premolars into the extraction sites before and after treatment. Methods. The patients were divided into the fully-erupted premolar extraction (first) group and the semi-erupted premolar extraction (second) group. The distance between the cementoenamel junction (CEJ) and the alveolar crest, from the distal aspect of the canine to the mesial aspect of the first molar, was measured on panoramic radiographs of 78 patients (39 from each group) before and after treatment with a digital caliper. Changes in the alveolar crest were compared between the two groups. Finally, the height differences of the alveolar crest in mesial and distal aspects of the remaining premolars in both groups were calculated at the end of treatment. Descriptive statistical analyses and paired and independent t tests were used in the study. Results. The distance from the CEJ to the alveolar crest at mesial and distal aspects in the first group and the distal aspect of the extraction site in the second group increased significantly. However, changes at the mesial aspect were not significant in the second group. Comparing the alveolar crest height between the two groups and between the mesial and distal aspects of the remaining premolar tooth indicated no significant differences. Conclusion. No significant difference was observed between the extraction of a fully-erupted or semi-erupted premolar to obtain greater alveolar height.

Suprabulbar Approach to Jugular Fossa Tumors: 2-Dimensional Operative Video

Owing to their scarcity, location, and intricate neurovascular associations, jugular fossa tumors are among the most challenging pathologies encountered by the neurosurgeon.1 While paragangliomas originate within and often occlude the jugular bulb, schwannomas and meningiomas are extra-bulbar and typically do not impede venous flow.2 Schwannomas typically arise from an extradural origin, expanding the jugular foramen.3-5 Meningiomas are intradural and cause hyperostosis of the jugular tubercle.6 We described and have been exposing and resecting jugular fossa tumors through a presigmoid suprabulbar infralabyrinthine window6 that has been detailed in cadaveric studies.7,8 This approach maintains the patency of the jugular bulb without breaching the labyrinths or manipulating the facial nerve. It is applicable to cases with partially impaired hearing and intact lower cranial nerves. The carotid artery can be identified by neuronavigation and micro-Doppler ultrasonography. This approach provides a direct lateral trajectory with a short distance to the jugular fossa and cerebellopontine angle. Early exposure and central debulking of the tumor minimize manipulation of the exquisitely sensitive lower cranial nerves. The distal aspect of these tumors can be removed with endoscopic assisted techniques.9 The first patient is a 49-yr-old woman with a previously irradiated schwannoma who presented with worsening neurologic deficits—an extradural suprabulbar approach was used to resect this tumor. The second patient is a 27-yr-old woman with an enlarging meningioma and associated neurological dysfunction; this tumor was resected using the suprabulbar approach with opening of the presigmoid dura. Both patients have consented to surgery and publication of images. Image at 2:27 and 6:38 reprinted from Arnautović et al, with permission from JNSPG. Image at 2:50 and 6:45 ©Ossama Al-Mefty 1997, reused with permission.

Residual Dentin Thickness in Bifurcated Maxillary Premolars after Cervical Preflaring Preparation: A CBCT Analysis

Objective: This study evaluated the residual dentin thickness (RDT) of maxillary premolars after the use of different cervical preflaring (PF) drills by using cone-beam computed tomography (CBCT). Methods: Eighty bifurcated maxillary premolars were accessed and randomly divided into 5 groups (n=16). PF was performed with Gates-Glidden #1, #2, and #3 (group 1), Largo #1 and #2 (group 2), and LA Axxess #20/.06 (group 3), #35/.06 (group 4), and #45/.06 (group 5). CBCT images were acquired before (preoperative) and after (postoperative) PF. Initial and final cervical dentin thickness was measured at the buccal, palatal, mesial, and distal aspects, 0.5 mm coronally to the furcation, on both buccal and palatal roots, using CBCT’s image analysis software. The percentage of removed dentin after PF preparation was also calculated. Data were analyzed using ANOVA followed by Tukey’s test at a significance level of P < 0.05. Results: No statistically significant differences were found among the groups for preoperative or postoperative RDT (P > 0.05). LA Axxess #20/.06 (group 3) removed significantly less cervical dentin at all root canal aspects on both buccal and palatal roots. The mesial aspect of the buccal root and distal aspect of the palatal root were significantly reduced after the use of LA Axxess #45/.06 (group 5) and Largo #1 and #2 drills (group 2), respectively (P < 0.05). Conclusion: PF in bifurcated maxillary premolars should be performed with LA Axxess instrument #20/.06. The use of Gates-Glidden #1, #2, and #3, Largo #1 and #2, and LA Axxess #45/.06 drills should be done with caution.

