Frequency and features of medical emergencies at a teaching dental hospital in Saudi Arabia: a 14-year retrospective observational study.

BACKGROUND: This study aimed to determine the nature, frequency, and characteristics of medical emergencies occurring at the King Abdulaziz University Dental Hospital. MATERIALS AND METHODS: The incident reports of medical emergencies recorded at the King Abdulaziz University Dental Hospital from January 2008 to December 2022 were retrospectively reviewed. The annual/overall incidence of medical emergency events was calculated per 100,000 patients. The following characteristics of the patients/events were evaluated: age, gender, operator, procedure, location, timing of treatment, administration of local anesthesia, past medical history, symptoms, diagnosis, outcome, and disposition. Multivariable logistic regression models were used to investigate the associations of these characteristics with two outcomes: syncope and transfer to the emergency room (ER). RESULTS: The incidence of emergency events was 17.4 per 100,000 patients. Syncope and hypoglycemia were the most common emergencies. Most incidents recovered, with only 13% requiring transfer to the ER. Undergoing no procedure and American Society of Anesthesiologists (ASA) class 2,3 were associated with syncope. Undergoing a general dental procedure, ASA class 2,3, and a diagnosis other than hypoglycemia and syncope were associated with transfer to the ER. CONCLUSIONS: The incidence of medical emergencies was low. Dental practitioners need to remain aware of the contributing factors, such as past medical history and anxiety, but medical emergencies can occur in healthy individuals as well. Preparation of the dental office, training of the personnel, and proper recording of the events are essential components of a well-established medical emergency protocol in dental institutions.

Evaluating the use of role-play simulations in teaching management of medical emergencies in the dental clinic.

BACKGROUND: Practical hands-on training is necessary for clinical competence in managing medical emergencies in the dental setting. Therefore, the King Abdulaziz University Faculty of Dentistry developed a role-play simulation-based clinical module for training clinical years (Years 4, 5, and 6) dental students in medical emergency management between 2016 and 2020. This study aimed to assess the knowledge and skills of years 4, 5, and 6 dental students before and after the completion of the role-play simulation-based medical emergency training module. METHODS: A mandatory four-hour annual training module was designed consisting of a 45-minute lecture on the medical emergency basic action plan and overview, four hands-on stations, and six role-play simulation-based medical emergency stations. A 16-item multiple choice test was used to assess the knowledge of the students before and after the training module every academic year. An objective structured clinical exam (OSCE) on a medical emergency scenario was administered to the students graduating each year. The difference between the pre- and post-module test scores and the one-time OSCE pass/fail rate were analyzed statistically using appropriate tests. RESULTS: A total of 846 students participated in the study between 2017 and 2020: 275 once, 483 twice, 87 thrice, and one participated four times; in total, 1,506 assessments were conducted. Overall, the pre-test and post-test mean scores were 9.4 ± 3.0 and 13.5 ± 1.6, respectively. All students showed significant improvements in the post-test scores compared to the pre-test scores. Year 4 students showed the highest improvement, followed by Year 5 and Year 6. There was a statistically significant association between the pass/fail rate of the OSCE station and the number of times the module was taken. CONCLUSIONS: The significant improvement in the scores of clinical year students in this study supports an annual mandate for all dental students to undergo simulation-based competency training in their clinical years. Teaching institutions are recommended to utilize simulation and hands-on instruction to teach medical emergency management.

Pre-Procedure Blood Sugar Levels in Diabetic and High-Risk Patients Visiting King Abdulaziz University Dental Hospital: The Role of the Dentist in Diabetes Screening.

