Dynamic Navigation for Dental Implant Placement.

In modern implantology, the application of surgical navigation systems is becoming increasingly important. In addition to static surgical navigation methods, a guide-independent dynamic navigation implant placement procedure is becoming more widespread. The procedure is based on computer-guided dental implant placement utilizing optical control. This work aims to demonstrate the technical steps of a new dynamic computer-aided implant surgery (DCAIS) system (design, calibration, surgery) and check the accuracy of the results. Based on cone-beam computed tomography (CBCT) scans, the exact positions of implants are determined with dedicated software. The first step of the operation is the calibration of the navigation system, which can be performed in two ways: 1) based on CBCT images taken with a marker or 2) based on CBCT images without markers. Implants are inserted with the aid of real-time navigation according to the preoperative plans. The accuracy of the interventions can be evaluated based on postoperative CBCT images. The preoperative images containing the planned positions of the implants and postoperative CBCT images were compared based on the angulation (degree), platform, and apical deviation (mm) of the implants. To evaluate the data, we calculated the standard deviation (SD), mean, and standard error of the mean (SEM) of deviations within planned and performed implant positions. Differences between the two calibration methods were compared based on this data. Based on the interventions performed so far, the use of DCAIS allows for high-precision implant placement. A calibration system that does not require labeled CBCT recording allows for surgical intervention with similar accuracy as a system that uses labeling. The accuracy of the intervention can be improved by training.

Iterative Ring Artifact Removal Method for Helical Computed Tomography Scans.

OBJECTIVE: In this article, a statistical-based iterative ring removal (IRR) algorithm that effectively removes ring artifacts generated by defective detector cells is proposed. METHODS: The physical state of computed tomography (CT) detector elements can change dynamically owing to their temperature dependence and the varying irradiation caused by focal spot movements. This variation in the properties of cells may cause false pixel values in sinograms, resulting in rings or segments of rings in reconstructed images. In this article, the proposed algorithm is studied on clinical CT. Two patients were scanned using a clinical CT scanner (AnyScan SPECT/CT, Mediso). Artificial rings and band rings were generated on the real sinogram data to examine the algorithm in different cases. The method was performed also on real ring artifacts. RESULTS: The IRR can correct both single and band-like ring artifacts with one or more defective pixels. The proposed algorithm can detect the period when pixels contain false signals and only those periods are corrected. The IRR reduces ring artifacts, even in cases where low-contrast rings occur in the reconstructed image. CONCLUSIONS: This statistical correction method efficiently detects and corrects false pixel values in the projection data without causing new artifacts in the reconstructed image. The algorithm is less sensitive to its parameters.

A Review of Techniques for Closure of the Pancreatic Remnant following Distal Pancreatectomy.

The prevalence of pancreatic diseases needing surgical intervention is continuously rising. Distal pancreatectomy is performed in the case of pathologies affecting the left side of the pancreas. More and more sophisticated surgical techniques have appeared and an increasing number of published articles discuss the possibilities for closure of the pancreatic remnant. However, the optimum solution is still under debate, as none of the examined techniques have been proven superior in reducing the incidence of the most common surgical complication, the formation of a postoperative pancreatic fistula (PF). Fistula rates have been stationary at 20-30% in the past decades despite the apparent advancement of medicine. This review presents a survey of the relevant articles examining different closure strategies and risk factors to reduce fistula formation rate. International medical publication database search and assessment was carried out to include the findings of studies investigating the efficacy of pancreatic remnant closure techniques to gain a clearer view on the complexity of pancreas fistulas. Emphasis is on indications for surgery, risk factors for postoperative fistula formation and strategies to seal the pancreatic remnant to avoid leakage. Findings suggest that careful patient selection, meticulous surgical techniques are equally important to reduce fistula rates. Ideal closure of the pancreatic remnant is still to be developed, as none of the widespread techniques (hand-sewn suture or staple closure) proved to be statistically significantly superior. Additional closure and covering methods (seromuscular patch, falciform ligament patch, pancreatico-enteric anastomosis, reinforced staplers, fibrin glue etc.) can have profitable effect but strong evidences are yet to come due to small case numbers. The recent introduction of standardized classification of PFs and future prospective randomized trials are more likely to be susceptible to determine if any of the standard or experimental closure techniques is more beneficial than the others.

