Accuracy of maxillary positioning using computer-designed and manufactured occlusal splints or patient-specific implants in orthognathic surgery.

OBJECTIVE: To determine the accuracy of maxillary positioning using computer-designed and manufactured occlusal splints or patient-specific implants in orthognathic surgery. MATERIAL AND METHODS: A retrospective analysis of 28 patients that underwent virtually planned orthognathic surgery with maxillary Le Fort I osteotomy either using VSP-generated splints (n = 13) or patient-specific implants (PSI) (n = 15) was conducted. The accuracy and surgical outcome of both techniques were compared by superimposing preoperative surgical planning with postoperative CT scans and measurement of translational and rotational deviation for each patient. RESULTS: The 3D global geometric deviation between the planned position and the postoperative outcome was 0.60 mm (95%-CI 0.46-0.74, range 0.32-1.11 mm) for patients with PSI and 0.86 mm (95%-CI 0.44-1.28, range 0.09-2.60 mm) for patients with surgical splints. Postoperative differences for absolute and signed single linear deviations between planned and postoperative position were a little higher regarding the x-axis and pitch but lower regarding the y- and z-axis as well as yaw and roll for PSI compared to surgical splints. There were no significant differences regarding global geometric deviation, absolute and signed linear deviations in the x-, y-, and z-axis, and rotations (yaw, pitch, and roll) between both groups. CONCLUSIONS: Regarding accuracy for positioning of maxillary segments after Le Fort I osteotomy in orthognathic surgery patient-specific implants and surgical splints provide equivalent high accuracy. CLINICAL RELEVANCE: Patient-specific implants for maxillary positioning and fixation facilitate the concept of splintless orthognathic surgery and can be reliably used in clinical routines.

Evaluation of 3D MRI for early detection of bone edema associated with apical periodontitis.

OBJECTIVES: To detect and evaluate early signs of apical periodontitis using MRI based on a 3D short-tau-inversion-recovery (STIR) sequence compared to conventional panoramic radiography (OPT) and periapical radiographs in patients with apical periodontitis. MATERIALS AND METHODS: Patients with clinical evidence of periodontal disease were enrolled prospectively and received OPT as well as MRI of the viscerocranium including a 3D-STIR sequence. The MRI sequences were assessed for the occurrence and extent of bone changes associated with apical periodontitis including bone edema, periradicular cysts, and dental granulomas. OPTs and intraoral periapical radiographs, if available, were assessed for corresponding periapical radiolucencies using the periapical index (PAI). RESULTS: In total, 232 teeth of 37 patients (mean age 62±13.9 years, 18 women) were assessed. In 69 cases reactive bone edema was detected on MRI with corresponding radiolucency according to OPT. In 105 cases edema was detected without corresponding radiolucency on OPT. The overall extent of edema measured on MRI was significantly larger compared to the radiolucency on OPT (mean: STIR 2.4±1.4 mm, dental radiograph 1.3±1.2 mm, OPT 0.8±1.1 mm, P=0.01). The overall PAI score was significantly higher on MRI compared to OPT (mean PAI: STIR 1.9±0.7, dental radiograph 1.3±0.5, OPT 1.2±0.7, P=0.02). CONCLUSION: Early detection and assessment of bone changes of apical periodontitis using MRI was feasible while the extent of bone edema measured on MRI exceeded the radiolucencies measured on OPT. CLINICAL RELEVANCE: In clinical routine, dental MRI might be useful for early detection and assessment of apical periodontitis before irreversible bone loss is detected on conventional panoramic and intraoral periapical radiographs.

Chronic Periodontal Infection and Not Iatrogenic Interference Is the Trigger of Medication-Related Osteonecrosis of the Jaw: Insights from a Large Animal Study (PerioBRONJ Pig Model).