Aim: Diabetes mellitus (DM) is a widespread problem. Satisfactory control of DM is essential for maintaining oral health and optimizing the outcomes of dental treatment; DM patients with poor glycaemic control have a high risk of dental treatment-related complications. Furthermore, the dentist and dental office can play an important role in DM screening. Therefore, this study aimed at measuring random blood glucose (RBG) levels in patients with established DM or high risk of DM seeking dental treatment at the King Abdulaziz University Dental Hospital to avoid treatment complications and execute an immediate physician referral. Methods and Material: This cross-sectional study included patients presenting to our institution for dental treatment, who were categorized as diabetic (established diagnosis) or at high risk of DM according to the American Diabetes Association criteria. Participants' pre-procedure RBG level was assessed via a glucometer. High-risk participants were classified as per their blood glucose level into two groups (<200 mg/dL and >200 mg/dL), while the diabetic participants were placed into four groups (<140 mg/dL; 140 to <200 mg/dL; 200-300 mg/dL; and >300 mg/dL). Results: This study included 695 patients (361 females and 334 males), of which 354 (52%) had established DM and 341 (48%) were high-risk patients. Around 31% of patients in the high-risk group were potentially diabetic but unaware of it; 46% of the diabetic patients had RBG levels >200 mg/dL. For the high-risk participants, age had a statistically significant association (P-value 0.03) with the RBG level. Conclusion: Pre-procedure RBG measurement in diabetic and high-risk patients undergoing dental treatment is crucial for the prevention of DM-related complications. Dental health-care professionals have a vital role in screening, early detection, and referral of these patients.

Prevalence of patients at risk for developing obstructive sleep apnea based on the STOP-BANG questionnaire at King Abdulaziz University Faculty of Dentistry.

OBJECTIVE: Obstructive sleep apnea (OSA) is a common sleep disorder. Its susceptibility can easily be detected when it is at an early stage as can patients who are at risk of OSA. A simple questionnaire such as STOP-BANG (SB) can facilitate early detection. Our study aims to assess the risk of OSA and evaluate its correlating risk factors in patients attending King Abdulaziz University Faculty of Dentistry (KAUFD), Jeddah, Saudi Arabia, using the SB questionnaire. METHODS: Ethical approval was obtained. A random sample of patients ages 18-80 years, who visited KAUFD between November 2016 and April 2017 were recruited. Three highly trained and calibrated dental interns obtained the following measurements (weight, height, blood pressure, and neck circumference) and administered the questionnaire in a face-to-face interview. RESULTS: A total of 55 patients (62% females) participated in the study with a mean age of 34.6 years and hypertension reported as 16.4%. According to the SB, 31% of patients were found at high risk of OSA. Large neck circumference (40.22[±4.7] cm) and gender (66% males) were found to be significantly correlated with high-risk patients; p < .001. CONCLUSION: Approximately one third of the patients were at high risk of OSA, with men and patients having large neck circumference being significantly more affected. Systolic blood pressure, hypertension, and smoking were found to be high in high-risk patients. However, they were not statistically and significantly different from those patients who were not in high risk. The role of a dentist should be to utilize the questionnaire to detect any patient at risk of OSA and refer them accordingly.

An Unusual Representation of an Odontogenic Cyst Engulfing the Inferior Alveolar Nerve.

This report investigates the growth of an odontogenic cyst around the inferior alveolar nerve (IAN), a crucial vital structure to be approached during oral and maxillofacial surgical procedures. A unique aspect of this case was that the cyst completely engulfed the IAN rather than displacing it and left the patient asymptomatic. Under general anesthesia, complete enucleation of the cyst was performed while the IAN was dissected away. The patient had a temporary neurosensory dysfunction, which they fully recovered from. It is extremely rare for pathological entities to engulf the mandibular canal (MC); however, if the lesion is noninvasive, an excellent prognosis is likely to be expected.

A survey to assess knowledge, practice, and attitude of dentists in the Western region of Saudi Arabia.