Five-year results evaluating the effects of platelet-rich plasma on the healing of intrabony defects treated with enamel matrix derivative and natural bone mineral.

BACKGROUND: Regenerative periodontal surgery using the combination of enamel matrix derivative (EMD) and natural bone mineral (NBM) with and without addition of platelet-rich plasma (PRP) has been shown to result in substantial clinical improvements, but the long-term effects of this combination are unknown. METHODS: The goal of this study was to evaluate the long-term (5-year) outcomes after regenerative surgery of deep intrabony defects with either EMD + NBM + PRP or EMD + NBM. Twenty-four patients were included. In each patient, one intrabony defect was randomly treated with either EMD + NBM + PRP or EMD + NBM. Clinical parameters were evaluated at baseline and 1 and 5 years after treatment. The primary outcome variable was clinical attachment level (CAL). RESULTS: The sites treated with EMD + NBM + PRP demonstrated a mean CAL change from 10.5 ± 1.6 to 6.0 ± 1.7 mm (P <0.001) at 1 year and 6.2 ± 1.5 mm (P <0.001) at 5 years. EMD + NBM-treated defects showed a mean CAL change from 10.6 ± 1.7 to 6.1 ± 1.5 mm (P <0.001) at 1 year and 6.3 ± 1.4 mm (P <0.001) at 5 years. At 1 year, a CAL gain of ≥4 mm was measured in 83% (10 of 12) of the defects treated with EMD + NBM + PRP and in 100% (all 12) of the defects treated with EMD + NBM. Compared to baseline, in both groups at 5 years, a CAL gain of ≥4 mm was measured in 75% (nine of 12 in each group) of the defects. Four sites in the EMD + PRP + NBM group lost 1 mm of the CAL gained at 1 year. In the EMD + NBM group, one defect lost 2 mm and four other defects lost 1 mm of the CAL gained at 1 year. No statistically significant differences in any of the investigated parameters were observed between the two groups. CONCLUSIONS: Within their limits, the present results indicate that: 1) the clinical outcomes obtained with both treatments can be maintained up to a period of 5 years; and 2) the use of PRP does not appear to improve the results obtained with EMD + NBM.

[Comparison of autologous bone graft remodeling from different donor sites in the jaws using cone beam computed tomography]. / Állcsontdefektusok augmentációjához használt autológ csontok átépülésének vizsgálata Cone Beam CT-vel.

With the spread of endosteal implants bone grafting has become frequently used procedure in the area of the jaws, primarily for the augmentation of the alveolar process and the sinus maxillaris. Although various assortments of bone replacement materials are available nowadays, autologous bone graft still remains the 'gold standard'. Autologous bone depending on the required quantity for the procedure can be harvested from intra- or extraoral sources. The properties and quality of bone grafts depend on the structure (cortical or/and spongious), the embryological origin (endochondral or membranous) and the donor site (extra- or intraoral). The pros and cons of different donor sites are being researched and evaluated upon, as only the correct technique of bone harvesting can guarantee the success of the the surgical procedure. In the Department of Oro-Maxillofacial Surgery and Stomatology at Semmelweis University, 12 patients participated in the research study, the bone replacement surgeries were performed with autologous bone because of an extended bony defect. The patients were classified by the donor sites. By the examination of autologous bone grafts remodeling, the lowest density change has been measured in the tibia grafts and the lowest extent change was in the calvaria grafts. Pathological absorption was not seen in any of the cases, which concludes that all of the grafts can be used if correct surgical technique is followed.

[Dentigerous cyst associated with a wisdom tooth in the maxillary sinus. Case reports, review of the literature]. / Arcüreg felé attöro, follikuláris cisztával körülvett bölcsességfogak. Esetismertetés, irodalmi attekintés.

Wisdom teeth are often impacted or in an ectopic position. One rather special localisation is the maxillary sinus. Usually these teeth are associated with dentigerous cysts, which can occupy the maxillary sinus partially or totally and can be the cause of various symptoms. We can find it at routine radiographic examination or the patient could have typical, sinus-related symptoms. This signs can be swelling, pain of the cheek, headeache and nasolacrimal obstruction. We report four cases (one of them detailed) with review of the literature where the upper wisdom tooth is situated in the maxillary sinus.

[The effect of taboo word on language processing]. / A tabszvak hatása lexikális döntési helyzetben.

