A systematic review and meta-analysis on the influence of biological implant surface coatings on periimplant bone formation.

This systematic review and meta-analysis evaluated the influence of biological implant surface coatings on periimplant bone formation in comparison to an uncoated titanium reference surface in experimental large animal models. The analysis was structured according to the PRISMA criteriae. Of the1077 studies, 30 studies met the inclusion criteriae. Nineteen studies examined the bone implant contact (BIC) and were included in the meta-analysis. Overall, the mean increase in BIC for the test surfaces compared to the reference surfaces was 3.7 percentage points (pp) (95% CI -3.9-11.2, p = 0.339). Analyzing the increase in BIC for specific coated surfaces in comparison to uncoated reference surfaces, inorganic surface coatings showed a significant mean increase in BIC of 14.7 pp (95% CI 10.6-18.9, p < 0.01), extracellular matrix (ECM) surface coatings showed an increase of 10.0 pp (95% CI 4.4-15.6, p < 0.001), and peptide coatings showed a statistical trend with 7.1 pp BIC increase (95% CI -0.8-15.0, p = 0.08). In this review, no statistically significant difference could be found for growth factor surface coatings (observed difference -3.3 pp, 95% CI -16.5-9.9, p = 0.6). All analyses are exploratory in nature. The results show a statistically significant effect of inorganic and ECM coatings on periimplant bone formation. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2898-2910, 2016.

Inferior alveolar nerve function after open reduction and internal fixation of mandibular fractures.

PURPOSE: Mandibular fractures are amongst the most common facial fractures and are usually treated by open reduction and internal fixation (ORIF). Inferior alveolar nerve (IAN) injuries are seen frequently in mandibular fractures as well as after ORIF of these fractures due to the exposition and the close proximity of the nerve during fracture reduction. Therefore the continuity of the IAN can be disrupted. Permanent injury to the IAN can result in diminished quality of life. This retrospective study was designed to objectively analyse the incidence and the outcome of pre- and postoperative mental nerve hypoesthesia after ORIF of mandibular fractures. MATERIAL AND METHODS: Patients who were consecutively treated at the Department of Cranio-Maxillofacial and Oral Surgery of the University Hospital Zurich between 2004 and 2010 with mandibular fractures who underwent ORIF were included. Follow-up period was 12 months. Demographic, pre-, peri- and postsurgical data were tabulated and statistically evaluated using the χ(2) test and the Kruskall-Wallis-Test. RESULTS: 340 patients met the inclusion criteria. 27% of the study population presented with postinjury (preoperative) mental nerve hypoesthesia, 46% suffered from purely postoperative hypoesthesia and 27% showed no nerve damage. Complete recovery was seen in 70% of all cases, partial recovery in 20% of the cases and less than 10% suffered from a permanent (>12 months) IAN damage. Mandibular angle fractures were accompanied with significantly higher rates of hypoesthesia (79% vs. 68%). Recovery rate was significantly worse in older patients, when preoperative hypoesthesia was present (66% vs. 73%) and in patients with multiple fractures in proximity to the IAN (36% vs. 52%). Mandibular body fractures showed worse recovery rates than fractures that did not affect the body (44% vs. 52%). CONCLUSION: The present study shows that IAN injury is seen frequently in mandibular fractures. Mental nerve hypoesthesia may influence quality of life. Nerve continuity may not be preserved due to the initial trauma or may result as a postoperative complication. Nevertheless the results of this study show a high potential for full recovery.

Fallpräsentation: Kiefergelenkbeschwerden als erstes Zeichen einer malignen Erkrankung.

CASE REPORT: TMJ-like symptoms as first sign of a tumorous disease. Metastasis as an uncommon origin of the symptoms (in German).

Frequency and anatomy of the retromolar canal - implications for the dental practice.

