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OBJECTIVES Human papillomavirus infection has been investigated intensively regarding oropharyngeal carcinoma. However, there is still lack of knowledge about the impact of oral HPV infections concerning oral squamous cell carcinoma. This study investigates the prevalence of oral HPV infection in such patients, identifying possible differences between HPV+ and HPV- patients. SUBJECTS AND METHODS One hundred and six consequent patients were investigated. After completion of a study questionnaire regarding risk factors, a brush smear sample was taken in each subject to identify the individual oral HPV status (overall/low risk/high risk). RESULTS About 35.8% of the patients were tested positive for HPV in the oral cavity (14% low risk, 28.3% high risk). Patients with oral HPV infection and high-risk HPV infection were significantly younger (p

In the past, maxillomandibular advancement has resulted in considerable improvement in the volume of the posterior airway space. The objective of the present study was to find out how mandibular advancement without maxillary involvement would affect the posterior airway space in patients with mandibular retrognathism. Cone-beam computed tomographic (CT) scans were done for 20 patients before, and six months after, mandibular advancement. Cephalometric analysis at both time points included 2-dimensional and 3-dimensional assessment of the upper airway. Eight men and 12 women presented a preoperative mean (SD) Wits value of 7.4 (1.54) mm, with an airway area of 7.11 (1.88) cm2 and a volume of 14.92 (4.46) cm3. Six months postoperatively they showed a Wits value of 2.7 (0.41) mm, an airway area of 11.33 (3.49) cm2, and a volume of 25.7 (6.10) cm3. There was a mean (range) enlargement of 59 (22-82) % of the area and 73 (29-108) % of the volume. A preoperative Wits value of 8mm or more correlated significantly with a larger increase of the posterior airway space (p=0.002). At the same time, an improvement in the Wits value of 4.5mm or more correlated significantly with an increase in volume (p=0.016). The effect of mandibular advancement on the posterior airway space was significant, and the volumetric effect seems to be even more relevant than the two-dimensional changes.

BACKGROUND AND PURPOSE: Dose reduction on CT scans for surgical planning and postoperative evaluation of midface and orbital fractures is an important concern. The purpose of this study was to evaluate the variability of various low-dose and iterative reconstruction techniques on the visualization of orbital soft tissues. MATERIALS AND METHODS: Contrast-to-noise ratios of the optic nerve and inferior rectus muscle and subjective scores of a human cadaver were calculated from CT with a reference dose protocol (CT dose index volume = 36.69 mGy) and a subsequent series of low-dose protocols (LDPs I–4: CT dose index volume = 4.18, 2.64, 0.99, and 0.53 mGy) with filtered back-projection (FBP) and adaptive statistical iterative reconstruction (ASIR)-50, ASIR-100, and model-based iterative reconstruction. The Dunn Multiple Comparison Test was used to compare each combination of protocols (α = .05). RESULTS: Compared with the reference dose protocol with FBP, the following statistically significant differences in contrast-to-noise ratios were shown (all, P ≤ .012) for the following: 1) optic nerve: LDP-I with FBP; LDP-II with FBP and ASIR-50; LDP-III with FBP, ASIR-50, and ASIR-100; and LDP-IV with FBP, ASIR-50, and ASIR-100; and 2) inferior rectus muscle: LDP-II with FBP, LDP-III with FBP and ASIR-50, and LDP-IV with FBP, ASIR-50, and ASIR-100. Model-based iterative reconstruction showed the best contrast-to-noise ratio in all images and provided similar subjective scores for LDP-II. ASIR-50 had no remarkable effect, and ASIR-100, a small effect on subjective scores. CONCLUSIONS: Compared with a reference dose protocol with FBP, model-based iterative reconstruction may show similar diagnostic visibility of orbital soft tissues at a CT dose index volume of 2.64 mGy. Low-dose technology and iterative reconstruction technology may redefine current reference dose levels in maxillofacial CT.

Purpose: Cone beam computed tomography (CBCT) is increasingly overtaking multislice computed tomography (MSCT) for implant planning and computer-aided design/computer-assisted manufacturing (CAD/CAM) surgical guide fabrication. The purpose of this study was to evaluate whether the image modality has a significant influence on the accuracy of image-fusion stereolithographic guides. Materials and Methods: A total of 240 implants were placed in 30 polymer models using surgical guides fabricated using CBCT or MSCT and optical scanning of dental casts and diagnostic wax-up. Postsurgical image data were fused with the planning data for evaluation of the following errors: total error (Euclidean error), mesiodistal and buccolingual error, depth error, and angular error. The CBCT and MSCT results were statistically compared using a t test (P = .05). Results: CBCT showed a statistically significantly higher total error with mean (± SD) of 0.36 ± 0.13 mm vs 0.27 ± 0.13 mm (P = .000), mesiodistal error with 0.20 ± 0.14 mm vs 0.16 ± 0.11 mm (P = .018), and depth error with 0.17 ± 0.12 mm vs 0.07 ± 0.07 mm (P = .000). Buccolingual and angular errors did not statistically significantly differ with 0.16 ± 0.11 mm vs 0.15 ± 0.12 mm (P = .613), and 0.96 ± 0.47 degrees vs 0.85 ± 0.59 degrees (P = .111). Conclusion: Using CBCT for image-fusion stereolithographic guides may provide lower accuracy than MSCT. The results should be confirmed on alternative CBCT scanners. Due to the total volume of tissues, image artifacts, and patient movements, the advantages seen using MSCT on models could be nonexistent or exacerbated on patients. Patient studies are required to demonstrate clinical relevance.