OBJECTIVES: To assess knowledge regarding the management of odontogenic infections by dentists in Jeddah, Kingdom of Saudi Arabia. METHODS: In this cross-sectional study, 150 practitioners responded to a 26-item paper-based questionnaire between August and December 2014. The questionnaire evaluated knowledge and current clinical practices in managing odontogenic infections, as well as the attitude towards antibiotic use and resistance in the community. Basic medical knowledge (BMK) and critical knowledge (CK) scores were calculated from the dentists' response to these questions and were compared according to educational level (bachelor and postgraduate degree holders). RESULTS: The mean BMK score was 1.98 ± 0.4 and CK score was 1.89 ± 0.3. Dentists with bachelor's degrees had higher BMK scores than those with a postgraduate degree (p=0.005), but CK was not significantly different (p=0.400). Most dentists (77%) would prescribe antibiotics after a routine dental extraction, and would undertake definitive surgical treatment (49.2%) only after a localized space infection developed. Although 82.2% agreed that routine prescription of antibiotics increases bacterial resistance in the community, 71% believe that prescribing an antibiotic after routine oral surgical procedures prevents odontogenic infections. CONCLUSION: Dentists in Jeddah require further education through lectures and workshops to stay up to date on current concepts in odontogenic infection management.

The validity of three neo-classical facial canons in young adults originating from the Arabian Peninsula.

INTRODUCTION: Understanding facial harmony and proportions is essential for facial reconstructive procedures and orthognathic surgery planning. In the literature, the neoclassical facial canons have been revisited in populations including North American whites and African Americans. The purpose of this study was to establish a baseline for selected facial anthropometric measurements and test the validity of 3 neoclassical facial canons in a cohort of young Saudi adults originating from the Arabian Peninsula. METHODS: The study group consisted of 168 healthy, esthetically pleasing Saudi Arabian dental students originating from the Arabian Peninsula (93 males and 75 females, age 20-24 years). Using a caliper, three neoclassical facial canons were measured; the vertical thirds of the face, the orbital canon (intercanthal distance = eye fissure length), and the orbito-nasal canon (intercanthal distance = nasal width) and analyzed using Student's t-test, general linear modeling, and pairwise comparison of means. RESULTS: The upper, middle, and lower thirds were not equal in measurement to each other (p < 0.0001). Sex dimorphism was observed in the lower facial third and nasal width measurements, with both larger in men (both p < 0.0001). The majority of subjects had longer upper and lower thirds than middle thirds, with 91.4% of males and 88% of females demonstrating a larger lower third than middle third. The most frequent variation in the orbital canon was a wider intercanthal distance than eye fissure length (55.9% of males and 74.7% of females). The most frequent variation in the orbito-nasal canon was a wider nasal width than intercanthal distance (92% of males and 56% of females). CONCLUSIONS: Although these individuals are esthetically pleasing, they do not exhibit equal facial thirds or conform to orbital or orbito-nasal canons. The three neoclassical canons studied could not be validated in young adults originating from the Arabian Peninsula. Thus, the esthetic goals in reconstructive and orthognathic surgery should respect this ethnic variation.

Sodium hypochlorite accident resulting in life-threatening airway obstruction during root canal treatment: a case report.

AIM: This case report describes a serious and life-threatening complication of the use of sodium hypochlorite as an irrigation solution in root canal therapy. SUMMARY: This case report describes a hypochlorite accident that occurred in a healthy 42-year-old female who was undergoing routine root canal therapy for the lower right central incisor (tooth #41). After approximately 1 hour of irrigation with 3% sodium hypochlorite (for a total of 12 cc), the patient complained of severe pain and burning in the lip. The swelling progressed over the next 8 hours to involve the sublingual and submental fascial spaces with elevation of the tongue and resultant upper airway obstruction. The patient was intubated and remained on mechanical ventilation for 3 days. She recovered without any skin necrosis or nerve deficits. KEY LEARNING POINTS: This case report highlights the importance of carefully performing root canal irrigation with sodium hypochlorite to avoid complications. Careful injection without pressure, the use of proper rubber dam isolation, and the use of the endodontic needle are necessary to avoid this type of complication. Although it is a safe root canal irrigation solution, its use may lead to life-threatening complications. Early recognition and management of the untoward effects of sodium hypochlorite are vital for the patient's safety.

The preparedness of private dental offices and polyclinics for medical emergencies. A survey in Western Saudi Arabia.