The retromolar canal (RMC) is an anatomical variant of the mandibular canal. Apart from blood vessels it also contains accessory nerve fibers and is clinically important, because its presence can account for failures of mandibular block anesthesias and in rare cases, injuries of its neurovascular bundle can lead to complications such as hemorrhages and dysesthesias. The aim of this retrospective case study was to analyze the frequency and anatomy of the RMC using cone beam computed tomography (CBCT) in order to draw conclusions for the dental practice. A total of 680 CBCT scans comprising 1,340 mandibular sides were evaluated. A total of 216 RMCs (16.12%) were found. The most common appearance of the canal (39.82%) corresponded to type Al (vertical course), whereas type C (horizontal course) occurred least often (6.02%). Mean measured values were 1.03 mm (SD=0.27mm) regarding the RMC diameter, 10.19 mm (SD=2.64mm) regarding the RMC height and 15.10 mm (SD=2.83 mm) regarding the distance of the RMC to the second molar. Neither demographic factors nor the spatial resolution of the CBCT had a statistically significant impact on the frequency of the RMC. Since the present study revealed a frequency of RMCs amounting to 16.12% (corresponding approximately to every sixth retromolar area), we recommend to spare it during surgery or to consider an additional locoregional anesthesia in the retromolar region. For preoperative diagnosis the CBCT has proved suitable, offering the possibility to select the spatial resolution depending on the indication, so that radiation exposure is reduced without a decrease in validity.

Anatomic (positional) variation of maxillary wisdom teeth with special regard to the maxillary sinus.

The removal of wisdom teeth is one of the most common interventions in oral surgery. In order to avoid complications, a profound knowledge of the anatomy of teeth and adjacent tissues is crucial. In the case of maxillary wisdom teeth, their relationship to the maxillary sinus, to the pterygoid fossa, to the maxillary tuber and the adjacent venous plexus is particularly important. Three-dimensional (3D) imaging, for example by means of cone beam computed tomography (CBCT), is increasingly utilized in practice. However, the necessity of CBCT imaging is still a matter of intensive debate. The aim of this study was to describe the anatomic (positional) variation of maxillary wisdom teeth and, based on these findings, to elucidate the additional benefit of such imaging. A retrospective case study was performed using patients examined by means of CBCT imaging in the Department of Dento-Maxillofacial Radiology during the period from 2008 to 2013. Primary study variables comprised the spatial relationship of the teeth to the maxillary sinus, the degree of retention and root development, the covering of the root with bone and mucosa, the root configuration, and the developmental stage of the tooth. In addition, the association of the inclination of teeth in the transversal and sagittal plane with the above variables was evaluated. Descriptive statistical parameters were calculated for all results of the examination. In total, CBCT recordings of 713 maxillary wisdom teeth from 430 patients were evaluated. Their mean age was 29.8 years, and the proportion of male patients slightly prevailed (54.4%). Most teeth exhibited fully developed roots (64.1%). Overall 22.9% of third molars were impacted, 32.3% were retained, and 6.5% were erupting. In more than a third of the patients, wisdom teeth were in occlusion. The inclination of the third molars both in the transversal and sagittal plane was significantly associated with the distance of the root from the maxillary sinus as well as with the bony covering of the root. Owing to the possibility of evaluating preoperatively the relationship of a wisdom tooth to the maxillary sinus and to other anatomic structures, we recommend the use of CBCT, whenever conventional radiography fails to provide adequate information about the critical anatomic circumstances of maxillary third molars. However, CBCT should, at least nowadays, not be utilized as the standard radiographic examination.

Evaluation of the maxillary sinus in panoramic radiography-a comparative study.