Knowledge about how we process taboo words brings us closer to the and emotional processes, and broadens the interpretative framework in psychiatry and psychotherapy. In this study the lexical decision paradigm was used. Subjects were presented neutral words, taboo words and pseudowords in a random order, and they had to indicate whether the presented word was meaningful (neutral and taboo words) or meaningless (pseudowords). Each target word was preceded by a prime word (either taboo or neutral). SOA differed in the two experimental conditions (it was 250 msec in the experimental group, and 500 msec in the control group). In the experimental group, response latencies increased for target words that were preceded by taboo prime words, as compared to those that were preceded by neutral prime words. In the control group prime had no such differential effects on response latencies. Results indicate that emotional processing of taboo words occur very early and the negative effect of taboo words on the following lexical decision fades away in 500 msec. Our experiment and other empirical data are presented in this paper.

Effect of platelet-rich plasma on the healing of intrabony defects treated with an anorganic bovine bone mineral: a pilot study.

BACKGROUND: Periodontal therapy using the combination of platelet-rich plasma (PRP) and different grafting materials has been suggested as a modality to enhance the outcome of regenerative surgery. In most clinical studies, a barrier membrane was used to cover the defects, and thus, the effects of PRP may have been masked by the effects of the barrier. The data from controlled clinical studies evaluating the effect of regenerative therapy using various grafting materials with or without PRP are still limited. The purpose of this study was to clinically compare the healing of intrabony defects treated with either a combination of an anorganic bovine bone mineral (ABBM) and PRP to those obtained with ABBM alone. METHODS: Thirty patients with advanced chronic periodontal disease and displaying one intrabony defect were randomly treated with PRP + ABBM or ABBM alone. The following clinical parameters were evaluated at baseline and 1 year after treatment: plaque index (PI), gingival index (GI), bleeding on probing (BOP), probing depth (PD), gingival recession (GR), and clinical attachment level (CAL). The primary outcome variable was CAL. RESULTS: No statistical significant differences in any of the investigated parameters between the two groups were observed at baseline. Healing was uneventful in all patients. In the PRP + ABBM group, mean PD decreased from 8.6 +/- 1.8 mm to 3.4 +/- 1.4 mm (P <0.001) and mean CAL changed from 9.9 +/- 1.7 mm to 5.3 +/- 1.8 mm (P <0.001). In the ABBM group, mean PD decreased from 8.5 +/- 2.0 mm to 3.2 +/- 1.3 mm (P <0.001) and mean CAL changed from 9.6 +/- 1.9 mm to 4.9 +/- 1.5 mm (P <0.001). CAL gains >or=3 mm were measured in 80% (12 of 15 defects) of cases treated with PRP + ABBM and in 87% (13 of 15 defects) of cases treated with ABBM alone. No statistically significant differences in any of the investigated parameters were observed between the two groups at the 1-year reevaluation. CONCLUSIONS: Within the limits of the present study, it can be concluded that 1) at 1 year after regenerative surgery with PRP + ABBM and ABBM alone, significant PD reductions and CAL gains were found, and 2) the use of PRP failed to improve the results obtained with ABBM alone.

[Comparison of postoperative complications following bone harvesting from two different donor sites for autologous bone replacement (hip bone and proximal epiphysis of the tibia)]. / Autológ csontpótláshoz igénybe vett két, különbözo donorhely (csípolapát és tibia proximalis epiphysise) mutét utáni szövodményeinek összehasonlítása.

