A sheep cadaver model for demonstration and training periodontal surgical methods

EXERCISE IMPROVES ALVEOLAR BONE LOSS AND THE INFLAMMATORY PROFILE OF PERIODONTAL DISEASE

ABSTRACT Periodontal disease (PD) is an inflammatory oral disease and alveolar bone loss is the most important sign of PD. However, the effects of exercise on inflammatory factors and alveolar bone loss in individuals with PD have been little studied. This meta-analysis assesses the effect of physical exercise on alveolar bone loss (ABL) and the inflammatory profile of PD in animal models. Relevant studies published through July 2020 in PubMed, Medline, Embase and Web of Science were searched after developing a PICOS statement. Quality assessment and risk of bias were analyzed according to the SYRCLE protocol. A total of 52 references were retrieved, 4 of which were considered eligible for inclusion. A total of thirty-four male Wistar rats from the included studies were evaluated for alveolar bone loss and assessed for inflammatory profile. The results indicated that physical exercise could reduce alveolar bone loss (95% CI -2.85 to -0.82, p = 0.002) and the pro-inflammatory tumor necrosis factor–α (TNF-α) in serum or gingival tissue (95% CI -0.45 to -0.24, p < 0.00001). Inversely, exercise increased anti-inflammatory interleukin–10 (IL-10) in serum or gingival tissue (95% CI 0.28 to 0.69, p < 0.00001). However, one study reported a negative result in the expression of TNF-α and IL-10. Current evidence indicates that physical exercise contributes to ameliorate PD by reducing alveolar bone loss and inflammation in animal PD models, which suggests that moderate exercise can be implemented in clinical practice to maintain periodontal health. Level of Evidence I; Systematic Review and Meta-analysis

Assessment of a developed pig cadaver model for teaching crown lengthening surgical procedures

Background

Information regarding using a pig cadaver model for teaching purposes in dentistry is limited, especially for periodontal surgery procedures. The aim of this study was to assess the feasibility and efficacy of teaching crown lengthening surgical procedures using a prepared pig cadaver model.

Methods

Mandibles of slaughtered pigs with subgingival crown fracture defects on two premolars and two molars on each side were prepared as periodontal surgery teaching cases. A resident group (n = 20) and an instructor group (n = 18) participated in assessing the efficacy of the model by completing questionnaires before and after training sessions. Data was either assessed descriptively or analyzed statistically with Wilcoxon signed-rank test with the significance level at α = 0.05.

Results

Results revealed that all the knowledge points showed statistically significant improvements (p < 0.05) except for the procedure to determine the quantity of bone removal during osteotomy procedures. Most residents rated the efficacy of the model obtained with 9.0 out of 10 scale. The data of effectiveness of the pig cadaver model from the instructor group ranged from 7.4 ± 1.4 to 9.0 ± 1.0.

Conclusion

Results of this study support feasibility in using prepared pig cadaver models to teach crown lengthening surgical procedures to postgraduates.

The Usefulness of Saturated Salt Solution Embalming Method for Oral Surgical Skills Training: A New Cadaveric Training Model for Bone Harvesting

The purpose of this study was to assess the usefulness of saturated salt solution-embalmed cadavers for oral surgical skills training related to bone graft harvesting. Two half-day surgical skills training workshops were held at the Tokyo Medical University utilizing eight cadavers embalmed with the saturated salt solution. A total of 22 participants including oral surgeons, residents, and dentists attended the workshop. Surgical training consisted of six procedures related to intraoral and extraoral bone harvesting. The participants were surveyed to assess self-confidence levels for each surgical procedure before and after completion of each workshop. The Wilcoxon signed-rank test was used to compare the differences between each median score before and after the workshop. There were statistically significant increases in the self-assessed confidence scores in bone harvesting procedures for the zygomatic bone (P = 0.003), maxillary tuberosity (P = 0.002), and other sites (P < 0.001). The anatomical features of saturated salt solution-embalmed cadavers were also examined. The textures of the oral mucosa and skin were similar to those of living individuals. The structure of bone tissues was well-preserved and the hardness was realistic. Consequently, all procedures were performed with sufficient realism. The saturated salt solution method has a relatively low cost of preparation and storage, and almost no odor. The authors suggest that saturated salt solution-embalmed cadavers could provide a new model for oral surgical skills training in bone harvesting.