Objective To assess the linear measurements of edentulous ridges recorded from multidetector row computed tomography (MDCT) images obtained by a previously untested ultra-low dose in combination with filtered back-projection (FBP), adaptive statistical iterative reconstruction (ASIR), and model-based iterative reconstruction (MBIR). Methods Three cadavers were imaged using a reference protocol with a standard dose and FBP (volume CT dose index (CTDIvol): 29.4 mGy) and two ultra-low-dose protocols, LD1 and LD2 (CTDIvol: 0.53 and 0.29 mGy). All test examinations were reconstructed with FBP, ASIR 50, ASIR 100, and MBIR. Linear measurements from the images of the edentulous ridges recorded from the test protocols were compared with those from the reference using a one-sample t test, Bland–Altman plots, and linear regression. Statistical significance was set at a p value of 0.05. Results The one-sample t test demonstrated a statistically significant difference between the measurements from the reference protocol and all test protocols. The difference was not clinically significant for the following three test protocols: LD1/FBP, LD1/ASIR 50, and LD2/FBP. Bland–Altman plots with linear regression showed no systematic variation between the measurements obtained with the reference protocol and these three test protocols. Conclusions The lowest-dose protocol to demonstrate comparable measurements with a standard MDCT dose was CTDIvol 0.29 mGy with FBP. These results must be considered with caution for areas of the jaws with thin cortication. The results in areas of thin cortication should be verified by studies with larger sample sizes at such areas and comparison with true gold standard measurements. Electronic supplementary material The online version of this article (10.1007/s11282-018-0350-z) contains supplementary material, which is available to authorized users.

Objectives: To compare subjective and objective localization of the inferior alveolar canal (IAC) on multidetector CT (MDCT) images obtained by ultralow doses in combination with the reconstruction techniques of filtered backprojection (FBP), adaptive statistical iterative reconstruction (ASIR), or model-based iterative reconstruction (MBIR) as compared to standard dose MDCT and FBP. Methods: Three cadavers were imaged with a reference standard dose MDCT examination (volume CT dose index: 29.4 mGy) reconstructed with FBP and 5 low dose protocols (LD1-5) (volumeCT dose index: 4.19, 2.64, 0.99, 0.53, 0.29 mGy) reconstructed with FBP, ASIR 50, ASIR 100, and MBIR. Linear measurements from the crest of the ridge to the roof of the IAC were recorded. The results from the test protocols were compared with those from the reference using Bland–Altman plots. Results: Only three test protocols allowed the identification of the position of the IAC on all the sample sites: LD1/FBP and LD1/ASIR 100 and LD2/FBP. All three protocols allowed identification of the IAC with comparable results to the reference dose protocol; the 95% confidence interval limits for the measurement differences were ± 0.41 mm, but the differences were not statistically significant. The calculated effective dose for the LD2 protocol, for a scan length of 5 cm, was 27.7 µSv. Conclusions: Using FBP, comparable IAC measurements were achieved with 91% reduction in dose compared with a standard exposure protocol. The use of ASIR and MBIR did not improve identification of the IAC in MDCT low dose images.

Different authors hypothesized an important impact of sexual behavior on the prevalence of oral human papillomavirus (HPV) infections. In order to investigate this relationship more in detail and in contrast to most other studies, the present work focused on the population group with the highest risk for sexually transmitted infections: young and sexual active adults. Three hundred and ten men and women aged 18–30 years could be recruited. After the completion of a risk-factor survey, brush smear samples for oral HPV detection were taken in every participant. In 18.1 %, oral HPV could be detected. Overall, smoking (p = 0.0074) and a high number of different sexual partners (vaginal: p = 0.0001; oral: p

