Cone Beam Computed Tomography Evaluation of the Artery in the Lateral Wall of the Maxillary Sinus: Retrospective Analysis of 602 Sinuses.

PURPOSE: This retrospective study evaluates the location of the arteries in the maxillary sinus, particularly in the middle portion, using cone beam computed tomography (CBCT) scans that can detect the lateral arteries with high reliability. METHODS: In this retrospective study, 2 experienced independent examiners evaluated 602 sinuses on CBCT scans. DISCUSSION: No significant correlation was found between the location of arteries and the patient's age, sex, or dentition. In 92.0% (P ≤ 0.001) of the sinuses, at least 1 arterial branch was detectable. CONCLUSION: Based on the CBCT scans, we found that a very high proportion of patients have the maxillary artery in their lateral sinus wall, which is important information for sinus augmentation or sinus surgery.

Influence of Mirrored Computed Tomograms on Decision-Making for Revising Surgically Treated Orbital Floor Fractures.

PURPOSE: This study evaluated whether intraoperative imaging with computer-assisted virtual reconstruction would be advantageous in reconstructions of orbital floor fractures. The surgeon's intention to revise a reconstructed primary orbital floor fracture by evaluating a postoperative mirrored computed tomographic (CT) scan was analyzed intraoperatively before wound closure, during inpatient hospitalization, and after hospitalization. The inter-rater agreement and the match of intention to revise and actual revision were analyzed. MATERIALS AND METHODS: Fifty-one anonymized postoperative CT scans of patients with a unilateral orbital floor fracture were mirrored using software. These computer-assisted virtual reconstructions were consecutively examined by 4 examiners. Seven of these patients underwent a revision. In the first part, the inter-rater agreements for all 3 times were analyzed. In the second part, the examiners' intentions to revise were compared with the actual performed revisions. RESULTS: The overall inter-rater agreements were 0.69 for the intraoperative phase, 0.55 for the in-hospital phase, and 0.39 for the post-hospital phase. The intraoperative inter-rater agreement for each examiner was 0.58 to 0.80. The Fleiss κ value for the in-hospital and post-hospital phases was lower. The comparison of the examiners' intention to revise and the actual revisions showed that 15 to 24 additional would have been revised. In contrast, 6 of 7 actual revisions would have been revised intraoperatively. The missed actual revision was the same case by all 4 examiners. The accordance of intention to revise with the actual revisions decreased during hospitalization and even more after hospitalization. This study showed strong agreement among examiners for revising anatomically incorrectly reduced orbital floor fractures intraoperatively by evaluating postoperative mirrored CT scans. During the in-hospital and post-hospital phases, the restraints against revision seemed to increase, thus leading to poorer inter-rater agreement. This analysis of postoperative CT scans with computer-assisted virtual reconstructions of the orbit would have led to considerably more revisions intraoperatively, but all actual revisions were detected except for 1 case. This case was the same for all 4 examiners. Operation time would have been prolonged in the additional revised cases, but a better anatomic reconstruction would have been achieved. Furthermore, the intraoperative result of the reconstruction would have been controlled instantly and corrected immediately, if needed. CONCLUSION: This study showed that of 6 of 7 actual revisions, implant placement would have been revised intraoperatively by all 4 examiners, if intraoperative imaging with computer-assisted virtual reconstruction of the orbit would have been applied. Therefore, the authors suggest that intraoperative imaging with computer-assisted virtual reconstruction could be advantageous in the prevention of later revisions of orbital floor fractures. In this study, the threshold to revise implant placement intraoperatively seemed to be lower when using intraoperative imaging with virtual reconstructions, because considerably more cases would have been revised intraoperatively by the examiners. In the in-hospital and post-hospital phases, this threshold increased, suggesting the more important role of clinical findings. It is uncertain whether the actual surgeons would have revised the same cases as the examiners if they had used intraoperative imaging with virtual reconstructions for their deliberation. However, the intraoperative inter-rater agreement was good and cost-intensive postoperative revisions might be prevented.

Is lymph-node ratio a superior predictor than lymph node status for recurrence-free and overall survival in patients with head and neck squamous cell carcinoma?