BACKGROUND: The aim of this study was to evaluate the validity and the inter- and intra-examiner reliability of panoramic-radiograph-driven findings of different maxillary sinus anatomic variations and pathologies, which had initially been prediagnosed by cone beam computed tomography (CBCT). METHODS: After pairs of two-dimensional (2D) panoramic and three-dimensional (3D) CBCT images of patients having received treatment at the outpatient department had been screened, the predefinition of 54 selected maxillary sinus conditions was initially performed on CBCT images by two blinded consultants individually using a questionnaire that defined ten different clinically relevant findings. Using the identic questionnaire, these consultants performed the evaluation of the panoramic radiographs at a later time point. The results were analyzed for inter-imaging differences in the evaluation of the maxillary sinus between 2D and 3D imaging methods. Additionally, two resident groups (first year and last year of training) performed two diagnostic runs of the panoramic radiographs and results were analyzed for inter- and intra-observer reliability. RESULTS: There is a moderate risk for false diagnosis of findings of the maxillary sinus if only panoramic radiography is used. Based on the ten predefined conditions, solely maxillary bone cysts penetrating into the sinus were frequently detected differently comparing 2D to 3D diagnostics. Additionally, on panoramic radiographs, the inter-observer comparison demonstrated that basal septa were significantly often rated differently and the intra-observer comparison showed a significant lack in reliability in detecting maxillary bone cysts penetrating into the sinus. CONCLUSIONS: Panoramic radiography provides the most information on the maxillary sinus, and it may be an adequate imaging method. However, particular findings of the maxillary sinus in panoramic imaging may be based on a rather examiner-dependent assessment. Therefore, a persistent and precise evaluation of specific conditions of the maxillary sinus may only be possible using CBCT because it provides additional information compared to panoramic radiography. This might be relevant for consecutive surgical procedures; consequently, we recommend CBCT if a precise preoperative evaluation is mandatory. However, higher radiation dose and costs of 3D imaging need to be considered.

[Metastases in the temporomandibular joint: a review from 1954 to 2013. Rare causes for temporomandibular disorders]. / Metastasen im Kiefergelenk: Ein Literaturüberblick von 1954 bis 2013. Seltene Ursachen von Kiefergelenkbeschwerden.

INTRODUCTION: Metastatic lesions make up approximately 1% of all oral cancers.A comparatively rare location is the temporomandibular joint.Leading symptoms can be misdirecting, especially in the beginning,because they are frequently similar or even identical to those occurring in temporomandibular disorders. Therefore it can be quite difficult to confirm the diagnosis of a TMJ metastasis.delayed initiation of therapy and thus a poor prognosis are often the results. MATERIAL AND METHODS: A review of the literature from 1954 to 2013 was realized and the published cases between 1954 and January 2013 were evaluated.The results were analyzed according to gender distribution, age,first symptoms, location of the primary tumor, as well as to the occurrence of malignancies in the patients' medical history. RESULTS: The research identified sixty-six patients. Tumors of the lung and breast were the main starting points of the metastatic spread. The histopathological workup showed above all the diagnosis of an adenocarcinoma. In all of the cases, unspecific symptoms led to the diagnosis of a metastatic disease. CONCLUSION AND SIGNIFICANCE: In the case of nonspecific TMJ affection, diagnostics should consider less-frequent diagnoses, such as the presence of metastasis.A clinical differentiation by additional symptoms like swelling, unexplained weight loss and night sweats, as well as a tumor disease in the past or failure of conservative treatment can provide additional indications. If there is reasonable suspicion,extended medical imaging and diagnostic measures must be performed to allow early treatment initiation and a better prognosis.

Variations in the anatomical positioning of impacted mandibular wisdom teeth and their practical implications.

Surgical removal of impacted third molars is one of the most frequent procedures in oral surgery. Here, three-dimensional (3D) imaging is often used, yet its necessity is still being heavily debated. The aim of the study was to describe the variation in the anatomical positioning of third mandibular molars, and, by doing so, examine the necessity of 3D imaging. A retrospective case study was performed with the patients from an oral surgery department from January 2009 to February 2013. The primary focus of the study was on the spatial relationship to the mandibular canal, as well as angulation, root configuration, and developmental stage of the wisdom tooth. Descriptive statistics were calculated for these variables. A total of 1197 wisdom teeth in 699 patients were evaluated. 46.7% exhibited direct contact to the mandibular canal, another 28.7% showed close proximity and 24.6% a measurable distance. In 29.0%, the mandibular canal was vestibular and in 23.8% lingual to the wisdom tooth. In 7.4%, it was interradicular and in 0.6% intraradicular. Most teeth had one (21.3%) or two (55.3%) roots. Others had three (17.6%), four (2.0%) or five (0.2%) roots. In 31.4% of the teeth, the root perforated the lingual compact bone, and in 4.3% the vestibular compact bone. 44.4% of the teeth had mesial angulation, 9.7% distal angulation, 35.3% lingual and 2.9% buccal angulation. Due to the anatomical variety, the use of 3D imaging is recommended before surgical removal of mandibular third molars if conventional imaging cannot exclude complicated conditions.