OBJECTIVES: To assess preparedness for medical emergencies in private dental offices in Jeddah, Kingdom of Saudi Arabia (KSA). METHODS: In this cross-sectional study, a survey was distributed to 70 dental offices and polyclinics in Jeddah, Saudi Arabia between October 2013 and January 2014. The questionnaire gathered information on the prevention of medical emergencies, the preparedness of the office personnel, and availability of emergency drugs and equipment. RESULTS: For prevention, 92% (n=65) of the offices reported that they obtain a thorough medical history prior to treatment; however, only 11% (n=8) obtain vital signs for each visit. Using a preparedness percent score (0 to 100), the mean level of preparedness of the office personnel in all surveyed dental offices was 55.2±20. The availability of emergency drugs was 35±35, and equipment was 19±22. CONCLUSION: We found a deficiency in personnel training, availability of drugs, and emergency equipment in the surveyed dental clinics. More stringent rules and regulations for emergency preparedness must be reinforced to avoid disasters in these clinics.

Predictors of intra-operative blood loss and blood transfusion in orthognathic surgery: a retrospective cohort study in 92 patients.

BACKGROUND: Patients undergoing orthognathic procedures can require blood transfusions. The objectives of this study were to evaluate the predictors of intra-operative blood loss in patients undergoing orthognathic procedures and the transfusion rates and practices of our institution. MATERIALS AND METHODS: This retrospective study included 92 patients who underwent the following four types of orthognathic procedures: Group 1, bimaxillary; Group 2, bimaxillary with bone grafts; Group 3, LeFort I osteotomies; and Group 4, LeFort I osteotomies with bone grafts. The intra-operative blood loss, operative time, age, gender and pre- and post-operative HGB and HCT were assessed. RESULTS: The mean blood loss for all groups was 650 ± 397.8 mL, and there were differences in blood loss between the four groups (p = 0.211). The mean operative time was 5 hours and 32 minutes. There were no differences in intra-operative blood loss between the genders or the BMI categories. The operative time was moderately correlated with the intra-operative blood loss (p < 0.001, r =0.332). Eighteen of the 92 patients (19.5%) received blood transfusions. The mean intra-operative blood loss was higher among the patients who received transfusions (p < 0.001). CONCLUSIONS: The only predictor of intra-operative blood loss was operative time. The observed transfusion rate was higher than those that have been reported for similar procedures; thus, our institution needs to revisit our transfusion policy and use more time-efficient techniques in the operating room.

Role of Fas and Treg cells in fracture healing as characterized in the fas-deficient (lpr) mouse model of lupus.

Previous studies showed that loss of tumor necrosis factor α (TNFα) signaling delayed fracture healing by delaying chondrocyte apoptosis and cartilage resorption. Mechanistic studies showed that TNFα induced Fas expression within chondrocytes; however, the degree to which chondrocyte apoptosis is mediated by TNFα alone or dependent on the induction of Fas is unclear. This question was addressed by assessing fracture healing in Fas-deficient B6.MRL/Fas(lpr) /J mice. Loss of Fas delayed cartilage resorption but also lowered bone fraction in the calluses. The reduced bone fraction was related to elevated rates of coupled bone turnover in the B6.MRL/Fas(lpr) /J calluses, as evidenced by higher osteoclast numbers and increased osteogenesis. Analysis of the apoptotic marker caspase 3 showed fewer positive chondrocytes and osteoclasts in calluses of B6.MRL/Fas(lpr) /J mice. To determine if an active autoimmune state contributed to increased bone turnover, the levels of activated T cells and Treg cells were assessed. B6.MRL/Fas(lpr) /J mice had elevated Treg cells in both spleens and bones of B6.MRL/Fas(lpr) /J but decreased percentage of activated T cells in bone tissues. Fracture led to ∼30% to 60% systemic increase in Treg cells in both wild-type and B6.MRL/Fas(lpr) /J bone tissues during the period of cartilage formation and resorption but either decreased (wild type) or left unchanged (B6.MRL/Fas(lpr) /J) the numbers of activated T cells in bone. These results show that an active autoimmune state is inhibited during the period of cartilage resorption and suggest that iTreg cells play a functional role in this process. These data show that loss of Fas activity specifically in chondrocytes prolonged the life span of chondrocytes and that Fas synergized with TNFα signaling to mediate chondrocyte apoptosis. Conversely, loss of Fas systemically led to increased osteoclast numbers during later periods of fracture healing and increased osteogenesis. These findings suggest that retention of viable chondrocytes locally inhibits osteoclast activity or matrix proteolysis during cartilage resorption.

