Jurjen Schortinghuis

Microradiography to evaluate bone growth into a rat mandibular defect

Microradiography has been evaluated to measure bone healing into a 5.0mm outer diameter mandibular defect in the rat. This method provides high-resolution radiographs of the defects that can be used for an accurate measurement of bone defect healing. In 12 rats, the defect widths of 42-day-old mandibular defects have been measured both using microradiographs and histological sections. The defect width+/-S.D. measured 3.42+/-0.98 mm microradiographically and 3.47+/-1.11 mm histologically. Both methods were accurate in determining defect widths but microradiography has the advantage over histology that an image is obtained from the entire defect, making it possible to measure areas of bone growth.

Vivosorb®, Bio-Gide®, and Gore-Tex® as barrier membranes in rat mandibular defects: an evaluation by microradiography and micro-CT

OBJECTIVES The objectives of this study were to determine whether a new degradable synthetic barrier membrane (Vivosorb) composed of poly(dl-lactide-epsilon-caprolactone) (PDLLCL) can be useful in implant dentistry and to compare it with collagen and expanded polytetrafluoroethylene (ePTFE) membranes. MATERIAL AND METHODS In 192 male Sprague-Dawley rats, a standardized 5 mm circular defect was created through the right angle of the mandible. New bone formation was evaluated by post-mortem microradiography and micro-CT (muCT) imaging. Four groups (control, PDLLCL, collagen, ePTFE) were evaluated at three time intervals (2, 4, and 12 weeks). In the membrane groups the defects were covered; in the control group the defects were left uncovered. Data were analysed using a multiple regression model. RESULTS New bone formation could be detected by post-mortem microradiography in 130 samples and by muCT imaging in 112 samples. Bone formation was progressive in 12 weeks, when the mandibular defect was covered with a membrane. Overall, more bone formation was observed underneath the collagen and ePTFE membranes than the PDLLCL membranes. CONCLUSIONS In contrast to uncovered mandibular defects, substantial bone healing was observed in defects covered with a PDLLCL membrane. However, bone formation in PDLLCL-covered defects tended to be less than in the defects covered with collagen or ePTFE. The high variation in the PDLLCL samples at 12 weeks may be caused by the moderate adherence of this membrane to bone compared with collagen. These results indicate that further study is needed to optimize the properties of PDLLCL membranes.

Applicability of equine hydroxyapatite collagen (eHAC) bone blocks for lateral augmentation of the alveolar crest. A histological and histomorphometric analysis in rats

This study assessed the mechanical characteristics, biocompatibility and osteoconductive properties of an equine hydroxyapatite collagen (eHAC) bone block when applied as a bone substitute for lateral augmentation of rat mandible. 96 rats underwent lateral augmentation of the mandible, using two substitute bone blocks (eHAC or Bio-Oss spongiosa) or autologous bone grafts. Signs of inflammation, amount of bone formation and ingrowth of bone into the bone blocks were assessed at 1 and 3 months. eHAC blocks were mechanically rigid and could be fixed firmly and easily. Bio-Oss spongiosa blocks were brittle and fixation was difficult. eHAC and Bio-Oss spongiosa blocks were biocompatible and induced few or no signs of inflammation. Inflammation prevalence between the groups was not statistically different. Bone formation and bone growth into the blocks was significantly higher in eHAC than Bio-Oss spongiosa blocks, but lower than in autologous bone grafts (after 1 and 3 months). Regression analysis showed that the autologous bone graft predicted new bone formation at both time points. The eHAC block was only a predictor at 1 month; a trend was found at 3 months. The application of biodegradable membranes was not related to more bone ingrowth.