Background and Objectives: Antiresorptive drugs are widely used in osteology and oncology. An important adverse effect of these drugs is medication-induced osteonecrosis of the jaw (MRONJ). There is scientific uncertainty about the underlying pathomechanism of MRONJ. A promising theory suspects infectious stimuli and local acidification with adverse effects on osteoclastic activity as crucial steps of MRONJ etiology. Clinical evidence showing a direct association between MRONJ and oral infections, such as periodontitis, without preceding surgical interventions is limited. Large animal models investigating the relationship between periodontitis and MRONJ have not been implemented. It is unclear whether the presence of infectious processes without surgical manipulation can trigger MRONJ. The following research question was formulated: is there a link between chronic oral infectious processes (periodontitis) and the occurrence of MRONJ in the absence of oral surgical procedures? Materials and Methods: A minipig large animal model for bisphosphonate-related ONJ (BRONJ) using 16 Göttingen minipigs divided into 2 groups (intervention/control) was designed and implemented. The intervention group included animals receiving i.v. bisphosphonates (zoledronate, n = 8, 0.05 mg/kg/week: ZOL group). The control group received no antiresorptive drug (n = 8: NON-ZOL group). Periodontitis lesions were induced by established procedures after 3 months of pretreatment (for the maxilla: the creation of an artificial gingival crevice and placement of a periodontal silk suture; for the mandible: the placement of a periodontal silk suture only). The outcomes were evaluated clinically and radiologically for 3 months postoperatively. After euthanasia a detailed histological evaluation was performed. Results: Periodontitis lesions could be induced successfully in all animals (both ZOL and NON-ZOL animals). MRONJ lesions of various stages developed around all periodontitis induction sites in the ZOL animals. The presence of MRONJ and periodontitis was proven clinically, radiologically and histologically. Conclusions: The results of this study provide further evidence that the infectious processes without prior dentoalveolar surgical interventions can trigger MRONJ. Therefore, iatrogenic disruption of the oral mucosa cannot be the decisive step in the pathogenesis of MRONJ.

MRI of the inferior alveolar nerve and lingual nerve-anatomical variation and morphometric benchmark values of nerve diameters in healthy subjects.

OBJECTIVE: Since MRI using dedicated imaging sequences has recently shown promising results in direct visualization of the inferior alveolar nerve (IAN) and the lingual nerve (LN) with high spatial resolution, the aim of this study was to generate suitable standard specifications to reliably depict the IAN and LN in MRI and to delineate the anatomy and its variants of these nerves in healthy subjects. METHODS: Thirty healthy volunteers were examined on a 3-T scanner (Elition, Philips Healthcare, Best, the Netherlands). The sequence protocol consisted of 3D STIR, 3D DESS, and 3D T1 FFE "black bone" sequences. RESULTS: The study reconfirmed a good feasibility of direct visualization of proximal and peripheral portions of the IAN and of the proximal course of the LN. The STIR sequence showed the highest apparent signal to noise ratio (aSNR) and best apparent nerve-muscle contrast to noise ratio (aNMCNR) for IAN and for the LN. The applied MRI sequences allowed to differentiate the tissue composition of the neurovascular bundle inside the mandibular canal. CONCLUSION: Dedicated MRI sequence protocols proved effectively to detect the IAN and LN and their course in healthy volunteers. The tissue composition of the mandibular neurovascular bundle was conclusively distinguishable as was the varying topography inside multiple bony channels. CLINICAL RELEVANCE: The presented data on the precise and valid visualization of the IAN and LN have clinical implications in respect to local anesthesia prior to dental treatments in the mandible but also regarding surgical procedures and implant insertion in the molar region.

Long-Term Efficacy of Variable-Thread Tapered Implants-A Retrospective, Clinical and Radiological Evaluation.

Background and Objective: There is multifaceted evidence that variable-thread tapered implants (VTTIs) offer high primary stability but few regarding the long-term success. This retrospective clinical and radiological cohort study assessed the long-term outcome of VTTIs. Material and Methods: All patients treated in an OMFS practice with NobelActive Internal® VTTI between October 2007 and September 2011 were invited for clinical examination. The outcome variables were (i) survival rate, (ii) implant success according to the "Health Scale for Dental Implants" and (iii) prevalence of peri-implantitis. Furthermore, the effect of local and systemic risk factors was investigated. Results: In 81 subjects (46 females and 35 males, mean age 65.6 years) 270 implants (157 VTTIs and 113 others as a control group) were analyzed. In 7 out of 81 patients (8.6%), 8 out of 157 VTTIs (5.1%) and 5 out of 113 other implants (4.4%) were lost. Peri-implantitis, defined as (i) presence of bleeding on gentle probing (0.25 N) or exudation and (ii) radiographic bone loss exceeding 0.5 mm since implant insertion to last follow-up, was the most common reason for implant loss (11 out of 13, 84.6%). Sixty-six out of 87 VTTIs (75.9%) were successful. Seventeen out of 42 patients (40.5%) developed peri-implantitis on 29 out of 79 VTTI sites (36.7%). Plaque and missing keratinized peri-implant mucosa were identified as potential risk factors for the development of peri-implantitis. Conclusion: Variable-thread tapered implants showed good long-term results, even in low bone quality. Peri-implantitis was the most common reason for implant failure and may be connected to certain risk factors.