Assessment of a Novel Standardized Training System for Mandibular Contour Surgeries

Importance

Mandibular contour surgeries (MCS) involving reduction gonioplasty and genioplasty are rewarding for patients with square faces; however, the procedure has inherently difficult clinician learning curves and unpredictable skill acquisitions. To our knowledge, there has been no effective, validated training model that might improve training and surgical outcomes for MCS.

Objective

To establish and evaluate a standardized intraoral MCS training system.

Design, Setting, and Participants

Intraoral MCS training models were constructed by 3-dimensional (3D) skull models covered with elastic head cloths. From April 2016 to April 2018, 90 consecutive MCS patients (30 per group) and 15 craniofacial surgery fellow physicians (5 per group) were enrolled in the prospective observational study. They were randomly divided into intervention groups (A and B) and a control group (C). Intervention groups A and B completed 5 training sessions on the intraoral MCS training models before each clinical case. Group A performed both the model training sessions and clinical surgeries with surgical templates. Control group C had no extra training before clinical surgeries. All groups completed clinical surgery under supervision on 6 patients. The duration of follow-up was at least 3 months postoperatively.

Interventions

Intraoral MCS training models were provided to intervention groups (A and B) before clinical surgeries. Surgical templates were provided to intervention group A both in training sessions and clinical surgeries.

Main Outcomes and Measures

The completion time, surgical accuracy, learning curves, operating confidence, surgical skill, and outcome satisfaction of each procedure were recorded and analyzed with paired t test and 1-way analysis of variance test by blinded observers.

Results

All 90 patients (14 men, 76 women; mean [SD] age, 26 [5] years) were satisfied with their postoperative mandible contours. The intervention groups (A and B), especially the group with surgical templates (A) showed improvements in clinical surgery time (mean [SD], group A 147.2 [24.71] min; group B, 184.47 [16.28] min; group C, 219.3 [35.3] min; P = .001), surgical accuracy (mean [SD], group A, 0.68 [0.22] mm; group B, 1.22 [0.38] mm; group C, 1.88 [0.54] mm; P < .001), learning curves, and operators' confidence and surgical skill.

Conclusions and Relevance

The intraoral MCS training model was effective and practical. The optimal intraoral MCS training system included intraoral MCS training models and surgical templates. The system significantly decreased clinical surgery time, improved surgical accuracy, shortened the learning curve, boosted operators' confidence, and was associated with better acquisition of surgical skills.

Level of Evidence

NA.

Comparison of in situ cone beam computed tomography scan data with ex vivo optical scan data in the measurement of root surface area

OBJECTIVE

The aim of this study was to compare root surface area (RSA) measurements of single-root teeth in a sheep mandible based on cone beam computed tomography (CBCT) with measurements made with an optical scanner.

STUDY DESIGN

Eight anterior teeth of a sheep cadaver mandible were scanned in situ by using CBCT with 3 different exposure parameters, followed by treatment with smoothing software. The teeth were then extracted and scanned individually with an optical scanner. Three-dimensional digital models of the teeth were reconstructed on the basis of CBCT and optical scanner data. RSA data were calculated, and an equivalence test was used to statistically compare the measurements with significance of difference established at α = 0.05.

RESULTS

The means of the differences between RSA measurements from CBCT and optical scanning ranged from 0.33% to 3.01%. There were no statistically significant differences between the 2 methods. The smoothing parameters for good fitness of the linear regression were determined to be 0.8 for the smooth factor, 8 for iterations, and 0 for compensate shrinkage.

CONCLUSIONS

The proposed CBCT technique to measure RSA is feasible. RSA data obtained from CBCT in situ are as accurate as optical scanner measurements ex vivo.

An Effective Simulator for Intraoral Facial Skeletal Contour Surgeries

BACKGROUND

In East Asia, intraoral facial skeletal contour surgeries (intraoral FSCSs), including reduction gonioplasty, reduction malarplasty, and genioplasty, have become increasingly popular. Nonetheless, intraoral FSCSs are technically difficult and have a steep learning curve. An effective simulator could be beneficial for intraoral FSCS training. However, there is no intraoral FSCS simulator available. We introduced an intraoral FSCS simulator and assessed its effectiveness.