Vivosorb® as a barrier membrane in rat mandibular defects. An evaluation with transversal microradiography

Vivosorb is a new degradable membrane composed of poly(DL-lactide-epsilon-caprolactone) (PDLLCL). The aim of this study was to appraise its performance in guided bone regeneration procedures. In 192 rats a 5.0 mm defect was drilled in the mandibular angle. The defects were covered with a membrane (PDLLCL, collagen, or expanded polytetrafluoroethylene (ePTFE)) or left uncovered (control). Defect closure, mineralization and thickness of the new bone were assessed by means of transversal microradiography at three different time intervals (2, 4 and 12 weeks). The data were analysed using multiple regression analyses. The regression analyses showed significant effect modification between time and collagen and time and ePTFE for mineralization of the newly formed bone. For defect closure and bone thickness all membrane-treated groups showed effect modification between time and membrane; these effects were more significant and larger in the collagen and ePTFE groups. In the non-treated controls no effect modification was observed. The membrane groups showed significantly better results than the control groups. The ePTFE and collagen membranes performed equally well and better than the PDLLCL membrane during this experiment. It was concluded that a PDLLCL membrane is not suitable for clinical application in its current form.

Retention of lipiodol after parotid gland sialography

There is limited information about the retention of lipiodol in the parotid gland after parotid gland sialography. This study assesses the prevalence of lipiodol retention after parotid sialography and determines if retention of lipiodol is related to the sialography technique or the underlying salivary gland pathology. Using the electronic hospital database (1996-2006), 66 out of 565 patients were identified who had additional maxillofacial radiographic examinations after the initial sialography. Additional radiographs up to October 2007 were included; these were orthopantomographic radiographs in all cases. In 28 patients (42%) signs of lipiodol retention were observed (mean radiographic follow-up: 15+/-13 months). Retention was characterized by small radiopaque spots in the periphery of the gland. Lipiodol retention was predominantly associated with a fausse route (n=8) or the presence of salivary gland disease (sialectasia; n=17). In 9 patients with signs of lipiodol retention, a series of radiographs was available. Lipiodol radiodensities decreased in size during 28 months, and could disappear gradually (follow-up 14-57 months). Despite the high frequency of retention of small depots of lipiodol for years after sialography in patients subjected to additional radiographic examinations, no clinically adverse effects were observed.

Donor site morbidity of anterior iliac crest and calvarium bone grafts: A comparative case-control study

PURPOSE Notwithstanding its donor site morbidity, autogenous bone graft harvesting is still considered the gold standard for cases of extreme resorption of the alveolar ridge. The aim of this study was to assess donor site morbidity of calvarium and anterior iliac crest harvesting. MATERIAL AND METHODS A total of 27 edentulous patients who had undergone calvarial bone harvesting were matched with 27 edentulous patients in which anterior iliac crest bone was harvested. All patients had been treated between March 2011 and December 2013. Patients were matched according to age, sex, and duration of follow-up. Donor site morbidity was assessed by medical records, patient questionnaires, and physical examination. Patients were recalled to assess persisting morbidity of the harvesting procedure. RESULTS Exposure of the dura occurred in three patients in the calvarial group. Postoperative pain (based on a visual analog scale) after harvesting was significantly higher in the anterior iliac crest group. Scars were significantly longer and contours deficits were significantly more prominent after calvarial harvesting, although not bothersome to the patients. Long-term pain was negligible in both groups, and satisfaction with the procedure did not differ. CONCLUSION Both harvesting techniques were accompanied by low long-term donor site morbidity and high patient satisfaction.

Changes in heart rate during third molar surgery.

Anxiety is an undesirable psychological phenomenon. Patients are usually anxious when subjected to third molar surgery, but the pattern of anxiety is unknown. The aim of this study was to assess the intensity and course of anxiety during third molar surgery. This study included 48 consecutive patients (mean age 25±6 years) who had a third molar removed surgically under local anaesthesia. The heart rate was monitored continuously during treatment as a measure of anxiety. Preoperative anxiety was scored with the Modified Dental Anxiety Scale. Each patients anxiety level was assessed when in the waiting room, sitting down in the dental chair, during the application of local anaesthesia, application of surgical drapes, time-out procedure, incision, alveolotomy, removal of the third molar, and suturing, and at the end of the procedure. The lowest heart rates were recorded in the waiting room, in the dental chair, during anaesthesia, when applying surgical drapes, during suturing, and at the end of the procedure. The highest values were obtained during the time-out procedure, incision, and alveolotomy (P<0.005). In conclusion, the intensity and course of anxiety has a specific pattern during third molar surgery, with the lowest levels of anxiety prior to surgery and directly postoperative and the highest during the time-out procedure and the actual surgery.