Surgical Orthodontic Treatment of Severe Skeletal Class II.

This paper describes an adult Saudi male patient who presented with a severe skeletal class II deformity. The case was managed with a combination of presurgical orthodontic treatment followed by a double jaw orthognathic surgery and then another phase of orthodontic treatment for final occlusal detailing. Extraction of the four first premolars was done during the presurgical orthodontic phase of treatment to decompensate upper and lower incisors and to give room for surgical setback of the maxillary anterior segment. Double jaw surgery was performed: bilateral sagittal split ramus osteotomy for 8 mm mandibular advancement combined with three-piece Le Fort I maxillary osteotomy, 6 mm setback of the anterior segment, 8 mm impaction of the maxilla, and 5 mm advancement genioplasty. Although the anteroposterior discrepancy and the facial convexity were so severe, highly acceptable results were obtained, both esthetically as well as occlusally.

Variation of pediatric and adolescents head and neck pathology in the city of Jeddah: A retrospective analysis over 10 years.

This study was conducted to present a comprehensive view of the most common head and neck pathologies among the pediatric and adolescent population of the city of Jeddah, Saudi Arabia. Data were collected from the oral and maxillofacial surgery (OMFS) records at King Abdulaziz University Hospital and King Fahad Hospital Jeddah (KFHJ) from the period 1998 to 2009. All patients who were 18 years of age and younger were included in the study. Identified lesions were classified into four categories: cystic, neoplastic, vascular and fibro-osseous. Age and sex distribution of the lesions were also calculated. A total of 155 patients were included in this study. Of all the lesions, 143 (92.26%) were benign and 12 (7.74%) were malignant; 63 (40.65%) were cysts; 48 (30.97%) were neoplasms; 23 (14.84%) were vascular and 21 (13.55%) were fibro-osseous tumors. The most common lesions were hemangioma (20 cases; 12.9%) followed by retention cyst (19 cases; 12.26%) and dentigerous cyst (15 cases; 9.68%). The most common benign odontogenic neoplasm was odontoma (7 cases; 4.52%), of which central giant cell granuloma (6 cases; 3.87%) was the most frequent benign nonodontogenic tumor and lymphoma (6 cases; 3.87%) was the most common malignant one. Although this study might benefit clinicians in guiding them through differential diagnosis of pediatric and adolescent head and neck pathology in reference to their sex and age groups, governmental efforts are badly needed to establish a Saudi childhood pathology registry.

Enhanced chondrogenesis and Wnt signaling in PTH-treated fractures.