The influence of dose reductions on diagnostic quality using a series of high-resolution ultralow-dose computed tomography (CT) scans for computer-assisted planning and surgery including the most recent iterative reconstruction algorithms was evaluated and compared with the fracture detectability of a standard cranial emergency protocol. A human cadaver head including the mandible was artificially prepared with midfacial and orbital fractures and scanned using a 64-multislice CT scanner. The CT dose index volume (CTDIvol) and effective doses were calculated using application software. Noise was evaluated as the standard deviation in Hounsfield units within an identical region of interest in the posterior fossa. Diagnostic quality was assessed by consensus reading of a craniomaxillofacial surgeon and radiologist. Compared with the emergency protocol at CTDIvol 35.3 mGy and effective dose 3.6 mSv, low-dose protocols down to CTDIvol 1.0 mGy and 0.1 mSv (97% dose reduction) may be sufficient for the diagnosis of dislocated craniofacial fractures. Non-dislocated fractures may be detected at CTDIvol 2.6 mGy and 0.3 mSv (93% dose reduction). Adaptive statistical iterative reconstruction (ASIR) 50 and 100 reduced average noise by 30% and 56%, and model-based iterative reconstruction (MBIR) by 93%. However, the detection rate of fractures could not be improved due to smoothing effects.

Objective The role of human papilloma virus (HPV) infections in oral carcinogenesis is an important topic of research in maxillofacial oncology. Nevertheless, the association between such infections in the oral cavity and the development of oral precancerous lesions remains unclear. The aim of this study was to evaluate the association between oral HPV infections and oral leukoplakia or erythroplakia. Study Design The case control study included 118 patients with manifest oral leukoplakia or erythroplakia, who underwent surgical biopsy, including a histopathologic grading of the lesion, and 100 control patients without any oral lesions. HPV detection was achieved with a noninvasive brush smear method (Digene Cervical Sampler, Hybrid Capture II-Test). Logistic regression analysis was performed to assess the associations. Results A significant association was found between high-risk oral HPV infection and the presence of oral premalignant lesions (P = .001). Among all other evaluated parameters, only smoking showed a significant association with the presence of oral lesions. Conclusions Oral HPV infections may play a role in the pathogenesis of premalignant oral lesions.

OBJECTIVE. The purpose of this article is to evaluate 2D and 3D image quality of high-resolution ultralow-dose CT images of the craniofacial bone for navigated surgery using adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) in comparison with standard filtered backprojection (FBP). MATERIALS AND METHODS. A formalin-fixed human cadaver head was scanned using a clinical reference protocol at a CT dose index volume of 30.48 mGy and a series of five ultralow-dose protocols at 3.48, 2.19, 0.82, 0.44, and 0.22 mGy using FBP and ASIR at 50% (ASIR-50), ASIR at 100% (ASIR-100), and MBIR. Blinded 2D axial and 3D volume-rendered images were compared with each other by three readers using top-down scoring. Scores were analyzed per protocol or dose and reconstruction. All images were compared with the FBP reference at 30.48 mGy. A nonparametric Mann-Whitney U test was used. Statistical significance was set at p0.05. RESULTS. For 2D images, the FBP reference at 30.48 mGy did not statistically significantly differ from ASIR-100 at 3.48 mGy, ASIR-100 at 2.19 mGy, and MBIR at 0.82 mGy. MBIR at 2.19 and 3.48 mGy scored statistically significantly better than the FBP reference (p = 0.032 and 0.001, respectively). For 3D images, the FBP reference at 30.48 mGy did not statistically significantly differ from all reconstructions at 3.48 mGy; FBP and ASIR-100 at 2.19 mGy; FBP, ASIR-100, and MBIR at 0.82 mGy; MBIR at 0.44 mGy; and MBIR at 0.22 mGy. CONCLUSION. MBIR (2D and 3D) and ASIR-100 (2D) may significantly improve subjective image quality of ultralow-dose images and may allow more than 90% dose reductions.

To compare the surface of computer-aided design (CAD) models of the maxilla produced using ultra-low MDCT doses combined with filtered backprojection (FBP), adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) reconstruction techniques with that produced from a standard dose/FBP protocol. A cadaveric completely edentulous maxilla was imaged using a standard dose protocol (CTDIvol: 29.4 mGy) and FBP, in addition to 5 low dose test protocols (LD1-5) (CTDIvol: 4.19, 2.64, 0.99, 0.53, and 0.29 mGy) reconstructed with FBP, ASIR 50, ASIR 100, and MBIR. A CAD model from each test protocol was superimposed onto the reference model using the ‘Best Fit Alignment’ function. Differences between the test and reference models were analyzed as maximum and mean deviations, and root-mean-square of the deviations, and color-coded models were obtained which demonstrated the location, magnitude and direction of the deviations. Based upon the magnitude, size, and distribution of areas of deviations, CAD models from the following protocols were comparable to the reference model: FBP/LD1; ASIR 50/LD1 and LD2; ASIR 100/LD1, LD2, and LD3; MBIR/LD1. The following protocols demonstrated deviations mostly between 1–2 mm or under 1 mm but over large areas, and so their effect on surgical guide accuracy is questionable: FBP/LD2; MBIR/LD2, LD3, LD4, and LD5. The following protocols demonstrated large deviations over large areas and therefore were not comparable to the reference model: FBP/LD3, LD4, and LD5; ASIR 50/LD3, LD4, and LD5; ASIR 100/LD4, and LD5. When MDCT is used for CAD models of the jaws, dose reductions of 86% may be possible with FBP, 91% with ASIR 50, and 97% with ASIR 100. Analysis of the stability and accuracy of CAD/CAM surgical guides as directly related to the jaws is needed to confirm the results.