What Factors Are Associated With Regional Recurrence After Operative Treatment of Oral Squamous Cell Carcinoma?

PURPOSE: A considerable proportion of oral squamous cell carcinoma (OSCC) recurrences involve the neck, which has a substantial impact on prognosis and is poorly understood. The purpose of this study was to analyze clinical and pathologic characteristics of regional recurrence of OSCC and identify possible risk factors. MATERIALS AND METHODS: A single-center retrospective cohort study was designed to address the study purpose. All patients who were treated surgically for primary OSCC with or without adjuvant therapy between 2010 and 2015 were considered for inclusion with respect to predefined criteria, and demographic, clinical, and pathologic variables were collected. The lymph node status after primary OSCC treatment (pN) was defined as the predictor variable, and the occurrence of regional recurrence served as the primary outcome variable. Further variables of special interest were the histologic differentiation (G status) of the primary OSCC and the values of the lymph node ratio and log odds of positive lymph nodes. Descriptive, inferential, and appropriate time-dependent (Kaplan-Meier analysis, Cox regression model) statistics were computed. The level of statistical significance was set at P ≤ .05. RESULTS: The study sample was composed of 171 patients (70 women and 101 men; average age, 62.4 years). Neck failure occurred in 18 patients (11%) either in combination with local recurrence (15 patients) or in isolation (3 patients). Poor histologic differentiation of the primary tumor was identified as an independent risk factor for regional recurrence. Most neck recurrences manifested in previously unaddressed levels (IV and V). CONCLUSIONS: Regional recurrence of OSCC might be associated with specific clinicopathologic parameters of the primary tumor. The importance of these parameters for OSCC prognosis assessment and recurrence prediction should be elucidated in further studies.

Fully automatic CAD design of the occlusal morphology of partial crowns compared to dental technicians' design.

OBJECTIVES: The aim of this study was to compare the occlusal morphology of partial crown reconstructions made by dental technicians with reconstructions made by a fully automatic software process (biogeneric tooth model) in relation to the original natural tooth shape. MATERIAL AND METHODS: Stone replicas of natural teeth were measured three-dimensionally before preparing inlay and onlay cavities for ceramic restorations (n = 5). For each preparation, five reconstructions (in total n = 25) were made by five dental technicians. Additionally, reconstructions were calculated automatically by a software based on the biogeneric tooth model (Cerec 3D). In order to compare the two different kinds of reconstruction, an objective metrical similarity measure (shape similarity value, SSV) based on calculated volumes between compared datasets was used. RESULTS: In 22 of 25 cases, the reconstructions made by the CAD software were closer to the original situation than the reconstructions made by the technicians. Mean average SSV of reconstructions made by the technicians (310.2 ± 78.8 µm) was significantly higher (p < 0.05) than mean SSV of CAD reconstructions (biogeneric model) (222.0 ± 47.7 µm). CONCLUSIONS: In the design of naturally shaped occlusal inlay/onlay surfaces, a fully automatic CAD system can be at least as good as conventional wax-ups by dental technicians. CLINICAL RELEVANCE: The adjustment of a dental restoration to fit the morphology of surrounding tooth structures, still presents challenges for the dentist.

Tuberculous extensor tenosynovitis of the hand.

Tuberculous tenosynovitis is a rare manifestation of extrapulmonary tuberculosis (Tb), especially if solely the dorsal hand compartment is affected. In this report, we present the medical history of an immuno-competent 32-year-old man presented with a painful swelling of the right dorsal wrist. Initial inflammation onset had occurred 6 months before he consulted our service, resulting in consultation of several physicians and extensive diagnostic procedures without gaining a specific diagnosis. Finally, after extensive diagnostic tests, a tenosynovectomy was performed and tuberculosis-induced extensor tenosynovitis was detected. The diagnosis was established by positive histology, repeated specific PCR and T-SPOT.TB. Tuberculous tenosynovitis can easily be overlooked as a cause of chronic tenosynovitis particularly in immunocompetent young people lacking any risk factors.

