A new standardized critical size bone defect model in the pig forehead for comparative testing of bone regeneration materials.

OBJECTIVES: The preclinical study aimed to establish a standardized preclinical model to investigate osseous graft consolidation in defect configurations of limited regenerative capacity. MATERIAL AND METHODS: Critical size defects (CSD) were prepared and titanium tubes inserted for defect separation from local bone in the forehead area of 18 pigs. Defects were filled with demineralized bovine bone mineral (DBBM) or served as empty controls and were covered with a resorbable collagen membrane (CM) or left untreated. Six randomly selected pigs were sacrificed after 4, 8 and 12 weeks. Specimens were histologically and histomorphometrically analysed focusing on newly formed bone (NFB), demineralized bovine bone mineral (DBBM) and soft tissue (ST) proportions. RESULTS: Four weeks after defect preparation, no statistically significant difference concerning NFB quantity could be detected within the groups. Defects covered with the CM showed lower amounts of DBBM. After 6 and 12 weeks, defects augmented with DBBM in combination with a CM (8 weeks: 43.12 ± 4.31; 12 weeks: 43.05 ± 3.01) showed a statistically significant higher NFB rate compared to empty control defects covered with 8 weeks: 7.66 ± 0.59; 12 weeks or without a CM; 8 weeks: 8.62 ± 2.66; 12 weeks: 18.40 ± 2.40. CM application showed no significant impact on osseous defect regeneration or soft tissue formation. Superior NFB could be detected for basal aspect for several evaluation time points. CONCLUSIONS: The modification of CSD with titanium tubes represents a suitable model to imitate a one-wall defect regeneration situation. CLINICAL RELEVANCE: The established model represents a promising method to evaluate graft consolidation in one-wall defect configuration.

Panoramic radiograph, computed tomography or magnetic resonance imaging. Which imaging technique should be preferred in bisphosphonate-associated osteonecrosis of the jaw? A prospective clinical study.

It was the aim of the present study to find out which radiological imaging techniques allow assessing the extent of bisphosphonate-associated osteonecrosis of the jaw (BONJ) in an adequate way. Twenty-four patients suffering from BONJ were included in the study. Before surgery, each patient was examined with panoramic radiograph, contrast-enhanced magnetic resonance imaging (MRI) and non-enhanced computed tomography. The detectability of BONJ was assessed for the three imaging techniques. The extent of the jaw region affected by BONJ was determined in MRI and CT scans and compared to the intra-operative situation. The detectability of BONJ lesions was 54% for panoramic radiographs, 92% for MRI scans and 96% for computed tomography (CT) scans. The intra-operatively assessed extent of BONJ correlated significantly with the measurements on CT scans (p = 0.0004) but did not correlate significantly with the measurements in MRI scans (p = 0.241). The intra-operatively measured extent of BONJ differed significantly from the CT measurements (p = 0.00003) but not from the MRI data (p = 0.137). Although MRI as well as CT have a high detectability for BONJ lesions that exceeds that of panoramic radiographs by far, both techniques show problems with the exact assessment of the extent of BONJ lesions in the individual patients. Therefore, the relevance of MRI and CT for the preoperative assessment of the extent of BONJ lesions is limited. Future research should focus on the identification of imaging techniques that allow assessing the extent of BONJ lesions with a higher accuracy.

Prosthodontic treatment of a patient with bisphosphonate-induced osteonecrosis of the jaw using a removable dental prosthesis with a heat-polymerized resilient liner: a clinical report.

Bisphosphonate-induced osteonecrosis of the jaws (BONJ) is reported frequently in patients receiving oral or intravenous bisphosphonates. To minimize potential complications, dental treatment must be performed with care. There are invasive and noninvasive treatment options for patients with active BONJ or a history of this complication. This clinical report describes the prosthodontic treatment of a patient who developed BONJ after receiving intravenous bisphosphonates (pamidronate). Because of the recurrent incidence of BONJ, noninvasive prosthetic therapy with telescopic overdentures and a heat-polymerized resilient liner was provided. After 2 years, there were no biological or technical complications.

Which region of the median palate is a suitable location of temporary orthodontic anchorage devices? A histomorphometric study on human cadavers aged 15-20 years.