Various risk factors for oral human papillomavirus (HPV) infections have been described, including tobacco smoking and sexual behavior. However, less is known about the influence of oral health on such infections. The present study aimed to determine a possible association between the quality of oral hygiene and the presence of oral HPV.In a prospective analysis, the approximal plaque index (API), the gingival bleeding index (GBI), and the lifetime number of extracted teeth was determined in 187 patients. Additionally, the presence of oral low-risk and/or high-risk HPV was investigated by brush smear testing in all participants.Seventy-four patients had an API 20%, 84 participants showed an API of 20-40%, and in 29 cases, an API 40% was recorded. Ninety-six patients presented a GBI 20%, 75 had a GBI of 20-40%, and 16 showed a GBI 40%. One hundred four patients had experienced one to three extractions, and 36 had lost more than three teeth. Thirty-nine participants had a positive oral HPV testing (27 high-risk HPV, 26 low-risk HPV, 14 low- and high-risk HPV). A higher API respectively GBI and a greater number of extracted teeth were significantly correlated with the presence of high-risk HPV. The presence of low-risk HPV was significantly higher in patients with API 40% and GBI 40% (OR 7.89). Similar results were found regarding the number of extracted teeth.The present analysis confirms a relationship between the quality of oral hygiene, determined by objective markers. Thus, improvement of oral health may reduce the incidence of oral HPV infection.The present article investigates the relationship between oral hygiene and the presence of oral HPV. As a significant correlation between these two factors could be recorded, improvement of oral hygiene may reduce actively the incidence of oral HPV. Thereby, good oral hygiene may contribute oral cancer prevention.

The objective of this study was to determine how iterative reconstruction technology (IRT) influences contrast and spatial resolution in ultralow-dose dentomaxillofacial CT imaging.A polymethyl methacrylate phantom with various inserts was scanned using a reference protocol (RP) at CT dose index volume 36.56 mGy, a sinus protocol at 18.28 mGy and ultralow-dose protocols (LD) at 4.17 mGy, 2.36 mGy, 0.99 mGy and 0.53 mGy. All data sets were reconstructed using filtered back projection (FBP) and the following IRTs: adaptive statistical iterative reconstructions (ASIRs) (ASIR-50, ASIR-100) and model-based iterative reconstruction (MBIR). Inserts containing line-pair patterns and contrast detail patterns for three different materials were scored by three observers. Observer agreement was analyzed using Cohen's kappa and difference in performance between the protocols and reconstruction was analyzed with Dunn's test at α = 0.05.Interobserver agreement was acceptable with a mean kappa value of 0.59. Compared with the RP using FBP, similar scores were achieved at 2.36 mGy using MBIR. MIBR reconstructions showed the highest noise suppression as well as good contrast even at the lowest doses. Overall, ASIR reconstructions did not outperform FBP.LD and MBIR at a dose reduction of90% may show no significant differences in spatial and contrast resolution compared with an RP and FBP. Ultralow-dose CT and IRT should be further explored in clinical studies.

Humane Papillomaviren (HPVs) gelten als kausale Ursache bei der Entstehung maligner Tumore. Die vorliegende Untersuchung bewertet die Anwendung der in der Gynakologie als Routineverfahren verwendeten HPV-Abstrichmethode (Digene Cervical Sampler®) im Rahmen der oralen HPV-Diagnostik. Es wird die Methodik des Verfahrens beschrieben, Reliabilitatsbestimmungen und Fehlermoglichkeiten bewertet und die Studienergebnisse mit Ergebnissen der aktuellen Literatur verglichen. Die Digene Cervical Sampler HC2 Hybrid Capture®-Diagnostik (Digene Cervical Sampler® in Kombination mit Hybrid Capture II® Assay) stellt ein zuverlassiges und kostengunstiges Verfahren in der oralen high-risk- und low-risk-HPV-Diagnostik dar.