[Thrombosis of the external jugular vein. Case report of a rare cause for pain in the lateral neck]. / Thrombose der vena jugularis externa. Fallbericht einer ungewöhnliche Ursache für Schmerzen im seitlichen Halsbereich.

Dental practitioners are sometimes confronted with patients complaining about pain in the neck area. Especially if an induration in the region of the big vessels is present, one must keep in mind the differential diagnosis of a spontaneous thrombosis of the external jugular vein. This diagnosis needs consequent treatment but also consequent search for an underlying pathology. This case report presents such a situation in an exemplary way. Despite risk factors, the reason for thrombosis stays in the dark. However, all possible causes were cleared and are shown to the reader. Especially malignancies are responsible for thrombosis of the jugular vein in many cases.

Stafne bone cavities: systematic algorithm for diagnosis derived from retrospective data over a 5-year period.

Stafne bone cavities are usually found in men 50-70 years old. Typically they appear as lingual, open, ovoid lesions of the molar region of the lower jaw, and most contain parts of the submandibular gland. We have retrospectively examined panoramic radiographs acquired over a 5-year period. All lesions suspected of being Stafne bone cavities were included and analysed further to retrieve statistical information and derive a systematic diagnostic algorithm. We identified 21 Stafne bone cavities among 2928 patients (0.7%). Four of these were confirmed on cone-beam computed tomography (CT). One patient had magnetic resonance imaging (MRI) to confirm the diagnosis. The M:F ratio was 14:7 and the mean age 53 years (range 22-82). All cavities were located in the posterior mandible, 9 on the right and 12 on the left. The mean length was 10.9 (range 4.5-23) mm and height 5.7 (range 3.3-17.3) mm. All cavities were located in the posterior mandible. Sixteen panoramic radiographs (0.6%) were classified as possibly having a Stafne bone cavity but did not fulfil enough criteria to confirm the diagnosis. These 16 were not further analysed. It is rare to diagnose a Stafne bone cavity on a panoramic radiograph. Thorough investigation is essential to exclude differential diagnoses such as keratocystic odontogenic tumour, ameloblastoma, or a metastasis. In atypical presentations 3-dimensional cone-beam CT is helpful to verify the lingual opening. If the diagnosis is still not clear, it can be confirmed by MRI.

Evaluation of two dental registration-splint techniques for surgical navigation in cranio-maxillofacial surgery.

BACKGROUND: Surgical navigation requires precise registration of the pre-operative image dataset to the patient in the operation theatre. Different marker-based and marker-free registration techniques are available, each of them with advantages and disadvantages regarding precision and clinical handling. In this model study, the precision of two dental splint techniques for marker-based registration is analyzed. MATERIALS AND METHODS: A synthetic full-size human skull was registered with its cone beam computed tomography dataset using (a) a dentally-mounted "rapid" occlusal splint with five titanium screws directly attached to the splint, (b) an "extender", a dentally-mounted occlusal splint with similar fiducials fixed to an extension of the splint. The target registration error was measured for 170 landmarks distributed over the viscero- and neurocranium in 10 repeats per splint type using the Vector Vision2 (BrainLAB AG, Heimstetten, Germany) navigation system. Statistical and graphical evaluations were performed per anatomical region. RESULTS: In the periorbital region, the rapid splint, with an average deviation of 1.50 mm (SD = 0.439) showed greater accuracy than the extender with 1.76 mm (SD = 0.525). The viscerocranial results for both splints were similar (extender 1.84 mm, SD = 0.559, rapid occlusal splint 1.86 mm, SD = 0.686). In the cranial vault region, registration with the extender (2.33 mm, SD = 0.685) proved to be more precise than with the rapid splint (2.86 mm, SD = 0.929). CONCLUSIONS: Due to the more compact dimension of the rapid occlusal splint, errors close to the splint were smaller compared to the extender technique. The advantage of greater distances between the registration fiducials on the extender is particularly important in areas such as the orbital roof, the cranial vault, and the lateral skull base.