UNLABELLED: Studies have shown that systemic PTH treatment enhanced the rate of bone repair in rodent models. However, the mechanisms through which PTH affects bone repair have not been elucidated. In these studies we show that PTH primarily enhanced the earliest stages of endochondral bone repair by increasing chondrocyte recruitment and rate of differentiation. In coordination with these cellular events, we observed an increased level of canonical Wnt-signaling in PTH-treated bones at multiple time-points across the time-course of fracture repair, supporting the conclusion that PTH responses are at least in part mediated through Wnt signaling. INTRODUCTION: Since FDA approval of PTH [PTH(1-34); Forteo] as a treatment for osteoporosis, there has been interest in its use in other musculoskeletal conditions. Fracture repair is one area in which PTH may have a significant clinical impact. Multiple animal studies have shown that systemic PTH treatment of healing fractures increased both callus volume and return of mechanical competence in models of fracture healing. Whereas the potential for PTH has been established, the mechanism(s) by which PTH produces these effects remain elusive. MATERIALS AND METHODS: Closed femoral fractures were generated in 8-wk-old male C57Bl/6 mice followed by daily systemic injections of either saline (control) or 30 microg/kg PTH(1-34) for 14 days after fracture. Bones were harvested at days 2, 3, 5, 7, 10, 14, 21, and 28 after fracture and analyzed at the tissue level by radiography and histomorphometry and at the molecular and biochemical levels level by RNase protection assay (RPA), real-time PCR, and Western blot analysis. RESULTS: Quantitative muCT analysis showed that PTH treatment induced a larger callus cross-sectional area, length, and total volume compared with controls. Molecular analysis of the expression of extracellular matrix genes associated with chondrogenesis and osteogenesis showed that PTH treated fractures displayed a 3-fold greater increase in chondrogenesis relative to osteogenesis over the course of the repair process. In addition, chondrocyte hypertrophy occurred earlier in the PTH-treated callus tissues. Analysis of the expression of potential mediators of PTH actions showed that PTH treatment significantly induced the expression of Wnts 4, 5a, 5b, and 10b and increased levels of unphosphorylated, nuclear localized beta-catenin protein, a central feature of canonical Wnt signaling. CONCLUSIONS: These results showed that the PTH-mediated enhancement of fracture repair is primarily associated with an amplification of chondrocyte recruitment and maturation in the early fracture callus. Associated with these cellular effects, we observed an increase in canonical Wnt signaling supporting the conclusion that PTH effects on bone repair are mediated at least in part through the activation of Wnt-signaling pathways.

Diminished bone formation during diabetic fracture healing is related to the premature resorption of cartilage associated with increased osteoclast activity.

UNLABELLED: Histological and molecular analysis of fracture healing in normal and diabetic animals showed significantly enhanced removal of cartilage in diabetic animals. Increased cartilage turnover was associated with elevated osteoclast numbers, a higher expression of genes that promote osteoclastogenesis, and diminished primary bone formation. INTRODUCTION: Diminished bone formation, an increased incidence of nonunions, and delayed fracture healing have been observed in animal models and in patients with diabetes. Fracture healing is characterized by the formation of a stabilizing callus in which cartilage is formed and then resorbed and replaced by bone. To gain insight into how diabetes affects fracture healing, studies were carried out focusing on the impact of diabetes on the transition from cartilage to bone. MATERIALS AND METHODS: A low-dose treatment protocol of streptozotocin in CD-1 mice was used to induce a type 1 diabetic condition. After mice were hyperglycemic for 3 weeks, controlled closed simple transverse fractures of the tibia were induced and fixed by intramedullary pins. Histomorphometric analysis of the tibias obtained 12, 16, and 22 days after fracture was performed across the fracture callus at 0.5 mm proximal and distal increments using computer-assisted image analysis. Another group of 16-day samples were examined by microCT. RNA was isolated from a separate set of animals, and the expression of genes that reflect the formation and removal of cartilage and bone was measured by real-time PCR. RESULTS: Molecular analysis of collagen types II and X mRNA expression showed that cartilage formation was the same during the initial period of callus formation. Histomorphometric analysis of day 12 fracture calluses showed that callus size and cartilage area were also similar in normoglycemic and diabetic mice. In contrast, on day 16, callus size, cartilage tissue, and new bone area were 2.0-, 4.4-, and 1.5-fold larger, respectively, in the normoglycemic compared with the diabetic group (p < 0.05). Analysis of microCT images indicated that the bone volume in the normoglycemic animals was 38% larger than in diabetic animals. There were 78% more osteoclasts in the diabetic group compared with the normoglycemic group (p < 0.05) on day 16, consistent with the reduction in cartilage. Real-time PCR showed significantly elevated levels of mRNA expression for TNF-alpha, macrophage-colony stimulating factor, RANKL, and vascular endothelial growth factor-A in the diabetic group. Similarly, the mRNA encoding ADAMTS 4 and 5, major aggrecanases that degrade cartilage, was also elevated in diabetic animals. CONCLUSIONS: These results suggest that impaired fracture healing in diabetes is characterized by increased rates of cartilage resorption. This premature loss of cartilage leads to a reduction in callus size and contributes to decreased bone formation and mechanical strength frequently reported in diabetic fracture healing.