Purpose: Reduction of the radiation exposure involved in image-guided craniofacial and skull base surgery is an important goal. The purpose was to evaluate the influence of low-dose protocols in modern multi-slice spiral computed tomography (MSCT) on target registration errors (TREs). Materials and Methods: An anthropomorphic skull phantom with target markers at the craniofacial bone and the anterior skull base was scanned in Sensation Open (40-slice), LightSpeed VCT (64-slice) and Definition Flash (128-slice). Identical baseline protocols (BP) at 120 kV/100 mAs were compared to the following low-dose protocols (LD) in care dose/dose modulation: (LD-I) 100 kV/35ref. mAs, (LD-II) 80 kV/40 – 41ref. mAs, and (LD-III) 80 kV/15 – 17ref. mAs. CTDIvol and DLP were obtained. TREs using an optical navigation system were calculated for all scanners and protocols. Results were statistically analyzed in SPSS and compared for significant differences (p ≤ 0.05). Results: CTDIvol for the Sensation Open/LightSpeed VCT/Definition Flash showed: (BP) 22.24 /32.48 /14.32 mGy; (LD-I) 4.61 /3.52 /1,62 mGy; (LD-II) 3.15 /2.01 /0.87 mGy; and (LD-III) na/0.76 /0.76 mGy. Differences between the BfS (Bundesamt fur Strahlenschutz) reference CTDIvol of 9 mGy and the lowest CTDIvol were approximately 3-fold for Sensation Open, and 12-fold for the LightSpeed VCT and Definition Flash. A total of 33 registrations and 297 TRE measurements were performed. In all MSCT scanners, the TREs did not significantly differ between the low-dose and the baseline protocols. Conclusion: Low-dose protocols in modern MSCT provided substantial dose reductions without significant influence on TRE and should be strongly considered in image-guided surgery.

The primary malignant melanoma is a rare neoplasm of melanocytic origin in the oral cavity. Only about 1% of all melanomas arise in the oral mucosa and these account for 0.5% of all oral malignancies This report describes an oral malignant melanoma occurring in the right maxilla of a 73-year-old patient. The interdisciplinary management using a nasolabial flap and prosthetic oral rehabilitation procedure is described. The nasolabial flap technique offers the possibility of an immediate reconstruction of the maxillary defect and obviated problems with speech, swallowing, and permitted oral intake. As a supplementary benefit, the resection area can support the prosthetic rehabilitation.

Purpose In computer-assisted implantation surgery, the transfer of prosthodontic-guided planning to the operative site is usually based on a registration template. The precise repositioning of the registration template is crucial for high accuracy and is compromised in edentulous jaws. The purpose was to determine the in vitro registration and targeting accuracy for surgical navigation in the edentulous jaw based on 3 fixed intraoral reference points. Materials and Methods Edentulous maxilla and mandible cadaver specimens were provided with 3 fixed reference-point screws. A resin template with matrices for the fixed reference-point screws was produced and connected to a Vogele-Bale-Hohner registration mouthpiece and external registration frame with a snap-lock system. Surgical implants were planned on computed tomographic data and the corresponding dental stone casts were drilled under guidance of an optical navigation system. For evaluation of the registration accuracy, fiducial registration error was recorded and application accuracy was evaluated by fusion of postsurgical computed tomographic scans of the drilled dental stone casts with the presurgical planning computed tomogram. Results In 9 maxillas and 5 mandibles, 14 registrations and 104 stone cast drillings were performed. The mean fiducial registration error was 0.49 ± 0.14 mm (0.37 to 0.9 mm). The mean total error at the tip of the borehole was 0.88 ± 0.65 mm (0.0 to 4.24 mm). The mean lateral errors were 0.51 ± 0.49 mm (0.0 to 2.80 mm) at the base and 0.46 ± 0.34 mm (0.0 to 1.5 mm) at the tip of the borehole, respectively. The mean angular error was 0.83 ± 0.60° (0.0 to 2.5°). Conclusion Three fixed intraoral reference points successfully support a registration mouthpiece and provide in vitro registration and targeting accuracy that is comparable to tooth-supported registration templates or bone marker registration.

A newborn female was referred with the following clinical symptoms: median tongue cleft, palate cleft, ankyloglosson, sublingual intraoral hamartoma and palatal intraoral hamartoma. Magnetic resonance imaging showed a subcutaneous cyst overlying the manubrium sterni. Genetic investigation (chromosome analysis) showed no aberrations and/or variations. The quick growth of the intraoral hamartoma required an excision at the age of 3 months. Under general anaesthesia the intraoral hamartoma was excised and the median tongue cleft was closed. Median tongue clefts are reported to be only associated with orofacial digital syndromes type I, II, IV and VI. If the clinical appearance is described without any association to an orofacial syndrome, the Tessier 30 cleft definition could be used as the best explanation of the symptoms. This is the first description of a combination of tongue cleft, palate cleft, intraoral hamartoma and subcutaneous cyst overlying the manubrium sterni. The clinical symptoms of this patient can be described best as a mild form of an orofacial digital syndrome type II or variation of a Tessier cleft No. 30.