[Facial pain- a rare cause. Impacted lower third molars causing primarily "unclear" facial pain: a case report]. / Gesichtsschmerzen - eine seltene Ursache. Retinierte untere Weisheitszahne als Ursache fur zunachst <> Gesichtsschmerzen. Ein Fallbericht.

Orofacial pain often causes special difficulties to patients and dentists. Numerous differential diagnoses require the utilization of a coordinated diagnostic concept. Often, multiple causes lead to the need for a complex treatment plan. Impacted third molars are a potential cause of a variety of complications. Caries, pulp necrosis, and periapical infection are some of the infrequent causes of such pain. The presented case shows just such a constellation, resulting in primarily "unclear" orofacial pain. A diagnostic sequence generally leads to the correct diagnosis and thereby allows for fast and effective therapy. This shows how important structured diagnostics are, especially in cases of "unclear" pain.

Bone regeneration by the osteoconductivity of porous titanium implants manufactured by selective laser melting: a histological and micro computed tomography study in the rabbit.

The treatment of large bone defects still poses a major challenge in orthopaedic and cranio-maxillofacial surgery. One possible solution could be the development of personalized porous titanium-based implants that are designed to meet all mechanical needs with a minimum amount of titanium and maximum osteopromotive properties so that it could be combined with growth factor-loaded hydrogels or cell constructs to realize advanced bone tissue engineering strategies. Such implants could prove useful for mandibular reconstruction, spinal fusion, the treatment of extended long bone defects, or to fill in gaps created on autograft harvesting. The aim of this study was to determine the mechanical properties and potential of bone formation of light weight implants generated by selective laser melting (SLM). We mainly focused on osteoconduction, as this is a key feature in bone healing and could serve as a back-up for osteoinduction and cell transplantation strategies. To that end, defined implants were produced by SLM, and their surfaces were left untreated, sandblasted, or sandblasted/acid etched. In vivo bone formation with the different implants was tested throughout calvarial defects in rabbits and compared with untreated defects. Analysis by micro computed tomography (µCT) and histomorphometry revealed that all generatively produced porous Ti structures were well osseointegrated into the surrounding bone. The histomorphometric analysis revealed that bone formation was significantly increased in all implant-treated groups compared with untreated defects and significantly increased in sand blasted implants compared with untreated ones. Bone bridging was significantly increased in sand blasted acid-etched scaffolds. Therefore, scaffolds manufactured by SLM should be surface treated. Bone augmentation beyond the original bone margins was only seen in implant-treated defects, indicating an osteoconductive potential of the implants that could be utilized clinically for bone augmentation purposes. Therefore, designed porous, lightweight structures have potential for bone regeneration and augmentation purposes, especially when complex and patient-specific geometries are essential.

[Infection after dental intervention. Iatrogenic or general medical cause? Case report]. / Infektion nach zahnärztlichem Eingriff. Zahnärztliche oder allgemeinmedizinische Ursache? Ein Fallbericht.