INTRODUCTION: Endosseus implants can provide a reliable anchorage during orthodontic treatment. The midpalatal structures around the sutura palatina mediana (SPM) are of special interest due to increasing placement of orthodontic implants in this area. Knowledge about the osseous conditions at this site is necessary to predict the expected degree of implant osseointegration. METHODS: The upper jaws of 10 human cadavers, aged 15-20 years, were decalcified, and cross-sectional specimens were obtained from four anterior-to-posterior palatal regions for histomorphometric analysis. The analyses focused on the amount of bone and the width of the SPM to determine the anatomical requirements for reliable insertion of palatal implants. RESULTS: Bone density [bone-volume (BV)/ tissue-volume (TV)] in all measured areas was 40-60%. The maximum density was measured at the level of the first premolars (54.9+/-5.9%) and the least values (44.2+/-9.6%) were measured at the level of the interconnecting line of the canines. The mean width of the SPM varies from 1.2 to 0.3 mm in different sections of the palate. In the median sagittal plane, the mean values of bone height to nasal cavity reached >5 mm as far as the level distal of the second premolars. Bone height 2 mm paramedian to the SPM decreased consistently from anterior (4.3+/-0.9 mm) to posterior (2.5+/-0.8 mm). CONCLUSIONS: Our results indicate that the amount and quality of bone along the anterior palatal midline in 15-to-20-year olds is sufficient for orthodontic implantation. Even implantation posterior to the recommended first premolar level, at which orthodontic implants are most often placed, may be suitable. There are some limitations, however, due to small number of samples and variations of anatomical structures.

Influence of residual alveolar bone height on osseointegration of implants in the maxilla: a pilot study.

AIMS/BACKGROUND: For sinus floor augmentation and simultaneous implant placement, a minimum of 5 mm of residual bone height has been recommended empirically. This study was designed to test this assumption in an experimental animal trial. MATERIAL AND METHODS: In eight mini pigs, three premolars and two molars were removed on one side of the maxilla. Three months later, the animals were assigned to four groups of two animals each. A cavity was created at the base of the alveolar process so that the residual bone height was reduced to 2, 4, 6 and 8 mm, respectively. Six implants were installed and an inlay augmentation procedure was carried out using a particulated iliac bone graft. Implants were loaded with fixed provisional restorations after a healing period of 6 months. The animals were sacrificed after 6 months of functional loading. Histologic specimens were prepared and histomorphometric analysis was performed [bone-to-implant contact (BIC) ratio, interthread bone area, peri-implant bone area, crestal bone resorption (CBR)]. RESULTS: Two implants were lost during follow-up and fibrous encapsulation was detected in one additional implant. All failures occurred in one animal with a residual alveolar height of 2 mm. On the buccal aspect, BIC turned out to be significantly higher for 6 mm when compared with 2/4 mm (75.8 +/- 26.1 vs. 58 +/- 23.2/53.9 +/- 22.8; P<0.05), while on the palatal aspect, BIC was significantly higher for 6/8 mm when compared with 2/4 mm (80 +/- 17.8/78.9 +/- 10.3 vs. 55.8 +/- 26.5/55.6 +/- 21.3; P<0.05). For an alveolar height of 8 mm, CBR tended to be significantly lower than for bone heights of 2/4 mm (3.8 +/- 2.3 vs. 5.3 +/- 2.6/5.8 +/- 3.9; P<0.05). Correlation analysis revealed a significant association of BIC and interthread bone area as well as a negative association to CBR on the palatal aspect. CONCLUSION: The results of the present study show that the combination of maxillary inlay grafting and simultaneous implant placement does not hinder osseous integration even though the alveolar crest has been reduced to a residual height of 4 mm and below. However, according to histomorphometry, the highest predictability is gained in sites with residual bone heights of 6 and 8 mm.

Influence of residual alveolar bone height on implant stability in the maxilla: an experimental animal study.