A pilot study on immediate loading dental implants

Evolution in the field of dental implantology made the replacement of missing tooth easy and quick. During initial phase of evolution, there was a need of 3 to 6 months of healing period to get teeth on implants but with advancement of technology and research, immediate replacement of missing teeth without waiting period could become a possibility. To access the efficacy of immediate loading in dental implantology using Hexacone® (IHDE DENTAL - Switzerland) dental implant. The objectives were to evaluate pain, infection, recession, loosening of abutment, fracture of implant/crown, de-cementation, peri-implant radiolucency, and marginal bone loss. Five patients (3 male and 2 female) who needed teeth replacement were included in the study. Among 5 patients, 3 patients needed single tooth replacement and the remaining 2 needed segmental replacement. Out of 7 implants 6 implants were placed in the healed bone and 1 was placed in the extraction socket. In case of healed bone, permanent prosthesis were given on 3 day. In case of extraction site, temporary acrylic crown was given on 2 day, which was replaced by permanent prosthesis after 3 month. These patients were evaluated at 7 day, 1 month, 3 months, 6 months and 12 months clinically and radiographically. Infection, prosthetic problems, peri-apical radiolucency, and implant mobility were not observed and marginal bone loss was observed during follow-up periods. On 6 months follow up, 0.5mm and 0.45mm marginal mean bone loss was observed on mesial and distal aspect respectively whereas the same was 1.24mm and 1.14 mm on 12 months follow-up respectively.The immediate loading for dental implants is a successful procedure that decreases the time for the patients to obtain a final restoration satisfying both esthetical and functional problems. Immediately loaded implants survive equally well in extraction socket. No significant difference was seen in survival when implants were placed in healed bone and extraction socket.

A Pilot Retrospective Study on the Effect of Bone Grafting after Wisdom Teeth Extraction

This study aimed to retrospectively investigate the effect of bone graft after extraction of wisdom teeth impacting with the distal aspect of the second molar, on soft tissue wound healing, bone loss, and periodontal parameters. Sixteen patients treated an for impacted mandibular wisdom tooth at least one year ago were re-called (18 teeth). Dental panoramic tomography and periodontal parameters were assessed. A graft material was used to fill the post-extractive sockets in the test group (GUIDOR easy-graft CRYSTAL), whereas in the control group, the socket was filled using a collagen sponge and blood clot (Hemocollagene, Septodont, Matarò, Spain). The radiographic bone loss was measured at the distal aspect of the second molar. The Wilcoxon singed-rank test for paired data was performed to evaluate statistical differences. In the test group, only two cases out of nine showed bone loss, with an average of 0.55 ± 1.30 mm. Conversely, in the control group, five teeth out of nine showed bone resorption with an average of 1.22 ± 1.30 mm. However, the differences were not statistically significant. Periodontal parameters at the second molar demonstrated similar behavior between the test and control groups. Soft tissue healing complications were lower in the grafted compared to the comparator sites without reaching statistical significance. Within the limitations of the present study, no difference was found between the two groups.