Whereas autologous bone replacement was earlier applied in maxillofacial surgery virtually only for the restoration of mandibular defects and for the osteoplasty of patients with cleft alveolar process, the free transplantation of autologous bone (spongiosa or cortical bone or both) is nowadays primarily used for implantation purposes. Autologous bone is still the gold standard for bone replacement. This is the case even though a wide selection of bone substitutes is currently available, with which new bone equivalent to autologous bone can be produced in certain cases. Autologous bone is often obtained from intraoral sources, but if a larger quantity of spongiosa is required, these sites (the chin, the retromolar area of the mandible, the muscular process, etc.) are not suitable. Of the extraoral donor sites, the most frequently used site is the iliac crest, but the proximal epiphysis of the tibia is also appropriate for this purpose since we have recently performed bone transplantations on appreciable numbers of patients, we decided to compare the morbidity data relating to the two donor sites. In the 9 months between March and November 2007, sinus elevations were carried out on 14 patients with bone taken from the tibia, while in 38 patients bone was taken from the iliac crest for osteoplasty on clefted alveolar process. The comparison was based on postoperative clinical examinations, the complaints of the patients and objective study of the morbidity relating to the two donor sites. Clinically the patients tolerated both interventions well. Mobilization took place on the day of intervention. There were no major complications; one minor haematoma was observed after each type of surgery. The postoperative complaints of the patients did not reveal any essential difference. Following bone harvesting from the iliac crest, the gait of the patients slightly hampered for up to 10 to 14 days. In the tibia cases, the patients experienced no pain on walking by the second day. As regards donor site morbidity, protracted (1-2 weeks) oedema was observed after hip surgery, with paraesthesia of the area of innervation of the n. cutaneous femoris lateralis in 1 case, while there was a minor seroma following tibia surgery in 1 case. Our clinical experience suggests that, if 10-15 cm(3) spongiosa is required for augmentation purposes and there is no need for cortical bone, the patient is exposed to less stress when bone is taken from the proximal epiphysis of the tibia.

[The proximal tibia. A possible donor site in preprosthetic surgery]. / A tibia proximalis epiphysise mint lehetséges autológ csontvételi hely.

With the development of oral implantology the augmentation of the alveolar process and the maxillary sinus has become a more and more frequent procedure. Even though a vast array of bone replacement materials is available commercially, they all just have an osteoconductive effect. By now it has become clear that the 'gold standard' of bone grafts is autologous bone that is both osteoconductive and osteoinductive. Autologous bone is mostly harvested from intraoral sources. If a larger quantity of spongious bone is needed, it is from extraoral sites, mainly from the iliac crest. In some countries the use of the proximal epiphysis of the tibia for bone harvesting is more widespread. In our Department a sinus lift was performed with spongious bone harvested from the tibia in 14 patients within 9 months. A mean 20 cc of bone can be harvested from one site, which is sufficient for the augmentation of both sinus floors in all cases. The patients tolerated surgery well, healing was without complications. Patients were mobilised immediately after surgery. Patients tolerated the postoperative period significantly better than after bone harvesting from the iliac crest.

Effect of platelet-rich plasma on the healing of intrabony defects treated with Beta tricalcium phosphate and expanded polytetrafluoroethylene membranes.

BACKGROUND: Regenerative periodontal therapy using platelet-rich plasma (PRP) and different types of bone substitutes with or without guided tissue regeneration (GTR) has been proposed as a modality to enhance the outcome of regenerative surgery. However, there are limited data from controlled clinical studies evaluating the effect of PRP on the healing of deep intrabony defects treated with a combination of bone substitutes and GTR. The aim of this study was to clinically evaluate the effect of PRP on the healing of deep intrabony defects treated with beta tricalcium phosphate (beta-TCP) and GTR by means of a non-bioresorbable expanded polytetrafluoroethylene membrane. METHODS: Twenty-eight subjects with advanced chronic periodontal disease and displaying one intrabony defect were treated randomly with a combination of PRP + beta-TCP + GTR or beta-TCP + GTR. Plaque index, gingival index, bleeding on probing, probing depth (PD), gingival recession, and clinical attachment level (CAL) were evaluated at baseline and at 1 year after treatment. CAL was the primary outcome variable. RESULTS: No differences in any of the investigated parameters were observed at baseline between the two groups. Healing was uneventful in all subjects. At 1 year after therapy, the sites treated with PRP + beta-TCP + GTR showed a reduction in mean PD from 9.1 +/- 0.6 mm to 3.3 +/- 0.5 mm (P <0.001) and a change in mean CAL from 10.1 +/- 1.3 mm to 5.7 +/- 1.1 mm (P <0.001). In the group treated with beta-TCP + GTR, mean PD was reduced from 9.0 +/- 0.8 mm to 3.6 +/- 0.9 mm (P <0.001), and the mean CAL changed from 9.9 +/- 1.0 mm to 5.9 +/- 1.2 mm (P <0.001). In both groups, all sites gained > or =3 mm of CAL. CAL gains > or =4 mm were noted in 86% (12 of 14 defects) of the cases treated with PRP + beta-TCP + GTR and in 79% (11 of 14 defects) of those treated with beta-TCP + GTR. No statistically significant differences in any of the investigated parameters were observed between the two groups at the 1-year reevaluation. CONCLUSION: At 1 year after surgery, both therapies resulted in significant PD reductions and CAL gains.