AIMS/BACKGROUND: Empirically, for implant placement associated with sinus floor augmentation, a minimum of five mm of residual crestal bone height has been recommended in order to achieve sufficient initial implant stability. It has been the aim of the study to test this assumption in an experimental animal trial. MATERIAL AND METHODS: In eight mini pigs, three premolars and two molars were removed on one side of the maxilla. Three months later the animals were assigned to four groups of two animals each. A cavity was created at the base of the alveolar process so that the residual bone height was reduced to 2, 4, 6 and 8mm, respectively. The coronal part of the alveolar crest remained unchanged. An inlay augmentation procedure was carried out using a particulated autogenous bone graft from the iliac crest, and six implants (Xive, diameter 3.8mm, length 13mm) were placed. Implant stability was assessed by resonance frequency analysis at the time of implant placement (T0), after 6 months of unloaded healing (T1) and after 6 months of functional loading (T2). RESULTS: During follow-up, two implants were lost in sites with a residual alveolar bone height of 2mm. At the time of implant placement, resonance frequencies were 6754.4 +/- 268, 6500.3 +/- 281.5, 6890.3 +/- 255.4 and 7877.9 +/- 233.7 Hz for residual bone heights of 2, 4, 6 and 8mm, respectively. At stage-two surgery and after 6 months of functional loading, resonance frequencies were 6431.7 +/- 290.8, 6351.8 +/- 437.6, 6213.4 +/- 376.2 and 6826.8 +/- 458.9 Hz vs. 6171 +/- 437.4, 6047 +/- 572.4, 6156.7 +/- 272.6 and 6412.8 +/- 283.5 Hz. Statistical analysis revealed an association of residual alveolar height and implant stability at T0 and T1 only (P<0.01), while bone height was not found to influence implant survival. CONCLUSION: The results of the present trial demonstrate an association of alveolar bone height and implant stability at the time of implant placement and stage-two surgery. Yet the assumption that 5mm of residual crestal bone height is a relevant threshold for simultaneous implant placement and sinus floor augmentation is not supported from an experimental point of view.

Indications for immediate loading of implants and implant success.

It was the aim of this review to compare the survival and success rates of immediately loaded dental implants with those of conventionally loaded dental implants, based on prospective controlled studies and prospective studies without controls. Studies on immediate loading were identified in the current literature by electronic and hand searches. Only clinical data on root-form or cylindrical threaded oral implants were included. For immediate loading of oral implants in the edentulous and partially dentate, mandible and maxilla controlled studies could be found. All of these studies were based on limited patient numbers. Therefore, definitive conclusions could not be drawn concerning survival and success rates of immediately loaded implants compared with conventionally loaded implants. The compilation of the current literature shows that prospective controlled studies as well as prospective studies without controls using several different approaches to immediate loading have demonstrated high implant survival and success rates. However, more high-level evidence-based studies are needed to demonstrate the relative merits of immediate loading compared with conventional loading in all potential applications.

Tunable Graphene-GaSe Dual Heterojunction Device.

A field-effect device based on dual graphene-GaSe heterojunctions is demonstrated. Monolayer graphene is used as electrodes on a GaSe channel to form two opposing Schottky diodes controllable by local top gates. The device exhibits strong rectification with tunable threshold voltage. Detailed theoretical modeling is used to explain the device operation and to distinguish the differences compared to a single diode.

Immediate versus delayed loading of dental implants in the maxillae of minipigs. Part II: histomorphometric analysis.

PURPOSE: To assess histomorphometric parameters of dental implants placed in partially edentulous maxillae of minipigs. MATERIALS AND METHODS: In 9 minipigs, 6 XiVE implants were placed on each side of the maxilla, either after implant site preparation by an osteotome technique or by spiral drills. The implants were restored with fixed provisional restorations and loaded either immediately or after healing periods of up to 5 months. After a loading period of 6 months, the animals were sacrificed and the implants were retrieved together with the adjacent bone. Histologic specimens were prepared and bone-to-implant contact (BIC) ratio, interthread bone area, and peri-implant bone area were determined. RESULTS: An analysis of variance revealed that the BIC ratio on the palatal side was significantly influenced by the preparation technique of the implant site (P = .001) and by the healing period (P = .02). After implant site preparation by an osteotome technique, higher BIC values were achieved for implants that were loaded either immediately or after healing periods of 1 to 3 months. After healing periods of 4 to 5 months, implant site preparation with spiral drills showed slightly better results in regard to BIC. Interthread bone area and peri-implant bone area did not differ significantly statistically for the 2 implant placement techniques and the 3 healing periods. DISCUSSION AND CONCLUSION: After 6 months of functional loading in the maxilla, successful immediately loaded implants performed the same as implants subjected to an unloaded healing period prior to loading as far as histomorphometric data were concerned. Prospective randomized clinical studies should be carried out in humans to compare immediate loading to loading after an unloaded healing phase.

