Effect of Steam Heat Sterilization on the Accuracy of 3D Printed Surgical Guides.

INTRODUCTION: Steam heat sterilization could be one of the factors that affects the dimensional accuracy of surgical guides, leading to an error during guided implant surgery. OBJECTIVE: The purpose of this study was to investigate the effect of steam heat sterilization on the dimensional changes of surgical guides. MATERIALS AND METHODS: A total of 27 surgical guides, which were made by either Formlabs printer (Formlabs Inc., Somerville, MA) or Simplant (DENTSPLY Implants NV, Hasselt, Belgium), were scanned using an intraoral scanner before and after sterilization. The dimensional changes at the center of the implant sleeves were analyzed using the computer-aided design interactive software for 65 implant sites before and after steam heat sterilization at 121°C for 20 minutes. RESULTS: There was no significant difference between the mean x, y, and z axes of the center of the sleeves when measured before and after sterilization (P values were 0.37, 0.24, and 0.29, respectively). Nonparametric analysis showed no significant difference between the mean deviations of either surgical guide (P = 0.908). CONCLUSION: Steam heat sterilization has a nonsignificant effect on the dimensional changes of the tested surgical guides.

Influence of surgeon experience on the accuracy of implant placement via a partially computer-guided surgical protocol.

PURPOSE: There is always a tension between allowing novice trainees to place implants independently and the need to achieve accurate functional and esthetic outcomes. The aim of this study was to measure the influence of surgeon experience on the accuracy of implant placement using a teeth-supported surgical guide via a partially guided surgical protocol. MATERIALS AND METHODS: Twenty partially edentulous patients were randomly allocated to expert and novice surgeon groups. Implant drilling and placement for the two groups were performed through a flapless surgical technique using surgical guides following a partially guided surgical protocol. The study primary independent variable was the surgeon experience, while the outcome variable was the accuracy, which was measured based on the differences in implant angulations preoperatively and postoperatively. Two-way analysis of variance (ANOVA) was applied to find the influence of surgeon experience, implant size, and the interactive effect of surgeon experience and implant size on the angular deviation. RESULTS: A total of 40 implants were inserted in 7 men and 13 women. There was no significant difference (P = .453) in the mesiodistal deviation between the expert and novice groups. In a buccolingual direction, the expert group performed more accurate implant placement (3.7 ± 3.35) compared with the novice surgeons (8.5 ± 6.3). CONCLUSION: The level of surgeon experience affects the accuracy of implant placement using a teeth-supported surgical guide; therefore, the use of computer-guided surgery via a partially guided protocol does not completely compensate for the level of operator experience. However, such surgical guide might be used in a whole task training of novice surgeons, as it can bridge the gap between simulation training in vitro and freehand surgery in a clinical setting.

Collaborative use of virtual patients after a lecture enhances learning with minimal investment of cognitive load.

BACKGROUND: The use of virtual patients (VPs), due to their high complexity and/or inappropriate sequencing with other instructional methods, might cause a high cognitive load, which hampers learning. AIM: To investigate the efficiency of instructional methods that involved three different applications of VPs combined with lectures. METHOD: From two consecutive batches, 171 out of 183 students have participated in lecture and VPs sessions. One group received a lecture session followed by a collaborative VPs learning activity (collaborative deductive). The other two groups received a lecture session and an independent VP learning activity, which either followed the lecture session (independent deductive) or preceded it (independent inductive). All groups were administrated written knowledge acquisition and retention tests as well as transfer tests using two new VPs. All participants completed a cognitive load questionnaire, which measured intrinsic, extraneous and germane load. Mixed effect analysis of cognitive load and efficiency using the R statistical program was performed. RESULTS: The highest intrinsic and extraneous load was found in the independent inductive group, while the lowest intrinsic and extraneous load was seen in the collaborative deductive group. Furthermore, comparisons showed a significantly higher efficiency, that is, higher performance in combination with lower cognitive load, for the collaborative deductive group than for the other two groups. CONCLUSION: Collaborative use of VPs after a lecture is the most efficient instructional method, of those tested, as it leads to better learning and transfer combined with lower cognitive load, when compared with independent use of VPs, either before or after the lecture.

The effectiveness of integration of virtual patients in a collaborative learning activity.