METHODS

An intraoral FSCS simulator was established by covering a 3-dimensional printed skull with elastic cloth. Twenty residents were enrolled and randomly divided into experimental group A and control group B. Group A performed the intraoral FSCS on the simulator for 3 times. Group B performed the intraoral FSCS on skull model for 3 times. The intraoral FSCS simulator and trainees' performance were evaluated by a trainee-reported questionnaire before and after training, the surgical outcomes were graded by 3 senior attending physicians. All questions and the surgical outcome were scored based on a 5-point Likert scale (1 = very poor, 5 = very good). The surgical times were recorded.

RESULTS

The intraoral FSCS simulator (4.13 ± 0.64) simulated the surgical reality significantly better than the skull (2.6 ± 0.63). In intraoral FSCS simulator training, the restriction and compliance of the facial soft tissue were vividly mimicked (4.4 ± 0.51); the intraoral approach was vividly mimicked (4.07 ± 0.59). The intraoral FSCS simulator is significantly superior to the skull in improving participants' confidence in performing intraoral FSCS, power system control, and intraoral approach adoption (<0.001). The average surgical outcome score was 3.11 ± 0.45 in group A and 3.91 ± 0.24 in group B. The average surgical time was 177.78 ± 28.38 minutes in group A and 65.26 ± 15.38 minutes in group B.

CONCLUSIONS

We developed the first intraoral FSCS simulator and proved its effectiveness preliminarily. Randomized controlled study with clinical cases is needed to further test its effectiveness.

Detection of simulated periodontal defects using cone-beam CT and digital intraoral radiography

OBJECTIVES:

This study sought to assess the diagnostic value of CBCT and digital intraoral radiography for the detection of periodontal defects in the sheep mandible.

METHODS:

In this in vitro study, 80 periodontal defects including Grades I, II and III furcation involvements, one-, two-, three-wall and trough-like infrabony defects, fenestration and dehiscence were artificially created in the sheep mandible by burr. Intraoral digital radiographs using photostimulable phosphor plates and CBCT scans were obtained. Three periodontists evaluated the images for the presence and type of defects. The results were compared with the gold standard (photographs of the created defects).

RESULTS:

CBCT scans were significantly superior to digital radiographs for the detection of Grade I furcation involvements, three-wall defects, fenestrations and dehiscence (p < 0.05). No significant difference was noted between CBCT and digital radiography for the detection of Grades II and III furcation involvements, one-wall, two-wall and trough-like defects (p-value > 0.05).

CONCLUSIONS:

CBCT was superior to digital intraoral radiography for the detection of Grade I furcation involvements, three-wall defects, dehiscence and fenestrations.

Lamb ex vivo model for training in maxillary sinus floor elevation surgery: a comparative study with human standards

BACKGROUND

Many models have been suggested for surgical training in sinus floor elevation (SFE), but information on key features that provide feedback to the trainee is scarce. The aim of this study is to compare the thickness of the lateral wall of the maxillary sinus (TLWMS) and the thickness of the Schneiderian membrane (TSM) between an animal model and the human standard.

METHODS

The observational study used 20 fresh lamb heads. Cone-beam computed tomography (CT) was performed for recording the following: TLWMS, sinus lateral floor width, distance from the lateral border of the anteroposterior bone crest to the sinus wall, and height of lateral maxillary sinus. Thirty human radiologic exploration cone-beam CTs were used for comparisons. The sinus membrane thickness was measured at three points per section and compared to those of 10 formalin-preserved human membranes.

RESULTS

TLWMS in the animal model scored 2.25 ± 0.3 mm and was thicker than that of humans with subsinusal edentulism (Xi - Xj = 0.3; 95% confidence interval = 0.1 to 0.4), although this difference was not considered clinically relevant. The average thickness of the sinus membrane was 485.5 ± 137.1 μm with no significant differences between sides (P = 0.12) or between the thickness of human and lamb Schneiderian membranes.

CONCLUSIONS

The model based on lambs is potentially useful for training in SFE techniques because of the similarities in the TLWMS and particularly the TSM. Additional studies are needed to validate this model within a teaching environment.