Immediate versus delayed loading of dental implants in the maxillae of minipigs: follow-up of implant stability and implant failures.

PURPOSE: To assess the course of the stability and the failure rate of dental implants placed in the partially edentulous maxillae of minipigs. MATERIALS AND METHODS: Three months after tooth removal, implants were placed in 9 minipigs. Six implants (XiVE; Friadent, Mannheim, Germany) were placed on each side of the posterior maxilla after preparation of the implant sites either by an osteotome technique or with spiral drills. Implant stability was assessed by resonance frequency analysis (RFA) at the time of placement, at second-stage surgery (which took place after a healing periods of 1, 2, 3, 4, or 5 months), and after a loading period of 6 months. RESULTS: Implant stability was significantly influenced by the healing period (P = .007). Implant stability decreased after 1 to 3 months of healing for both of the placement techniques and increased after a healing period of 4 months. After implant site preparation by an osteotome technique, 6 of 12 immediately loaded implants, 18 of 24 implants loaded after healing periods of 1 to 3 months, and 1 of 18 implants loaded after a healing period of 4 or 5 months were lost. After implant site preparation using spiral drills, 7 of 12 immediately loaded implants, 12 of 24 implants loaded after healing periods of 1 to 3 months, and 2 of 18 implants loaded after healing periods of 4 or 5 months were lost. Broad overlapping of confidence intervals for the number of implant failures revealed that there was no relevant difference between immediate and early functional loading for either of the 2 techniques. DISCUSSION AND CONCLUSION: Implant loading after healing periods of 1 to 3 months did not improve implant survival compared to immediate loading in the posterior maxillae of minipigs. Not until a healing period of 4 months was reached did implant stability begin to increase. Only when functional loading was started at this point in time was maximal implant survival achieved.

Probing resistivity and doping concentration of semiconductors at the nanoscale using scanning microwave microscopy.

We present a new method to extract resistivity and doping concentration of semiconductor materials from Scanning Microwave Microscopy (SMM) S11 reflection measurements. Using a three error parameters de-embedding workflow, the S11 raw data are converted into calibrated capacitance and resistance images where no calibration sample is required. The SMM capacitance and resistance values were measured at 18 GHz and ranged from 0 to 100 aF and from 0 to 1 MΩ, respectively. A tip-sample analytical model that includes tip radius, microwave penetration skin depth, and semiconductor depletion layer width has been applied to extract resistivity and doping concentration from the calibrated SMM resistance. The method has been tested on two doped silicon samples and in both cases the resistivity and doping concentration are in quantitative agreement with the data-sheet values over a range of 10(-3)Ω cm to 10(1)Ω cm, and 10(14) atoms per cm(3) to 10(20) atoms per cm(3), respectively. The measured dopant density values, with related uncertainties, are [1.1 ± 0.6] × 10(18) atoms per cm(3), [2.2 ± 0.4] × 10(17) atoms per cm(3), [4.5 ± 0.2] × 10(16) atoms per cm(3), [4.5 ± 1.3] × 10(15) atoms per cm(3), [4.5 ± 1.7] × 10(14) atoms per cm(3). The method does not require sample treatment like cleavage and cross-sectioning, and high contact imaging forces are not necessary, thus it is easily applicable to various semiconductor and materials science investigations.

Geographic differences and time trends of intraoral cancer incidence and mortality in Bavaria, Germany.