Primary cold atmospheric plasma combined with low dose cisplatin as a possible adjuvant combination therapy for HNSCC cells-an in-vitro study.

BACKGROUND: The aim of the present study was to examine the cytostatic effects of cold atmospheric plasma (CAP) on different head and neck squamous carcinoma (HNSCC) cell lines either in isolation or in combination with low dose cisplatin. The effect of CAP treatment was investigated by using three different HNSCC cell lines (chemo-resistant Cal 27, chemo-sensitive FaDu and OSC 19). MATERIALS AND METHOD: Cell lines were exposed to CAP treatment for 30, 60, 90, 120 and 180 s (s). Cisplatin was added concurrently (cc) or 24 h after CAP application (cs). Cell viability, DNA damage and apoptosis was evaluated by dye exclusion, MTT, alkaline microgel electrophoresis assay and Annexin V-Fit-C/PI respectively. RESULTS: In all cell lines, 120 s of CAP exposure resulted in a significant reduction of cell viability. DNA damage significantly increased after 60 s. Combined treatment of cells with CAP and low dose cisplatin showed additive effects. A possible sensitivity to cisplatin could be restored in Cal 27 cells by CAP application. CONCLUSION: CAP shows strong cytostatic effects in HNSCC cell lines that can be increased by concurrent cisplatin treatment, suggesting that CAP may enhance the therapeutic efficacy of low dose cisplatin.

Influence of Clinical Parameters on the Primary Stability of a Tapered Dental Implant: A Retrospective Analysis.

PURPOSE: The aim of this study was to investigate the influence of different clinical parameters on the primary stability of a variable thread tapered implant system with a focus on surgical undersizing protocols. MATERIALS AND METHODS: This retrospective study evaluated patients who received NobelActive implants in a single institution. The relationship between the independent variables, bone quality, implant diameter, implant length, implantation time, region of the jaw, and surgical undersizing protocol, and the dependent variable, maximum insertion torque, was investigated. Statistical analysis was conducted using analysis of variance (ANOVA) and multiple linear regression. RESULTS: A total of 1,292 implants placed in 574 fully or partially edentulous patients were evaluated. For the total sample size, without further differentiation between bone qualities, statistically significantly higher primary stability values were shown for an 8% to 9% undersized group (50.33 ± 17.16 Ncm), compared with a 16% undersized group (41.88 ± 17.63 Ncm), a 20% undersized group (33.65 ± 15.78 Ncm), a 26% to 28% undersized group (34.53 ± 15.49 Ncm), and a 35% to 44% undersized group (32.78 ± 18.80 Ncm). No statistical differences were found for undersizing protocols in bone quality 4. Bone quality had the highest influence on primary stability (Welch-Test F(3, 65.57) = 119.48, P < .001, η2 = .20). Contrary to the other investigated independent variables, no statistically significant differences in primary stability were found for the different implantation times. CONCLUSION: Undersizing protocols exceeding 8% to 9% do not seem to enhance primary stability values. Further studies are needed to investigate the biologic consequences of undersizing, including the impact of implant design characteristics.

Fatty Acid Receptor CD36 Functions as a Surrogate Parameter for Lymph Node Metastasis in Oral Squamous Cell Carcinoma.

PURPOSE: To investigate the expression pattern of CD36 in a patient population with oral squamous cell carcinoma (OSCC) and to correlate CD36 expression with clinical and histopathological parameters. The hypothesis was that CD36 expression correlates with the occurrence of lymph node metastasis. METHODS: To address the study objectives, a retrospective cohort study was conducted. Study variables included demographic, histopathological and survival data. CD36 expression patterns were assessed by immunohistochemistry on tissue microarrays (TMA). Logistic regression analysis, survival analysis and Cox proportional hazards model were performed. RESULTS: High CD36 expression correlated significantly with a higher T-status, grading and occurrence of lymph node metastasis. The logistic regression with binary N status as a dependent variable showed that high CD36 expression increased the chance for lymph node metastasis 45-fold (OR = 44.7, 95% CI: 10.0-316). Patients with high CD36 expression had lower probabilities of progression-free survival. CD36 had a small and non-significant independent influence on progression-free survival. CONCLUSIONS: CD36 is expressed in OSCC and correlates with tumor grading, T-status, and especially the occurrence of lymph node metastasis. CD36 may be useful for risk stratification regarding lymph node metastasis in OSCC.