Computer-assisted implant surgery usually requires a radiographic scan template as the basis for prosthetic-driven implant planning and surgical guide fabrication.The study aims to evaluate the accuracy of image-fusion stereolithographic guides in which a computed tomography (CT) scan is mapped with three-dimensional optical scans of cast and diagnostic wax-up.Three-dimensional error at the base and tip of the implants, angular deviation of the implant-axis, and the inserting-depth error of 120 implants with a length of 10 mm and a caliber of 4.1 mm in 15 polymer-models were examined. A control CT was performed and fused with the planning data for accuracy evaluation.The mean three-dimensional error was 0.21 ± 0.10 mm (0.00-0.48 mm) at the implant base, 0.32 ± 0.17 mm (0.03-0.75 mm) at the implant tip, and the mean angular error was 0.85 ± 0.59° (0.00-2.50°). The mean depth error was 0.07 ± 0.07 mm (0.00-0.32 mm).Within the limitations of an in vitro study, the novel technique showed excellent accuracy. Errors from fabrication and scanning of a radiographic scan template can be avoided, and the workflow and costs of computer-assisted implant surgery may be reduced.

Teratocarcinosarcoma (TCS) is a very rare and aggressive neoplasm characterized by teratoma and carcinosarcoma components. The authors report on a case of TCS in the oral cavity of a child. Rapid growth and extensive local destruction were prominent features prior to treatment. Histologic examination revealed various tissue elements, such as epithelial, mesenchymal, and neuroectodermal components. Chemotherapy was effective in reducing tumor mass, followed by partial anterior mandibulectomy and reconstruction with composite microvascular tissue transfer. The approach allowed radical resection of the tumor and functional reconstruction with excellent aesthetic results.

Objective Different modalities have been described regarding the treatment of mandibular condyle fractures. The most advantageous and safest one is still a topic of discussion. The present analysis describes the combination of a retromandibular, transparotideal approach combined to a triangular-positioned double-miniplate osteosynthesis, with a special regard for the patients' long term outcomes. Material and methods Clinical data of 102 patients with 124 condyle fractures treated with the mentioned surgical procedure were evaluated. Functional parameters such as the maximal interincisal distance, deviations/deflections, facial nerve function, occlusion as well as complications regarding the parotid gland, osteosynthesis, and esthetics were evaluated 1 week, 2 weeks, 3 months, and 6 months postoperatively. Results The mean maximal interincisal distance ranged from 38 mm after 1 week to 45 mm after 6 months. Deviations/deflections were seen in 22.5% of the cases 1 week postoperatively and decreased to 2% at 6 months postoperatively. A temporary facial palsy was diagnosed in 3.9% during the first follow-up, whereas no impairment was recorded after 3 or 6 months. At the same time, no patient had occlusional disturbances or complications regarding the parotid gland or the osteosynthesis 6 months postoperatively. Conclusions Direct fracture visualization and a stable three-dimensional fracture stabilization are the main advantages of the presented combination of a surgical approach and osteosynthesis technique. Additionally, the absence of long-term complications confirms the safety of the procedure. Therefore, it may be considered as a successful treatment option for mandibular condyle fractures.

Summary Although there have been recent advances in maxillofacial surgery and anaesthetic techniques, blood replacement is still common in orthognathic surgery. 179 patients underwent elective orthognathic surgery and donated autologous blood preoperatively. Standardized questionnaires about the preoperative blood donation were distributed to the patients. Haemoglobin, haematocrit, red blood cells and platelets were measured before blood donation, presurgically and postsurgically, as well as one year after surgery. Nearly all patients (98%) would recommend preoperative autologous blood donation. 97% of the patients saw the benefits of autologous blood donation in avoiding transfusion-transmitted infectious diseases such as acquired immune deficiency syndrome (AIDS) and hepatitis. No serious side-effects have been observed after blood donation. In patients with bimaxillary osteotomies (65% of the predeposited autologous blood units) 41% were in cases having upper jaw osteotomies and only 22% of the preoperatively donated units were retransfused in patients having lower jaw osteotomies. After a postsurgical decrease, the mean haemoglobin and mean haematocrit levels regained the levels determined prior to the donation. Preoperative autologous blood donation of 2 to 3 units (900–1350 ml ± 10%) of blood is recommended in bimaxillary osteotomies and 1 to 2 units (450–900 ml ± 10%) of blood for upper jaw osteotomies. In lower jaw surgery, the acute isovolaemic haemodilution should be considered.