OBJECTIVE: To examine possible geographic differences and time trends of intraoral cancer (IOC) incidence and mortality in Bavaria between 2002 and 2008. METHODS: Incidence data for IOC (ICD-10 codes, C01-C06) were obtained from the population-based cancer registry Bavaria. Age-specific and age-standardised IOC incidence and mortality rates in Bavaria and its regions were calculated separately by sex and year of diagnosis. RESULTS: We found an excess incidence of 34% and 25% among men and women in Upper Franconia compared to Bavaria. Incidence and mortality related to IOC in Bavaria are comparable to those found in other European cancer registries. IOC mortality appears to decrease over time in both sexes, whereas IOC incidence appears to decrease only in men. CONCLUSIONS: The observed geographic differences with respect to IOC incidence and mortality in Bavaria may possibly be explained in part by socioeconomic differences.

Validation of histologic changes induced by external irradiation in mandibular bone. An experimental animal model.

The present experimental study sought to determine the effect of high-dose irradiation on the rat mandible in order to establish an experimental model of radiogenic bone damage. The left mandibles of 20 adult Wistar rats were irradiated (single fraction 1500cGy, total dose 60Gy) by means of a hypofractionated stereotactic radiotherapy (hfSRT) over a period of 6 weeks. Follow-up was 6 weeks (group 1, n=10) and 12 weeks (group 2, n=10). The contralateral mandibles as well as 5 non-irradiated animals served as controls. Primary endpoints were fibrosis, loss of cell count, decreased immunohistochemical labelling for bone morphogenetic protein-2 (BMP-2) and osteocalcin as well as increased expression of transforming growth factor (TGF-beta). Cell loss, progressive fibrosis, and focal necrosis were detected in all irradiated sites. Quantitative measurement revealed 32.0+/-8.7% and 37.3+/-9.5% empty osteocyte lacunae for groups 1 and 2 resp., compared to 16.3+/-4.7% and 18.9+/-4.9% on the contralateral side and 7.9+/-1.7% for unirradiated controls (Mann-Whitney U test; p<.01). BMP-2 and osteocalcin labelling showed a marked decrease in irradiated and contralateral sides while TGF-beta was expressed strongly in irradiated sites only (for all p<.05). External hypofractionated irradiation with a total dose of 60Gy is feasible in rats and yields all histologic changes attributed to osteoradionecrosis (ORN) after a follow-up of 6 weeks. The irradiation protocol is suitable for an assessment of regenerative options in severe radiogenic bone damage. As a split mouth design entails major inaccuracies healthy animals have to be used as controls.

Vertical and sagittal growth in patients with unilateral and bilateral cleft lip and palate-a retrospective cephalometric evaluation.

OBJECTIVE: To investigate whether the craniofacial vertical and sagittal jaw relationship in patients with cleft lip and palate (CLP) differed from that of age-matched noncleft controls, before and after the pubertal growth spurt. DESIGN: Retrospective observational study. PATIENTS: The study group comprised 126 patients with CLP, subdivided according to gender and cleft type, and the control group comprised 53 age-matched skeletal class I patients. METHODS: Angular and linear measurements were taken from prepubertal and postpubertal lateral cephalograms of all patients. RESULTS: In patients with cleft lip and palate, the maxillary retrognathism became more remarkable with increasing age; whereas, the retrognathic position of the mandible became less pronounced as compared with controls. Reduced posterior midfacial height, a common prepubertal finding in patients with cleft lip and palate, was significant in postpubertal girls and young women with unilateral cleft lip and palate (p = .002). The total anterior facial height in male patients with bilateral cleft lip and palate was larger than in control patients (p = .002) after the pubertal growth spurt due to an increased anterior midfacial height. In male patients with unilateral cleft lip and palate, this finding was due to an increased anterior lower facial height (p < .001). CONCLUSIONS: Patients with cleft lip and palate treated according to a standardized treatment concept had adequate craniofacial jaw relationships after puberty. Despite a measured skeletal class I in both male and female patients with cleft lip and palate regardless of cleft type, there was a slight tendency toward a skeletal class III. Findings were similar for all groups of cleft lip and palate patients irrespective of the type of orthodontic treatment performed.

Prognostic impact of blood transfusion in patients undergoing primary surgery and free-flap reconstruction for oral squamous cell carcinoma.