Hyperbaric Oxygen Therapy for Wound Dehiscence After Intraoral Bone Grafting in the Nonirradiated Patient: A Case Series

PURPOSE In maxillofacial surgery, hyperbaric oxygen treatment is used almost exclusively as adjunctive therapy for osteoradionecrosis of the mandible in irradiated patients. It also is used to prevent the occurrence of osteoradionecrosis in the irradiated patient when dental surgery is indicated. Theoretically, hyperbaric oxygen therapy should benefit the nonirradiated patient in maxillofacial surgery (eg, patients with persistent intraoral wound dehiscences after bone grafting). MATERIALS AND METHODS Six nonirradiated patients underwent hyperbaric oxygen therapy because of compromised wound healing after intraoral bone grafting of the maxilla as a preimplant procedure. All patients were treated 7 to 26 times with hyperbaric oxygen therapy at 2.5 ATA. RESULTS All patients healed uneventfully. In retrospect, almost all patients had a history of chronic maxillary sinusitis or trauma to the operated area. CONCLUSION Hyperbaric oxygen therapy seems to be an effective adjunctive therapy in the treatment of nonirradiated patients with compromised intraoral maxillary bone graft healing. Chronic maxillary sinus problems or a history of trauma could predispose to wound dehiscence after bone grafting.

Veranderingen in hartfrequentie tijdens poliklinische verwijdering van een verstandskies

Bij een kaakchirurgische behandeling is het gebruikelijk dat patienten in meer of mindere mate bang zijn; het beloop hiervan tijdens de behandeling is echter onbekend. Om meer inzicht te verkrijgen in het verloop van de ‘stress’ werd tijdens het operatief verwijderen van een verstandskies de hartfrequentie continu gemeten. Veranderingen in de hartfrequentie zijn een maat voor stress/angst. Bij 48 patienten werd de hartfrequentie tijdens de behandeling continu geregistreerd als een functie van de achtereenvolgende gebeurtenissen: plaatsnemen in de wachtkamer, in de tandartsstoel, bij de toediening van lokale anesthesie, het afdekken met steriele doeken, de time-out procedure, de incisie, de alveolotomie, het verwijderen van de verstandskies, het hechten en het einde van de procedure. Preoperatieve stress werd gescoord met de Modified Dental Anxiety Scale. Het bleek dat de intensiteit en het tijdsbeloop van stress tijdens het operatief verwijderen van een verstandskies een specifiek patroon laten zien, waarbij de periode direct voor het daadwerkelijk verwijderen van de verstandskies de meest stressvolle periode is.

The influence of three barrier membranes on modeling and incorporation of autologous onlay bone grafts in rats. An evaluation by transversal microradiography.

OBJECTIVES To determine whether covering an autologous bone grafts with three different barrier membranes prevents graft resorption, and to compare these membranes to each other. DESIGN In 192 rats a standardised 4.0mm diameter bone graft was harvested from the right mandibular angle and transplanted to the left. Membranes used to cover the grafts were a new poly(DL-lactide-epsilon-caprolactone) membrane, a collagen and expanded polytetrafluoroethylene membrane. The controls were left uncovered. Graft resorption and incorporation were measured with transversal microradiography (TMR) in the four groups at 2, 4 and 12 weeks. Data were analysed using multiple regression analyses. RESULTS Overall, there were no differences in modeling with resorption between the four groups. ePTFE at 12 weeks showed a lower mineralization ratio and graft height of the graft as compared to the other groups. The mean graft incorporation was progressive and nearly identical from 2 to 12 weeks in all groups. CONCLUSIONS Membranes have an equal effect on bone graft modeling and resorption as found in non-covered controls. Therefore, the indication to use a barrier membrane to prevent bone modeling with resorption and enhance incorporation of autologous onlay bone grafts is disputable.