The aim of this study was to evaluate whether application of ultralow dose protocols and iterative reconstruction technology (IRT) influence quantitative Hounsfield units (HUs) and contrast-to-noise ratio (CNR) in dentomaxillofacial CT imaging.A phantom with inserts of five types of materials was scanned using protocols for (a) a clinical reference for navigated surgery (CT dose index volume 36.58 mGy), (b) low-dose sinus imaging (18.28 mGy) and (c) four ultralow dose imaging (4.14, 2.63, 0.99 and 0.53 mGy). All images were reconstructed using: (i) filtered back projection (FBP); (ii) IRT: adaptive statistical iterative reconstruction-50 (ASIR-50), ASIR-100 and model-based iterative reconstruction (MBIR); and (iii) standard (std) and bone kernel. Mean HU, CNR and average HU error after recalibration were determined. Each combination of protocols was compared using Friedman analysis of variance, followed by Dunn's multiple comparison test.Pearson's sample correlation coefficients were all0.99. Ultralow dose protocols using FBP showed errors of up to 273 HU. Std kernels had less HU variability than bone kernels. MBIR reduced the error value for the lowest dose protocol to 138 HU and retained the highest relative CNR. ASIR could not demonstrate significant advantages over FBP.Considering a potential dose reduction as low as 1.5% of a std protocol, ultralow dose protocols and IRT should be further tested for clinical dentomaxillofacial CT imaging.HU as a surrogate for bone density may vary significantly in CT ultralow dose imaging. However, use of std kernels and MBIR technology reduce HU error values and may retain the highest CNR.

This case report presents the surgical and restorative management of a fused supernumerary left lateral incisor. The diagnosis was confirmed using conventional radiographs and CT. The case report discusses the value of CT for evaluation of the root relationships and describes the varied morphology associated with supernumerary incisors, the surgical resection technique, partial pulpotomy, and restoration with composite resin after mechanical exposure of the remaining tooth's pulp.

Cone-beam computed tomography (CBCT) is increasingly used in craniofacial imaging and may be an interesting option for navigated surgery. The purpose of this study was to evaluate the accuracy of various registration techniques in CBCT compared with intraoperative and diagnostic multislice spiral computed tomography (MSCT).High-resolution images of an anthropomorphic skull phantom with target markers were obtained using 2 CBCT machines (KaVo 3D eXam, ILUMA), an intraoperative MSCT (Sensation Open), and the standard diagnostic MSCT (LightSpeed VCT). Bone markers, a registration template, and an external registration frame were used for registration with an optical-based navigation system. Target registration errors (TREs) were evaluated and statistically analyzed in SPSS (P.05).The mean ± standard deviation for overall TREs of the KaVo 3D eXam, ILUMA, Sensation Open, and LightSpeed VCT devices were 1.37 ± 0.54, 1.67 ± 0.65, 1.27 ± 0.52, and 1.31 ± 0.30 mm, respectively. The KaVo 3D eXam showed no significant differences compared with the MSCTs. The ILUMA imaged the external registration frame only marginally and showed significant higher TREs compared with the other registration methods (P.001). In the 2 MSCTs, no significant differences between the registration methods were found.CBCT and intraoperative MSCT may show comparable TREs as standard diagnostic MSCT. Bone markers are the gold standard. Registration templates and external registration frames are valuable alternatives. When using only external registration frames, CBCTs with a large scan field are recommended.

Registration refers to the linkage of coordinates from an image with actual patient coordinates and has been shown to be the most influential factor in the accuracy of image-guided surgery. Invasive bone markers are the gold standard but require surgical placement prior to imaging. In contrast, registration templates or external registration frames are noninvasive, but their repositioning during imaging and surgery can be a source of error. The purpose of the present study was to determine whether noninvasive registration methods can achieve an accuracy similar to that of invasive bone marker registration.Computed tomographic slices (1 mm each) of a maxillary and mandibular dental stone cast that had been prepared with target markers on the buccal and oral surfaces were registered with an optical-based navigation system simulating invasive bone markers, noninvasive registration templates, and a noninvasive external registration frame. Predicted error of the navigation system, fiducial registration error, and target registration error were evaluated. The use of five and seven registration markers was compared.A total of 696 error measurements was performed. The external registration frame showed significantly worse fiducial registration error compared with the other methods, but there was no significant difference in target registration error between invasive and noninvasive registration methods. The predicted error given by the navigation system significantly underestimated target registration error. Increasing the number of registration markers from five to seven resulted in no significant differences.Noninvasive registration based on registration templates or external registration frames showed accuracy that was equivalent to that of invasive registration. The use of five registration markers was sufficient. The predicted error given by a navigation system should not be mistaken as "navigation error" during clinical application.

Objectives In edentulous patients, accurate and stable positioning of a surgical template is impeded by the mobile mucosal tissue. The objective was to evaluate the accuracy of flapless computer-assisted template-guided surgery in an edentulous human cadaver specimen using three fixed oral reference points (FRP) for fixation of the registration mouthpiece and the consecutive surgical template. Material and methods Oral implants were planned on the computed tomography (CT) of an edentulous human cadaver specimen. Surgical templates have been fabricated using a multipurpose navigation system. Both the registration mouthpiece and consecutive surgical template were supported via three FRP. Study implants were inserted through the guide sleeves and the accuracy was evaluated on a post-surgical CT of the cadaver jaws fused with the pre-surgical planning CT. A Matlab script enabled comparison of the planned surgical path with the study implants. Results In five maxillary and three mandibular edentulous human cadaver specimens, a total of 51 implants (35 implants in the maxilla and 16 implants in the mandible) have been placed. The mean+/-standard deviation total error (Euclidean distance)/lateral error (normal deviation) were 1.1+/-0.6/0.7+/-0.5 mm at the implant base and 1.2+/-0.7/0.9+/-0.7 mm at the implant tip. The mean angular error was 2.8+/-2.2 degrees. Conclusions Flapless surgery based on FRP-supported image-guided surgical templates may provide similar accuracy as reported for tooth-supported surgical templates or surgical navigation.