Effect of platelet-rich plasma on the healing of intrabony defects treated with an enamel matrix protein derivative and a natural bone mineral.

BACKGROUND: Regenerative periodontal surgery utilizing a combination of an enamel matrix protein derivative (EMD) and a natural bone mineral (NBM) and platelet-rich plasma (PRP) has been shown to enhance the outcomes of regenerative surgery significantly. At present, it is unknown whether root conditioning with EMD, followed by defect fill with a combination of NBM+PRP may additionally enhance the clinical results obtained with EMD+NBM. AIM: To compare clinically the treatment of deep intrabony defects with either EMD+NBM+PRP or EMD+NBM. MATERIAL AND METHODS: Twenty-six patients suffering from advanced chronic periodontitis, and each of whom displayed one advanced intrabony defect were randomly treated with either EMD+NBM+PRP (test) or EMD+NBM (control). The following clinical parameters were evaluated at baseline and at 1 year after treatment: plaque index (PI), gingival index (GI), bleeding on probing (BOP), probing depth (PD), gingival recession (GR) and clinical attachment level (CAL). The primary outcome variable was CAL. RESULTS: Healing was uneventful in all patients. At 1 year after therapy, the test sites showed a reduction in mean PD from 8.8+/-1.9 mm to 3.1+/-0.9 mm ( p<0.001) and a change in mean CAL from 10.8+/-2.0 mm to 6.0+/-1.5 mm ( p<0.001). In the control group the mean PD was reduced from 8.8+/-2.0 mm to 2.8+/-1.6 mm ( p<0.001) and the mean CAL changed from 10.5+/-1.6 mm to 5.5+/-1.4 mm ( p<0.001). CAL gains of > or =4 mm were measured in 77% (i.e. in 10 out of 13 defects) of the cases treated with EMD+NBM+PRP and in 100% (i.e. in all 13 defects) treated with EMD+NBM. No statistically significant differences in any of the investigated parameters were observed between the two groups. CONCLUSIONS: Within its limits, the present study has shown that (i) 1 year after regenerative surgery, both treatments resulted in statistically significant PD reductions and CAL gains and (ii) the use of PRP failed to enhance the results obtained with EMD+NBM.

Effect of platelet-rich plasma on the healing of intrabony defects treated with an anorganic bovine bone mineral and expanded polytetrafluoroethylene membranes.

BACKGROUND: Regenerative periodontal therapy with a combination of platelet-rich plasma (PRP) + an anorganic bovine bone mineral (ABBM) + guided tissue regeneration (GTR) has been shown to result in significantly higher probing depth reductions and clinical attachment level gains compared to treatment with open flap debridement (OFD) alone, ABBM alone, or GTR alone. However, there are no data evaluating to what extent the use of PRP may additionally enhance the clinical outcome of the therapy compared to treatment with ABBM + GTR. This study aimed to clinically evaluate the effect of PRP on the healing of deep intrabony defects treated with ABBM and GTR by means of a non-resorbable expanded polytetrafluoroethylene (ePTFE) membrane. METHODS: Twenty-four patients with advanced chronic periodontal disease and displaying one intrabony defect were randomly treated with a combination of either PRP + ABBM + GTR or ABBM + GTR. The following clinical parameters were evaluated at baseline and at 1 year after treatment: plaque index (PI), gingival index (GI), bleeding on probing (BOP), probing depth (PD), gingival recession (GR), and clinical attachment level (CAL). The primary outcome variable was CAL. RESULTS: No differences in any of the studied parameters were observed at baseline between the two groups. Healing was uneventful in all patients. At 1 year after therapy, the sites treated with PRP + ABBM + GTR showed a reduction in mean PD from 8.6 +/- 1.7 mm to 3.1 +/- 1.3 mm (P <0.001) and a change in mean CAL from 10.3 +/- 1.4 mm to 5.7 +/- 1.6 mm (P <0.001). In the group treated with ABBM + GTR, mean PD was reduced from 8.8 +/- 1.7 mm to 3.1 +/- 1.0 mm (P <0.001), and the mean CAL changed from 10.4 +/- 2.6 mm to 5.9 +/- 1.8 mm (P <0.001). In both groups, all sites gained > or =3 mm of CAL. CAL gains > or =4 mm were measured in 83% (i.e., in 10 of 12 defects) of the cases treated with PRP + ABBM + GTR and in 92% (i.e., in 11 of 12 defects) treated with ABBM + GTR. No statistically significant differences in any of the studied parameters were observed between the two groups at 1-year reevaluation. CONCLUSION: Within its limits, the present study has shown that, at 1 year after regenerative therapy in periodontal intrabony defects, optimal clinical results were obtained with ABBM + GTR with a non-resorbable barrier, with or without the addition of PRP.