Analysis of fracture healing by large-scale transcriptional profile identified temporal relationships between metalloproteinase and ADAMTS mRNA expression.

The aim of this study was to validate the use of transcriptional profiling as a means of characterizing the complex interactions of the thousands of genes that are expressed during fracture healing. Standard mid-diaphyseal tibia fractures were generated in C57/B6 murine tibiae and the transcriptional expression of approximately 13,000 genes was assessed. Three time points after fracture were assessed: day 3, representative of the inflammatory phase; day 10, representative of the peak of cartilage formation; and day 21, representative of the period of primary bone formation and coupled remodeling. A self-organizing mapping approach of the data revealed the temporal relationships between the expression of mRNAs for extracellular matrix proteins and the proteases that degrade the proteoglycan and collagenous matrices. A broad group of extracellular matrix protein mRNAs representative of basement membranes, blood vessels and cartilage all showed elevated expression over the first 21 days of fracture healing. The sorting of the data identified an orderly temporal expression of the metalloproteinases and ADAMTS during the progression of fracture healing with (MMP2/MMP14/TIMP2) and ADAMTS4 and 15 preceding the expression of (MMP9/MMP13). Based on their patterns of expression, relative to the known activities of the encoded proteolytic enzymes, our results suggest that the dissolution of cartilage protoeglycans proceeds before the underlying collagenous components of the matrix are removed. The exclusion of several mRNAs that are normally expressed by osteoclasts in the profiles of mRNAs from days 3 and 10 suggests that osteoclastic activity was largely absent during the early periods of cartilage tissue formation and that proteoglycan and specific collagenase activities, precedes or is prerequisite to later osteoclast infiltration into the remodeling tissues.

Mandibular distraction osteogenesis: a rabbit model using a novel experimental design.

PURPOSE: Distraction osteogenesis (DO) is a surgical procedure that targets bone regeneration and elongation, currently used in the treatment of many craniofacial deformities. The quest for optimization of DO clinical parameters has led to the development of a variety of animal models. Our study aims to establish a rabbit animal model of mandibular DO, in which the control osteotomy and distraction device are placed on the opposite hemimandible from the one being distracted, within the same animal host. Furthermore, we propose to histologically characterize the different stages or distraction and consolidation in the same animal model. MATERIALS AND METHODS: Twenty-five rabbits underwent mandibular osteotomies and bilateral placement of distraction devices. After a latency of 3 days, the distraction device was activated on one side of each animal at a rate of 0.5 mm/12 hours for 7 days, while the other side remained inactive (control). This was followed by a consolidation period of 14 days. Five animals per time-point were killed on days 3, 7, 10, 17, and 24. RESULTS: Gross tissue analysis showed a 7-mm callus formation at the distracted side and a well-healed osteotomy in the non-distracted side. Clinically, a unilateral Class III malocclusion occurred in the distracted side. Histology at each time-point shows new bone formation and orientation of the bony spicules along the axis of the mechanical strain. CONCLUSIONS: We have established and characterized an animal model of mandibular DO that outlines valid biologic controls and provides thorough monitoring of the DO process.

Technique for in-office cranial bone harvesting.

PURPOSE: This is a report of a technique of cranial bone harvesting suitable for the outpatient setting. MATERIALS AND METHODS: Bone scrapers are used for the harvesting of cranial bone shavings with the patient under intravenous sedation or general anesthesia. RESULTS: Graft volumes larger than that usually obtainable from intraoral sites and the tibia have been harvested utilizing this technique. In a series of 8 first patients, the largest volume of bone obtained was 14 cc with no complications related to the donor sites. These cases include the following types of pre-implant reconstructive procedures: large unilateral sinus grafting, bilateral sinus grafting/guided-bone regeneration of an entire alveolar ridge, inlay grafting of the alveolus, inlay grafting in association with distraction osteogenesis, subnasal grafting, alveolar cleft grafting, closure of large oroantral defects combined with sinus grafting, and grafting of an grossly atrophic mandible with simultaneous placement of dental implants via the submental approach. CONCLUSION: This is a safe bone harvesting technique providing an alternative source of autogenous bone graft.