Clinical and pathologic parameters predicting recurrence of facial basal cell carcinoma: a retrospective audit in an advanced care center.

OBJECTIVES: This study was designed to investigate the associations between clinical, pathologic, and therapeutic parameters of facial basal cell carcinoma (BCC) and recurrence rates in patients treated at an advanced care center. METHODS: A retrospective cohort study was performed. Patients who presented to an advanced care center within a 6-year period with facial BCC and who received surgical treatment were included for further review according to predefined inclusion criteria. The predictor variable was defined as "negative-margin (R0) resection after the first surgery". The primary outcome variable was defined as "BCC recurrence". Descriptive and inferential statistics were computed. The significance level was set at P ≤ 0.05. RESULTS: A total of 71 patients (29 female, 42 male; average age: 71.76 years) were found to meet all of the study inclusion criteria. All BCCs had been referred, and 50.7% had been submitted to previous surgery. The mean ± standard deviation tumor diameter was 2.3 ± 1.8 cm. Recurrence of BCC was observed in 11 patients (15.5%). Large tumor diameters, increased patient age, and failure to achieve R0 resection at the first surgical appointment significantly increased recurrence rates. CONCLUSIONS: Complete facial BCC excision at the first surgical appointment is pivotal in reducing the likelihood of recurrence. The influence of the anatomic location of facial BCC on recurrence rates may be limited.

Patient-specific reconstruction plates are the missing link in computer-assisted mandibular reconstruction: A showcase for technical description.

INTRODUCTION: Preoperative planning of mandibular reconstruction has moved from mechanical simulation by dental model casts or stereolithographic models into an almost completely virtual environment. CAD/CAM applications allow a high level of accuracy by providing a custom template-assisted contouring approach for bone flaps. However, the clinical accuracy of CAD reconstruction is limited by the use of prebent reconstruction plates, an analogue step in an otherwise digital workstream. TECHNICAL REPORT: In this paper the integration of computerized, numerically-controlled (CNC) milled, patient-specific mandibular plates (PSMP) within the virtual workflow of computer-assisted mandibular free fibula flap reconstruction is illustrated in a clinical case. Intraoperatively, the bone segments as well as the plate arms showed a very good fit. Postoperative CT imaging demonstrated close approximation of the PSMP and fibular segments, and good alignment of native mandible and fibular segments and intersegmentally. Over a follow-up period of 12 months, there was an uneventful course of healing with good bony consolidation. CONCLUSION: The virtual design and automated fabrication of patient-specific mandibular reconstruction plates provide the missing link in the virtual workflow of computer-assisted mandibular free fibula flap reconstruction.

Simplified transoral load-bearing osteosynthesis with preformed mandible reconstruction plates.

Transcutaneous submandibular approaches are the preferred technique for the application of load-bearing mandibular osteosynthesis plates. However, an extraoral approach is associated with several shortcomings, like the risk of harming the facial nerve and scarring. This technical note presents a specialized mandibular reconstruction plate (MatrixMANDIBLE Preformed Reconstruction Plate [Synthes Maxillofacial, Paoli, PA]), simplifying the transoral application by its design with a preformed curvature along the lateral surface of the mandible. The application of wide-spanning plates reaching from the posterior margin of the ramus even into the contralateral body region is facilitated. Transoral application of preformed mandibular reconstruction plates seems to be a promising option to bypass external incisions and to reduce operating room time.

CAD reconstruction using contralateral mirrored anterior teeth: a 3-dimensional metric and visual evaluation.

This study evaluated the concept of computer-aided design of anterior teeth by integrating morphologic information about the mirrored contralateral teeth. With the aid of a digital 3-dimensional tooth library, ipsilateral teeth were automatically mirrored, rotated, and translated to fit in the locations of the contralateral teeth. The reconstruction outcomes were evaluated via 3-dimensional similarity measures, measurements of approximal and antagonistic relationships, and visual ratings of experts. Metric and visual judgments indicate that integrating the shape of a symmetrically located contralateral anterior tooth seems to be a suitable base concept for computer-aided design of anterior restorations.