Effect of platelet-rich plasma on the healing of intra-bony defects treated with a natural bone mineral and a collagen membrane.

BACKGROUND: Regenerative periodontal therapy with a combination of platelet-rich plasma (PRP)+a natural bone mineral (NBM)+guided tissue regeneration (GTR) has been shown to result in significantly higher probing depth reductions and clinical attachment-level gains compared with treatment with open flap debridement alone. However, at present, it is unknown to what extent the use of PRP may additionally enhance the clinical outcome of the therapy compared with treatment with NBM+GTR. AIM: To clinically compare treatment of deep intra-bony defects with NBM+PRP+GTR with NBM+GTR. MATERIAL AND METHODS: Thirty patients suffering from advanced periodontal disease, and each of whom displayed one advanced intra-bony defect were randomly treated with a combination of either NBM+PRP+collagen membrane (GTR) or NBM+GTR. The following clinical parameters were evaluated at baseline and at 1 year after treatment: plaque index, gingival index, bleeding on probing, probing depth (PD), gingival recession and clinical attachment level (CAL). CAL changes were used as the primary outcome variable. RESULTS: No differences in any of the investigated parameters were observed at baseline between the two groups. Healing was uneventful in all patients. At 1 year after therapy, the sites treated with NBM+PRP+GTR showed a reduction in mean PD from 8.9+/-2.3 mm to 3.4+/-2.0 mm (p<0.001) and a change in mean CAL from 10.9+/-2.2 mm to 6.4+/-1.8 mm (p<0.001). In the group treated with NBM+GTR, the mean PD was reduced from 8.9+/-2.5 mm to 3.4+/-2.3 mm (p<0.001), and the mean CAL changed from 11.1+/-2.5 mm to 6.5+/-2.3 mm (p<0.001). In both groups, all sites gained at least 3 mm of CAL. CAL gains of > or = 4 mm were measured in 80% (i.e. in 12 out of 15 defects) of the cases treated with NBM+PRP+GTR and in 87% (i.e. in 13 out of 15 defects) treated with NBM+GTR. No statistically significant differences in any of the investigated parameters were observed between the two groups. CONCLUSIONS: Within its limits, the present study has shown that (i) at 1 year after regenerative surgery with both NBM+PRP+GTR and NBM+GTR, significant PD reductions and CAL gains were found, and (ii) the use of PRP has failed to improve the results obtained with NBM+GTR.

Modified procedure for secondary facial rehabilitation following total bilateral irreversible peripheral facial palsy.

We present the case of a middle-aged gentleman who developed total bilateral irreversible peripheral facial palsy over a period of 10 years, starting with palsy of the marginal mandibular and buccal branches of the facial nerve and progressing to the zygomatic and temporal branches. The patient did not develop any other neurological symptoms, and all neurological and other tests have remained negative over the last 10 years. Dripping of saliva and inability to close the mouth necessitated reanimation of the perioral region with the help of a fascia lata graft fixed to the fascia of the masseter muscles. The increasing lagophthalmos and associated eye problems were alleviated with a temporal muscle transposition combined with a lengthening procedure using the temporal fascia, passed through the upper and lower eyelids and hooked around the medial canthal ligament. The fascia strips were sutured not to the canthal ligament itself, but to each other, thereby placing equal self-adjusted tension on the upper and lower eyelids. Both operations were successful and improved eating and eye closure functions, allowing resolution of the eye symptoms.

[The clinical importance of the mandibular canal course variations]. / A canalis mandibulae lefutádának variációi és azok klinikai jelentosége.