BACKGROUND: The objective of this study was to assess the impact of perioperative transfusion on the prognosis of patients who underwent complete (R0) resection of oral squamous cell carcinoma and reconstruction by microvascular flaps. METHODS: By following an inclusion and exclusion protocol, 223 patients were included in the study who underwent R0 resection of oral squamous cell carcinoma and reconstruction by microvascular flaps at a single center. Clinical and pathologic factors as well as transfusion data were retrieved from a prospective database and analyzed retrospectively. Survival data were assessed using the method of Kaplan and Meier. For multivariate analysis the accelerated failure time model (Weibull distribution) was chosen. RESULTS: The overall survival rate was 71% at 1 year, 67% at 3 years, and 55% at 5 years. In univariate analysis, age (P = .003), tumor size (P = .005), lymph node status (P = .008), tumor differentiation (P = .008), transfusion (P = .006), American Society of Anesthesiologists (ASA) class (P = .001), and mandibular reconstruction (P = .045) were associated significantly with overall survival. Multivariate analysis identified only age, histopathologic differentiation, and ASA class as independent risk factors (P < .001, P = .04, and P = .049, respectively). Age was identified as the strongest independent predictor for overall survival (hazards ratio for each 13-year increase in age, 1.97; 95% confidence interval, 1.36-2.85). CONCLUSIONS: Transfusion of >4 U of blood did not appear to influence overall survival in patients who underwent primary surgery for oral squamous cell carcinoma. Because age and ASA class evolved as the strongest predictors of shortened overall survival, associated comorbidities may require more attention, particularly in elderly or socially deprived patients.

Interforaminal implant therapy using a split skin graft--treatment outcome after 13 years.

In implant patients who have extended soft tissue deficiencies, split skin grafts have been performed for the prevention of peri-implant inflammation. The aim of this investigation was to assess a patient who received 2 interforaminal implants and a split skin graft 13 years prior. In addition to clinical, mycologic, and radiographic examinations, the condition of the split skin graft was evaluated using histologic analysis of 3 punch biopsies taken from the mucosa, grafted area, and border between both areas. The implants were found to have an overall good clinical condition. Fungal infection was not present. The histologic analysis revealed inflammation-free mucosal and submucosal tissue in all samples. In the area of the skin graft, the mucosa was not keratinized and showed an increased thickness of the submucosal connective tissue. For the patient under examination, an acceptable level of oral rehabilitation was achieved using a split skin graft. The follow-up investigation showed stable conditions for both the implants and the graft.

Blood transfusion in bimaxillary orthognathic operations: need for testing of type and screen.

We prospectively evaluated the incidence of blood transfusion in 105 consecutively treated patients (45 men and 60 women) having bimaxillary orthognathic operations, to find out whether type and screen testing are adequate in clinical practice. All patients had Le Fort I osteotomy combined with bilateral sagittal split osteotomy of the ramus. The preoperative routine was restricted to type and screen testing and verification of ABO/Rhesus (Rh) status. Autologous blood donation or routine cross-matching of allogeneic units of blood was not done. Intraoperative haemoglobin concentrations and the need for blood transfusion in patients having bimaxillary osteotomies were recorded in a prospective database. The mean duration of operation was 196 min (range 115-325). The median length of hospital stay was 8 days (range 4-16). The mean (SD) reduction in haemoglobin during operation was 34 (16)g/L in men and 32 (10)g/L in women (p=0.32). No patients had an allogeneic blood transfusion. We found that type and screen testing and verification of ABO/Rh status seems to be an adequate precaution to manage blood loss. As reflected by the low rate of transfusion in the present study, severe haemorrhage that requires transfusion of allogeneic blood has become the exception rather than the rule in bimaxillary orthognathic operations.

[Clinical and radiological results after augmentation procedures - a prospective study]. / Klinische und radiologische Ergebnisse nach Augmentationen - eine prospektive Evaluation.