Utilization and dissection for endoscopic sinus surgery training in the residency program

OBJECTIVE

To develop an animal cadaver model that would allow residents to learn functional endoscopic sinus surgery as a complementary model.

STUDY DESIGN

Prospective experimental study.

PATIENTS AND METHODS

Two of our first-year residents were included in the study, and each operated on 5 sheep noses. All the routine steps of endoscopic sinus surgery were performed, except for sphenoidotomy, and their success and complication scores were recorded. The residents' performance for maxillary antrostomy, ethmoidectomy, and frontal sinusotomy in sheep cadaver noses were evaluated by the authors. Predissection and postdissection computer tomography assessed the completeness of dissection. Images were analyzed for maxillary antrostomy, frontal sinusotomy, residual ethmoid cells and partitions, and residual frontal recess cells. The first and last 5 sides of residents were analyzed together as the first 10 sides (group 1) and last 10 sides (group 2).

RESULTS

Group 2 had significantly better outcomes for frontal sinusotomy and ethmoidectomy (P = 0.011 and P = 0.003, respectively). The mean duration of procedures for group 1 was 15.7 minutes and that for group 2 was 10.3 minutes (P = 0.000). The difference was not significant between the 2 groups when comparing the success rates of maxillary antrostomy and the complication rates (P > 0.05).

CONCLUSIONS

The nasal cavity of the sheep is anatomically similar to the human nasal cavity, and the model using sheep cadaver for endoscopic sinus surgery training is a cost-effective and useful model for the first step of the learning curve.

Thiel embalming technique: a valuable method for teaching oral surgery and implantology

BACKGROUND

Because of its high requirements on surgical experience and the need of complete understanding of the anatomy, oral surgery and especially implantology belong to the most demanding procedures in dentistry. Therefore, hands-on courses for oral surgery and implantology are considered a prerequisite to prepare for clinical practice. To achieve teaching conditions as realistic as possible, we used a novel human cadaver embalming method enabling tissue dissection comparable with the living body.

METHODS

Thirty cadavers which were offered by the Institute of Anatomy for the purpose of running oral surgery and implantology courses were embalmed in the technique described by Thiel. On each cadaver, dissection of soft and hard tissue and implantological procedures were performed according to a structured protocol by each course participant. The conservation of fine anatomical structures and the suitability of the embalmed tissue for dissecting, drilling, and suturing were observed and photographically documented.

RESULTS

By means of the Thiel embalming technique, oral surgery and implantological procedures could be performed under realistic conditions similar to the living body. Due to the conservation procedure, preparations could be carried out without any time limit, always maintaining the same high quality of the tissue. The maxillary sinus membrane, mucosa, bone, and nerves could be exposed and allowed dissecting, drilling, and suturing even after weeks like fresh specimens.

CONCLUSION

The Thiel embalming method is a unique technique which is ideally suited to practice and teach oral surgery and implantology on human material.

Assessment of knowledge and competencies related to implant dentistry in undergraduate and postgraduate university education

Learning in academic settings is strongly related to the way the students are tested or examined. Assessment therefore must be integrated in the curriculum design, coordinated and should reflect the learning outcomes of the education. Assessment within the field of implant dentistry must fulfil four major objectives: complete and direct the learning process with feedback (formative), ensure that students are adequately prepared (summative), assess attitudes and skills such as critical thinking, reflection and self-assessment ability, and supply continuous feedback to teachers on curricular content and impact. Different assessment methods should be used to assess different levels of competencies throughout the curriculum. Various forms of written or oral assessment methodologies are applicable at earlier stages in the curriculum. At intermediate levels, interactive assessment methods, such as patient simulations (paper based or virtual) and more could encourage the necessary synthesis of several disciplines and aspects of the theoretical knowledge. At higher levels of competence, documentation of clinical proficiency by means of reflective portfolios and diaries is an appropriate assessment method with both formative and summative potential. The highest level of competence requires performance assessment using structured, objective, clinical criteria. The group strongly encourages the use of reflective forms of assessment methods which engage the students in a process of self-appraisal, identification of individual learning needs and self-directed learning. The ultimate goal of this would be to allow the student to develop a lifelong learning attitude.