The authors review the literature relating to anatomical variations of mandibular canals. They compare the results of their examinations with the literature data. The proportion of duplicated mandibular canal observed during macroscopic examinations of mandibles proved to be substantially higher than that revealed by X-ray pictures. The knowledge of the course of the mandibular canal and its anatomical variations is of great importance in certain oral surgical interventions, such as preprosthetic operations and the insertion of enosseal implants, and during the planning of removable dentures prepared in cases involving extensively atrophied mandibles. The authors review the possible consequences of the injury of accessory mandibular canal.

[Parotid gland Warthin's tumor combined with actinomycosis]. / Actinomycosissal kombinált, parotisban elhelyezkedo Warthin-tumor ritka esete.

The authors describe the diagnostic problems and difficulties of treatment of Warthin's tumor combined with actinomycosis. A 48-year-old woman was presented with a mass in the left parotid region and paresis of the lower left palpebra. The CT, echography, parotid X-ray findings supposed a neoplasm of the left parotid gland which was proved by intraoperative freezing histology. The ramus of the mandible was involved in the process. Total parotidectomy and partial mandiblectomy were performed, with sacrifice of the facial nerve, followed by nerve reconstruction. The final histological evaluation was Warthin's tumor with actinomycosis. Eight years after treatment the patient is free of disease.

Atypical courses of the mandibular canal: comparative examination of dry mandibles and x-rays.

Knowledge of the course of the mandibular canal and its anatomic variations is of great importance in oral surgery, especially in preprosthetic operations and the insertion of endosteal implants and during the planning of removable dentures prepared in cases involving extensively atrophied mandibles. We review the literature on duplicated mandibular canals, which is based exclusively on radiologic findings. Then, we compare this with an examination of dry mandibles and further radiologic studies. The incidence of duplicated mandibular canals observed in macroscopic examinations of mandibles was substantially higher than that revealed by radiographs. One case involving a novel variation, a triple mandibular canal, is reported.

[Total upper lip necrosis and loxoscelism caused by violin spider bite]. / Pókcsípés okozta loxoscelizmus nagykiterjedésu felso ajak nekrózissal.

Arthropods and in particular spiders are a common embodiment of our fears, despite the fact that only a few species are dangerous to man. The authors present a case involving severe local and general reactions to a loxosceles (brown recluse spider) bite. They give an overview of the occurrence of loxosceles spiders, the signs and symptoms of envenomation and the therapeutic possibilities. The severe symptoms presenting following loxosceles envenomation is termed loxoscelism. Loxoscelism is characterised by local soft tissue necrosis of varying degree at the site of the sting, and rarely, life-threatening general reactions, such as haemolysis with ensuing anaemia, and renal failure. Therapeutic interventions following loxosceles bites range from dapsone treatment to hyperbaric oxygen therapy, but the most promising therapy is the use of the antiserum, commercially available in certain South-American countries where loxosceles bites are common. Treatment of soft tissue necrosis consists of necrectomy and surgical reconstruction following the resolution of the inflammatory symptoms.

Histomorphometric and densitometric evaluation of the effects of platelet-rich plasma on the remodeling of beta-tricalcium phosphate in beagle dogs.

Countless possibilities are available in maxillofacial surgery for the filling of bone defects. The best bone substitute known at present is osteogenic autogenous bone, but its use is accompanied by numerous disadvantages. The question has arisen of whether results attained with osteoconductive bone substitutes approach those achieved by the transplantation of autogenous bone. The aims of the investigation were to measure the effects in animal experiments of the growth factors to be found in the platelets on the rate of remodeling of beta-tricalcium phosphate, and on the quality of the new bone formed. Defects formed in the mandibles of 10 Beagle dogs were filled with beta-tricalcium phosphate or with a mixture of beta-tricalcium phosphate and platelet-rich plasma obtained from autogenous blood. The quality of the hard tissue formed and the effect of the platelet-rich plasma were examined by statistical analysis of the densitometric results obtained after 6 weeks and the histological and histomorphometric results obtained after 12 weeks. The densitometric study revealed that the bone formation was significantly more effective when platelet-rich plasma was used; at this stage, histomorphometric evaluation did not indicate a significant difference. After 12 weeks, however, the histomorphometric study demonstrated a significant difference in favor of the bone substitute used together with platelet-rich plasma. The results strongly suggest that use of the platelet-rich plasma suspension accelerates the remodeling of beta-tricalcium phosphate and leads to the formation of hard tissue with a quality similar to that of the autogenous bone.