BACKGROUND: Virtual patients (VPs) have been recently integrated within different learning activities. AIM: To compare between the effect of using VPs in a collaborative learning activity and using VPs in an independent learning activity on students' knowledge acquisition, retention and transfer. METHODS: For two different topics, respectively 82 and 76 dental students participated in teaching, learning and assessment sessions with VPs. Students from a female campus and from a male campus have been randomly assigned to condition (collaborative and independent), yielding four experimental groups. Each group received a lecture followed by a learning session using two VPs per topic. Students were administrated immediate and delayed written tests as well as transfer tests using two VPs to assess their knowledge in diagnosis and treatment. RESULTS: For the treatment items of the immediate and delayed written tests, females outperformed males in the collaborative VP group but not in the independent VP group. CONCLUSION: On the female campus, the use of VPs in a collaborative learning activity is more effective than its use as an independent learning activity in enhancing students' knowledge acquisition and retention. However, the collaborative use of VPs by itself is not enough to produce consistent results across different groups of students and attention should be given to all the factors that would affect students' interaction.

Effects of sunitinib targeted chemotherapy on the osseointegration of titanium implants.

Targeted chemotherapies are novel therapeutic approaches for many malignancies. In contrast to conventional chemotherapies, which are given for a predetermined duration, treatment with targeted chemotherapies like sunitinib is routinely continuous over longer periods, sometimes years. During this prolonged treatment period, patients may need to restore their missing teeth with dental implants. The aim of this study was to examine the effect of the anti-angiogenic substance sunitinib targeted chemotherapy on the osseointegration of titanium implants in a rabbit model. Fourteen white New Zealand rabbits were randomly assigned to two groups of either oral sunitinib at 10 mg/kg twice per week dose for 4 weeks (n = 7) or placebo (n = 7). The first dose was given 2 days before the surgical intervention. Each rabbit received one titanium dental implant in the right distal femoral condyle. Four weeks following implant insertion, rabbits were sacrificed and bone specimens containing the implants were retrieved. Osseointegration of the implants was analyzed using micro-computed tomography and histomorphometric evaluation. Both micro-computed tomography and histomorphometric analysis showed that the osseointegration parameters, including the ratio of bone volume to total volume and bone-implant contact percent for the sunitinib group were significantly lower than those in the control group (P ≤ 0.05). Sunitinib targeted chemotherapy had a negative effect on the osseointegration of titanium implants inserted in a rabbit model.

Critical Size Defects for Bone Regeneration Experiments in the Dog Mandible: A Systematic Review.

OBJECTIVES: To perform a systematic literature review of studies involving critical size defects (CSDs) in the dog mandible and calvarium to find out the common characteristics of CSDs. MATERIALS AND METHODS: Internet search of the literature was performed on June 2016 based on specific keywords. The search process included 5 databases. The Animal Research Reporting In Vivo Experiment (ARRIVE) guidelines was used to assess the quality of the included studies. RESULTS: Nine studies have met the inclusion criteria and subjected to quality evaluation. All the defects (N = 156) were located in the mandible. Only 2 articles showed randomized controlled studies, whereas the remaining 7 were nonrandomized controlled studies. The geometry of the defects was either rectangular, box, cylindrical (circular), arch, or saddle shaped. CONCLUSION: There is a lack of homogeneity in reporting data on CSDs in the dog mandible. Future animal studies should include a negative control group for an objective comparison and evaluation of any new biomedical materials. More awareness is needed for the Animal Research Reporting In Vivo Experiment (ARRIVE) guidelines to improve data reporting, which can facilitate comparison and reproducibility of future studies.

Alveolar bone density and its clinical implication in the placement of dental implants and orthodontic mini-implants.

OBJECTIVES: To assess the bone density in maxilla and mandible in dentate and edentulous patients in Saudi population. METHODS: This study involved a retrospective analysis of cone beam CT images of 100 patients (50 male and 50 female) who have come to College of Dentistry, University of Dammam, Dammam, Kingdom of Saudi Arabia between January 2014 and 2015. Using the bone density option in the Simplant software, the Hounsfield unit (HU) was calculated at the edentulous sites. While for dentate sites, a region of interest was selected coronally at 3-5 mm to the root apex using I-CAT vision software. The densities of the buccal bone and cancellous bone were measured at interradicular areas of a specific teeth.  RESULTS: The highest bone density at the edentulous sites was at the mandibular anterior region (776.5 ± 65.7 HU), followed by the mandibular posterior region (502.2 ± 224.2 HU). Regarding the dentate sites, the highest bone density was at the buccal cortical plate of the lower incisor teeth (937.56 ± 176.92 HU) and the lowest bone density was at the cancellous bone around the posterior maxillary teeth (247.12 ± 46.75 HU).  CONCLUSION: The alveolar bone density at dentate and edentulous sites in our population is generally lower than the norm reference density of other populations, which dictates the need for quantitative assessment of bone density before implants and mini-implants placement.

Effects of cisplatin chemotherapy on the osseointegration of titanium implants.