Navigated oral implant surgery requires knowledge and skills in computed tomography (CT) imaging, three-dimensional (3D) planning, and use of surgical navigation systems. To improve teaching and training, a laboratory training and evaluation technique has been developed.The technique uses a surgical navigation system, a dental dummy and anonymous data of previously treated patients, including duplicated dental stone casts, individualized registration mouthpieces and CT scans. Training consists of definition of the prosthetic goal, 3D planning and navigated model surgery. For evaluation, a post-surgical CT of the drilled dental stone casts is fused with the original planning CT.Each step of navigated implant surgery can be simulated and trained. Post-surgical evaluation includes Euclidean distance, normal distance, angular deviations and damage to critical anatomical structures, such as nerves and sinuses.The presented technique allows for successful laboratory training and evaluation of computer-aided oral implant surgery.

Purpose We present a concept that uses the multipurpose navigation equipment of a university hospital for computed tomography (CT)-guided surgical template production, to improve the preclinical accuracy of the templates. Materials and Methods Oral implants are planned on CT images with respect to the prosthodontic goal and anatomical considerations. Registration is performed via a modified Vogele-Bale-Hohner (VBH) mouthpiece (Medical Intelligence GmbH, Schwabmuenchen, Germany) and an external registration frame. In the laboratory, an optical navigation system is used to transfer the plan to the patient's registered dental stone cast for surgical template production. During preclinical evaluation, duplicated stone casts were drilled via the obtained surgical templates. Accuracy was evaluated by matching the preoperative CT to the CT of the drilled stone casts. Results Compared with present registration mouthpieces, the VBH mouthpiece requires only the dental impression of the patient's stone cast. In contrast to surgical navigation, an aiming device is used for navigated trajectory-alignment at the best technical level. There is no need for a positioning device, and the template can be immediately fabricated in a standard laboratory. The accuracy of 5 surgical templates showed a maximum normal deviation of 1.4 mm, and maximum angular deviations of 2.8°. Conclusion The presented concept allows for successful production of CT-guided surgical templates, and may show sufficient accuracy for clinical use.

The iliac crest is among the most frequent sites for free vascularized bone donation. However, donor site morbidity is often marked with persistent pain, abnormal sensation, abdominal herniation, musculoskeletal imbalance and a disfigured appearance. The authors present a technique of reconstructing the bony gap after iliac crest harvest by inserting a metal plate. Apart from restoration of the iliac contour after skin closure, the plate enables fixation of the transected abdominal wall muscles. This results in less postoperative pain and shorter rehabilitation, as well as an improved musculoskeletal balance and a reduced risk of abdominal wall herniation.

Objective : To test the effectiveness of the new technique of tissue-engineered growth of cartilage, temporomandibular joint (TMJ) disc replacements were created by seeding dissociated chondrocytes on synthetic, three-dimensional, bioresorbable polymer constructs of a predetermined anatomic shape, incubating the cell-polymer constructs in vitro, and transplanting them into test animals. Materials and Methods : Twelve highly porous and bioresorbable cell-transplantation devices in the shape of TMJ discs were created using biodegradable polylactid and polyglycolic acid fibers. Bovine articular cartilage was dissociated into chondrocytes and the cells were allowed to attach to the three-dimensional polymer scaffolds and multiply in vitro. After 1 week, the cell-polymer constructs were implanted subcutaneously into nude mice. The neocartilage was assessed by magnetic resonance imaging (MRI) techniques, gross inspection, histology, and biomechanical and biochemical analysis after 12 weeks. Results : All implants seeded with chondrocytes showed gross evidence of histologically organized hyaline cartilage. The scaffolds maintained their specific shape. They not only showed appropriate intrinsic stability during neomorphogenesis of cartilage in vitro and in vivo, but also seemed to guide the growth of cartilage. The presence of sulfated glycosaminoglycans was shown by aldehyde fuchsin alcian blue staining of the specimens. Type II collagen, considered to be indicative of cartilage formation, was found in the specimens tested. MRI showed signal characteristics similar to those of hyaline cartilage. Analysis of neocartilage force/displacement curves and aqueous phase compliance using a closed compression chamber suggested that the ability of the constructs to resist deformation was similar to that of native donor cartilage. Conclusion : The technology of tissue-engineered growth of cartilage on individually designed scaffolds may have many applications not only in reconstructive surgery of the TMJ, but also in craniomaxillofacial, plastic, and orthopedic surgery.