Whenever a dentist is dealing with abscess formation in the oral and maxillofacial region, it is mostly from dental origins. However, sometimes uncommon (co-)factors are present and responsible for major complications. Many general conditions or medications can significantly influence the course of an inflammation. It might spread faster and wider and also be resistant to "correct" therapy. This case report should raise awareness about general conditions supporting inflammation and demonstrate the importance of interdisciplinary treatment in these situations. A 76-year-old patient was referred to the maxillofacial surgery clinic after extraction of two teeth resulted in therapy-resistant painful swelling. Her dentist already had initiated "standard" therapy including Ponstan® (mefenamic acid) and Clamoxyl® (amoxicillin) without success. Initial blood testing came back with severe agranulocytosis. Immediately all potentially myelosuppressing drugs were stopped while myelosupporting drugs were prescribed. Under close interdisciplinary treatment conditions, healing was then uneventful without the necessity of surgical intervention. The challenge in inflammation treatment is to identify patients with uncommonly severe, fast-progressing, or therapy-resistant disease as early as possible. Further examination including blood workup for several medical parameters is indispensable in those patients.

[Risk assessment in patients undergoing osseous antiresorptive therapy in dentistry. An update]. / Risikobeurteilung von Patienten mit ossärer, antiresorptiver Therapie in der zahnärztlichen Praxis. Ein Update.

Antiresorptive therapy is prescribed in particular for the treatment of osteoporosis as well as for the treatment of tumor-induced hypercalcemia and metastatic bone disease. As a consequence, osteopathologies such as bisphosphonate-related osteonecrosis of the jaws (BRONJ) may occur. In 2008, our department reported on BRONJ in a paper that provided dental clinicians with information on diagnostics, therapy, and prevention (Dannemann et al., Schweizer Monatsschrift für Zahnmedizin, Vol. 118, 2/2008). During the last 8 years, new findings have emerged concerning potential etiologies, modes of therapy, and the use of additional antiresorptive therapies. For example, an important point for colleagues in dental practice is the now common intravenous administration of bisphosphonates in osteoporosis patients, which may lead to uncertainty when assessing risk in these patients. For this reason, this article provides an update of the above mentioned publication and gives dental clinicians an updated guideline concerning risk assessment in patients undergoing antiresorptive therapy. In this context, a risk assessment algorithm is presented. The pathogenesis, diagnosis, therapy, and prevention of BRONJ and oral implantation in patients receiving antiresorptive therapy are addressed with regard to the current literature. Finally, we present two example cases.

The Reliability of a Three-Dimensional Photo System- (3dMDface-) Based Evaluation of the Face in Cleft Lip Infants.

Ample data exists about the high precision of three-dimensional (3D) scanning devices and their data acquisition of the facial surface. However, a question remains regarding which facial landmarks are reliable if identified in 3D images taken under clinical circumstances. Sources of error to be addressed could be technical, user dependent, or patient respectively anatomy related. Based on clinical 3D photos taken with the 3dMDface system, the intra observer repeatability of 27 facial landmarks in six cleft lip (CL) infants and one non-CL infant was evaluated based on a total of over 1,100 measurements. Data acquisition was sometimes challenging but successful in all patients. The mean error was 0.86 mm, with a range of 0.39 mm (Exocanthion) to 2.21 mm (soft gonion). Typically, landmarks provided a small mean error but still showed quite a high variance in measurements, for example, exocanthion from 0.04 mm to 0.93 mm. Vice versa, relatively imprecise landmarks still provide accurate data regarding specific spatial planes. One must be aware of the fact that the degree of precision is dependent on landmarks and spatial planes in question. In clinical investigations, the degree of reliability for landmarks evaluated should be taken into account. Additional reliability can be achieved via multiple measuring.

[Late recurrence of keratocystic odontogenic tumor. A report of three cases]. / Spätrezidive beim keratozystischen odontogenen Tumor (KZOT). Ein Bericht über drei Patientenfälle.