Bacillus Cereus Osteomyelitis in an Athlete: Case Report and Review of the Literature

Bacillus cereus is an aerobic Gram-positive, spore-forming rod, widely distributed in the environment. Although, most commonly known to cause gastrointestinal infections, B. cereus can also cause osteomyelitis and other deep-seated infections. Here we describe the case of an athlete who presented with B. cereus osteomyelitis following surgery for closed displaced mid shaft fracture of tibia and fibula sustained during a football match. The patient had internal reduction and fixation of the fracture; Cephazolin was given as prophylaxis. 9 weeks later he developed osteomyelitis, B. cereus was isolated from specimens collected during surgery which was treated with Teicoplanin and Ciprofloxacin. After initial improvement X-ray showed progressive posterior bone bridge at the site of the fracture and no obvious evolution of the distal aspect of the tibia in comparison with the previous radiography. The patient was then transferred to a referral hospital where he had another surgery to drain the pus and remove the intramedullary prosthesis. At this stage Clostridium aerotolerans and Propionibacterium acne were isolated from the tissues, treated successfully with metronidazole. Bacillus cereus osteomyelitis should be considered in the differential diagnosis for infection following limb trauma. It is prudent to use for prophylaxis Vancomycin or Teicoplanin in such situation instead of Cephazolin to which B. cereus is usually resistant due to the production of beta lactamases.

EFFECT OF LONG-TERM SPACE MISSIONS ON THE BIOMECHANICAL CHARACTERISTICS OF LOCOMOTIONS WITH AN ADDITIONAL MOTOR TASK

Goal of the investigation is extantion of our knowledge about the gravity-dependent changes in motor control due to a prolonged stay in the spaceflight conditions using the stepping-over-obstacle test. The paper presents mechanical characteristics of locomotions performed by 7 cosmonauts onboard the International space station in 171 ± 19 day missions. Subjects of analysis were time of standing on one leg and distance of the knee joint, ankle joint and distal aspect of foot elevation over the obstacle, as well as angles of the hip, knee and ankle joints of the leg first to step over. It was shown that after long space missions the stepping-over task was fulfilled with lowered joint amplitudes as compared to the pre-flight data. Time of standing on one leg and distance between the obstacle and leg first to step over were both increased considerably only at the hight of 30 cm.

Degloving injury of the distal aspect of the limb in a horse and preventing bone sequestrum formation using multiple, partial depth cortical fenestration

Exposed or denuded bone is a common complication of wounds of the distal aspect of the limb. This clinical report describes the treatment of an extensive laceration of the right hindlimb of a 12-year-old Hungarian Warmblood Horse gelding, which was managed initially by application of hydrogel dressings to enhance autolytic debridement, subsequently, by cortical fenestration of the denuded cortical bone and by stimulating the production of granulation tissue to cover the exposed bone. An early radiographic sign of sequestrum formation (discrete changes in the outer cortex) was not seen after the injury. Six weeks later, the wound was completely covered with vascularized, healthy-appearing bed of granulation tissue, which was prepared for grafting using the punch technique. A reinforced bandage was applied for the following 7 weeks; the grafts were accepted by granulation tissue. The horse was discharged 20 weeks after admission and the owners were advised to maintain stall rest with hand walking for two weeks. Four years later the owner reported that the wound had completely healed with a good cosmetic outcome and the horse was being used in a carriage.

Surgical extraction of the impacted mandibular third molar: Vestibular bone window technique

Introduction. Surgical extraction of impacted mandibular third molar can lead to the periodontal defect on distal aspect of the mandibular second molar causing pocket formation, tooth sensitivity, food retention, postoperative infections. Different surgical techniques have been proposed to reduce periodontal complications. Case Outline. We presented five cases treated with Vestibular Bone Window Technique. Considering data from the literature review, benefits and limitations of the technique are discussed and compared to the Standard Surgical Technique. Conclusion. Vestibular Bone Window Technique might be recommended surgical procedure for the extraction of impacted mandibular third molar when bucco-distal bone wall is present preoperatively. Taking into account only five cases, future work should consider a randomized clinical trial with the larger stratified samples.