The clinical follow up of atrophic jaws treated with augmentation procedures and dental implants is demonstrated and evaluated over a period of five years. In total 50 patients (24 male and 26 female) from the department of maxillofacial surgery of the Friedrich Alexander University Erlangen-Nuernberg who received an augmentation procedure were prospectively evaluated. The mean age was 59.1 years on the female and 56.9 years on the male patients. All patients received prior to implant placement an augmentation with autogenous bone or a bone substitute and were reconstructed using a fixed or removable implant borne rehabilitation. Overall 293 implants from five different systems were used, 10 implants on eight patients were lost in the observation period. Three implants were lost during the healing period and seven after prosthetic rehabilitation. This leads to a cumulative survival rate of 96.6%. The success rate, according to the criterions defined by Karoussis et al. [25] was 94.04%. After twelve months in the area of augmentation an overall resorption rate of 26.4 % was found, at five years the rate mounted to 31.67%. Comparing the resorption rates in maxilla and mandible the vertical loss was 35.88%, rsp. 26,05%. Comaring the posterior and anterior augmentation areas the vertical loss was significantly (p: 0.048%) higher in the posterior with 38.72% compared to 28.26% in the anterior region. Measurement of the SFFR (sulcus fluid flow rate) demonstrated a significant (P. 0.03) correlation with bone resorption, meaning that higher SFF rates showed higher rates of vertical resorption. Additionally a high SFF rate correlated with higher pocket depths and reduced keratinized periimplant gingival rates.

Conventional radiographs: are they still the standard in localization of projectiles?

The penetration of air gun pellets in facial soft tissue can cause major problems during the removal of foreign bodies, although conventional radiography, computed tomography, image-guided surgical removal, and ultrasound have been applied to facilitate the procedure. It was the aim of the present case report to introduce a modified intraoperative method for the localization of air gun pellets, based on the use of radiopaque markers in conventional radiographs. A 66-year-old patient attempted to commit suicide by using an air gun. The pellet hit the right temporal region. A computed tomographic (CT) scan was acquired to localize the foreign body. The first attempt to remove the pellet through the penetrating wound failed. Because of a dislodgement of the pellet, the CT scan could no longer be used for the localization of the air gun pellet. As the air gun pellet was positioned under the zygomatic arch, ultrasound was unable to identify its position. Successful intraoperative localization of the projectile was performed after fixation of radiopaque markers to the skin in the region of the estimated localization, with conventional radiographs in 2 planes, acquired with a mobile dental x-ray device. Although the markers remained attached to the patient as reference makers, the air gun pellet was removed easily. The use of radiopaque markers in conventional radiographs in 2 planes allows fast, intraoperative localization of radiopaque foreign bodies within soft tissue. The procedure can be carried out with a conventional x-ray device that should be available in every oral and maxillofacial practice. The use of reference markers should be considered a standard procedure for the localization of radiopaque foreign bodies in the head and neck.

Patient-centred outcomes comparing transmucosal implant placement with an open approach in the maxilla: a prospective, non-randomized pilot study.

It was the aim of the study to assess differences in patient morbidity between transmucosal implant placement and implant installation after elevation of mucoperiosteal flaps. In five of the patients, implants were placed in the maxilla transmucosally using a CAD/CAM surgical template [test group (TG)]. In the remaining five patients, the implants were installed after the elevation of mucoperiosteal flaps [control group (CG)]. Directly after surgery, at days 1 and 7 after surgery the patients rated pain and discomfort on a visual analogue scale (0=minimal pain and discomfort, 100=maximal pain and discomfort). Optical three-dimensional images were assessed preoperatively and at days 1 and 7 after surgery to determine the visible soft tissue swelling of the upper lip and cheeks. Directly postoperatively, the mean pairwise difference between both groups in view of pain and discomfort ratings (control minus test) was 45.6 (SD, 20.7). At days 1 and 7, the mean differences were 51.6 (SD, 21.8) and 19 (SD, 8), respectively. The overall test of the area under curve (AUC) against the null hypothesis 'AUC of pairwise differences of pain score over study time equals null' yielded a significant difference (P=0.01). The mean pairwise difference between both groups in view of soft tissue volume increase was 6.1 (SD, 2) cm(3) at day 1 after surgery and 4.6 (SD, 1.2) cm(3) at day 7. The overall test of the AUC against the null hypothesis 'AUC of pairwise differences of oedema measurements over study time equals null' yielded a significant difference (P=0.002). Within the limitations of this pilot study, it could be shown that transmucosal implant placement reduces patient morbidity significantly compared with an open approach.