BACKGROUND: Keratocystic odontogenic tumours (KCOT) are benign neoplasia of dentogenic origin and have a high relapse rate. Various invasive treatment methods (decompression, marsupialisation, enucleation, enucleation with adjunctive therapy such as scraping out of the bone cavity, Carnoy's solution or cryotherapy, mandibular resection) have been described for the treatment of KCOT. There is no common opinion on the best kind of treatment. Most of the articles in the literature report on a follow-up period of 5-7 years, but relapses have been described even after longer periods of time. This article presents 3 cases with late relapses that were treated at the University of Zurich, Center of Dental Medicine, Clinic of Cranio-Maxillofacial Surgery and Clinic for Oral Surgery. At the time of the initial diagnosis, the patients were 19, 24.5 and 36 years old. In all 3 patients the KCOT was localized in the angulus/ramus mandibula and an impacted wisdom tooth was present in the affected area. Case no. 1 was treated solely by marsupialisation of the KCOT. In cases no. 2 and 3, the cystic lesion was first marsupialised and later treated by enucleation and application of Carnoy's solution. In case no. 1, a relapse developed 13.5 years after the first operation. In case no. 2, relapses occurred 9, 28 and 31 years after the first operation. In case no. 3, a first relapse appeared 9 years and a second one 18 years after the first operation. CONCLUSION: Patients with a KCOT require lifelong aftercare because relapses of KCOTs can arise even after 10 or more years. The aftercare concept at the University of Zurich, Center of Dental Medicine, Clinic of Cranio-Maxillofacial Surgery and Clinic for Oral Surgery therefore consists of a clinical and x-ray (orthopantomogram) follow-up examination every year for the first 10 years and every two years thereafter.

Comparison of clonidine and midazolam as anxiolytic premedication before wisdom tooth surgery: a randomized, double-blind, crossover pilot study.

PURPOSE: Anxiolytic and possible side effects of clonidine 150 µg compared to midazolam 7.5 mg for premedication in surgical wisdom tooth extraction were evaluated. METHODS: In a prospective, randomized, double-blind crossover trial, ten patients undergoing bilateral wisdom tooth surgery received clonidine or midazolam orally 1 h before the treatment. Patients receiving midazolam for the first surgery received clonidine at the second surgery and vice versa. The anxiolytic efficacy was evaluated with a visual analogue scale (VAS) upon admission and 30, 50 and 60 min after administration of the medication. Patient satisfaction was recorded on a VAS after surgery and 7 days postoperatively. RESULTS: As soon as 30 min after administration of midazolam (p < 0.03) and clonidine (p < 0.02), an anxiolytic effect was recorded. Both medications did not differ in patient satisfaction. CONCLUSION: Oral administration of clonidine 150 µg and midazolam 7.5 mg were rated as medications with equal anxiolytic effects before wisdom tooth surgery under local anesthesia.

Point-to-point registration with mandibulo-maxillary splint in open and closed jaw position. Evaluation of registration accuracy for computer-aided surgery of the mandible.

INTRODUCTION: Computer navigation plays an increasingly important role in craniomaxillofacial surgery. The difficulties in computer navigation at the craniomaxillofacial site lie in the accurate transmission of the dataset to the operating room. This study investigates the accuracy of the dental-splint registration method for the skull, midface, and mandible. MATERIAL AND METHODS: A synthetic human skull model was prepared with landmarks and scanned with cone beam computer tomography (CBCT). Two registration splints fixed the mandible against the viscerocranium in two different positions (closed vs. open). The target registration error was computed in all 278 landmarks spread over the entire skull and mandible in 10 repeated measurements using the VectorVision(2) (BrainLAB Inc., Feldkirchen, Germany) navigation system. RESULTS: If registered in the closed position an average precision of 2.07 mm with a standard deviation (SD) of 0.78 mm was computed for all landmarks distributed over the whole skull. Registration in the open position resulted in an average precision of 1.53 mm (SD=0.55 mm). For single landmarks the precision decreases linearly with distance from the reference markers. The longer the three-dimensional distance between the registration points, the more precise the computer navigation is, mainly in the most posterior area of the cranium. CONCLUSION: Our findings in the cranium are comparable with those of other studies. Artificial fixation of the lower jaw via splint seems to introduce no additional error. The registration points should be as far apart from each other as possible during navigation with the splint.