PURPOSE: The effect of chemotherapy on the osseointegration of dental implants has received less interest compared with radiotherapy. Thus, the aim of the current study was to investigate the effect of cisplatin chemotherapy on the osseointegration of dental implants in a rabbit model. MATERIALS AND METHODS: Sixteen New Zealand White rabbits were randomly assigned to two groups of treatment of either cisplatin at 2.5 mg/kg/week for 4 weeks (n = 8) or placebo (n = 8), in which the first dose was administered 2 days prior to the surgical procedure. Each rabbit received one titanium dental implant inserted in the right distal femoral condyle. Four rabbits from each group were sacrificed 4 and 8 weeks after implant insertion. Osseointegration of the dental implants was analysed using micro-computed tomography and histomorphometric evaluation. RESULTS: Analysis of micro-computed tomography data and histomorphometric data showed that the osseointegration parameters, including the ratio of bone volume to total volume (BV/TV) and bone-implant contact (BIC%) for the cisplatin group, were significantly lower compared to the control group at 4 and 8 weeks. (P ≤ 0.05). CONCLUSION: Cisplatin chemotherapy had a negative effect on the osseointegration of dental implants when inserted throughout the chemotherapeutic regimens in a rabbit model.

Medical litigation in oral surgery practice: lessons learned from 20 lawsuits.

The aim of this study was to investigate all the lawsuits related to oral surgery practice over a period of three years, and to analyze the different causes of litigation. Inclusion criteria involved all the closed cases that proved malpractice against an oral and maxillofacial surgeon or involved a dentist who performed an oral and maxillofacial surgical procedure. The most common causes of litigation were oro-antral communication, neurological deficit, and bleeding. The study presented the lessons learned from 20 cases, and concluded that most of the lawsuits in oral surgery practice can be prevented either through preoperative measures or by dealing with the impact of the surgical error through good patient rapport and communication.

Does grafting of third molar extraction sockets enhance periodontal measures in 30- to 35-year-old patients?

PURPOSE: This study was designed to evaluate the use of xenograft plus a membrane as grafting material for periodontal osseous defects distal to the mandibular second molar compared with nongrafted extraction sites after removal of impacted mandibular third molars. MATERIALS AND METHODS: We performed a single-blind, randomized, controlled clinical trial, and the sample comprised of subjects at high risk for the development of periodontal osseous defects distal to the second molar after third molar extraction (aged 30-35 years), pre-existing osseous defects distal to the second molar, and horizontal third molar impaction. The predictor variable was the treatment status of the second molar osseous defects. The third molar extraction sites were grafted with an anorganic xenograft plus a membrane. The other sites received a full-thickness flap and extraction of the third molar without placement of the grafting materials. The outcome variables were the change in gingival index, pocket probing depth, and clinical attachment level on the distobuccal aspect of the second molar preoperatively and at 3, 6, 9, and 12 months after surgery. Data were statistically analyzed by multivariate analysis of variance, and the statistical significance was set at P < .05. RESULTS: The study was composed of 28 sites that were selected by use of a split-mouth design for each patient, and this was randomly determined through a biased coin randomization. Twelve months after third molar removal, there was a statistically significant gain in the clinical attachment level and a reduction in the probing pocket depth in the grafted sites compared with the nongrafted sites (P < .001). Moreover, there was a significant difference in the alveolar bone height during the monitoring periods for the grafted sites compared with the nongrafted sites (P < .001). CONCLUSIONS: Grafting of osseous defects distal to mandibular second molars with an anorganic xenograft plus a membrane predictably resulted in a significant reduction in the probing pocket depth, clinical attachment level gain, and bone fill, which suggests that grafting the extraction sites with an anorganic xenograft plus a membrane could prevent periodontal disease in the future.

Composite bone graft for treatment of osseous defects after surgical removal of impacted third and second molars: case report and review of the literature.

The aim of this case report was to evaluate the clinical and radiographic measurements of mandibular first molar bone support after mandibular third and second molar extraction and immediate augmentation of the extraction site with a combined autogenous bone graft with Bio-Oss materials. A pyramidal full-thickness mucoperiosteal flap with 1 distal releasing incision was used for removal of impacted third and second molars. During the procedure, autogenous bone graft was collected with a bone trap and then combined with Bio-Oss materials. The osseous defects distal to first molar and extraction site was filled with the composite bone graft and covered with Bio-Gide membrane. After 1 year, there was a successful defect regression and gain of bone and clinical attachment level. Moreover, there was a reduction of probing pocket depth and gingival inflammation. From the results of this study, it can be concluded that grafting of osseous defects and extraction site with autogenous bone graft combined with Bio-Oss materials will predictably result in a decreased risk of developing a periodontal defect on the distal aspect of mandibular first molar.