INTRODUCTION: TNM status is questioned as an exact predictor of survival in different tumour entities. Recently, lymph node ratio (LNR) has been described as a predictor of survival in patients with HNSCC. The purpose of this study was to evaluate to which degree LNR could be used as a more accurate predictor than TNM staging? METHODS: A total of 291 patients, with a follow-up of at least 3 years, were analyzed using log-rank statistic, univariate and multivariate data analyzes, and p values, for prediction of lymph node ratio on overall and recurrence-free survival. RESULTS: Survival differed significantly if patients were stratified for LNR. Impact of LNR on survival was significantly different even in patients with extracapsular spread. Patients with pN0 had no survival benefit compared with patients with pN1 or higher with a LNR lower than 6 %. CONCLUSIONS: LNR is a prognostic tool in patients with a lymph node status pN0-pN2b. LNR remained significant even in patients with extracapsular spread, contrary to TNM status. With LNR, stratification for high-risk patients (higher than 6 % LNR) can be evaluated easily. We would suggest using LNR in the clinical routine.

[Fibromatous Epulis: A Clinical Case Report].

A 35-year-old patient presented with a painless, broad-based exophytic lesion in the buccal interdental region between teeth 13 and 14. Despite oral hygiene efforts the lesion persisted for around one year. Radiology excluded bone involvement, and histopathology after excision confirmed a fibromatous epulis, which is characterized by collagen-rich connective tissue. There was no recurrence within one-year follow-up. Surgical removal proved to be efficient.

Neurologischer Notfall nach dentaler Implantation - was nun?

Mit der Verbreitung von Zahnimplantaten ist die Zahl neurologischer Komplikationen gestiegen, wobei diese vor allem im Unterkiefer vorkommen. Verletzungen des Nervus alveo- laris inferior sind eine ernste Komplikation mit Inzidenzen für transiente Nervschäden bis zu 24% und persistierenden Schädigungen bis zu 11%.

OrthoCalc: The six degrees of freedom measurement workflow of rotational and displacement changes for maxilla positioning evaluation.

BACKGROUND: This study is undertaken to establish the accuracy and reliability of OrthoCalc, a 3D application designed for the evaluation of maxillary positioning. METHODS: We registered target virtual planned models, maxillary models from pre-operative and post-operative CT scans, and post-operative intra-oral scans to a common reference system, allowing for digital evaluation. To assess rotational changes, we introduced a novel measurement method based on virtual cuboid models. Displacement errors were calculated based on proposed registration matrices. We also compared OrthoCalc to established commercial medical software as a benchmark. RESULTS: Statistical significance calculated showed no significant differences between OrthoCalc and commercial software. the biggest error of 0.04 degree in rotation change was found in the yaw. A maximum displacement change of 0.75 mm was found in the X direction. CONCLUSIONS: Our study validates OrthoCalc as a precise and reliable tool for assessing maxillary position changes with six degrees of freedom in orthognathic surgery, endorsing its clinical utility.

Cranial vault growth in multiple-suture nonsyndromic and syndromic craniosynostosis: a postoperative long-term anthropometric follow-up.

Long-term anthropometric follow-up of cranial vault growth may considerably add valuable information to current literature focusing on treatment strategies for premature multiple-suture craniosynostosis. The aim of this paper was to compare postoperative growth patterns of nonsyndromic and syndromic multiple-suture craniosynostotic children with sex-matched and age-matched children from the typically developing population. Forty-one multiple-suture craniosynostotic patients (19 nonsyndromic and 22 syndromic) were included in this 5-year follow-up. Anthropological data of sex-matched and age-matched normal Swiss children served as a control. A standardized time protocol for anthropometric skull measurements (head circumference and cephalic index) was used. Data were converted into Z-scores for standardized intercenter comparison. All patients showed a marked benefit in cranial vault shape after open skull remodeling. Significant differences in long-term cranial vault growth pattern could be seen between the nonsyndromic and the syndromic groups compared to the control group.

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

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

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

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

Biomechanical feasibility of non-locking system in patient-specific mandibular reconstruction using fibular free flaps.

Mandibular reconstruction with free fibular flaps is frequently used to restore segmental defects. The osteosythesis, including locking and non-locking plate/screw systems, is essential to the mandibular reconstruction. Compared with the non-locking system that requires good adaption between plate and bone, the locking system appears to present a better performance by locking the plate to fixation screws. However, it also brings about limitations on screw options, a higher risk of screw failure, and difficulties in screw placement. Furthermore, its superiority is undermined by the advancing of patient-specific implant design and additive manufacturing. A customized plate can be designed and fabricated to accurately match the mandibular contour for patient-specific mandibular reconstruction. Consequently, the non-locking system seems more practicable with such personalized plates, and its biomechanical feasibility ought to be estimated. Finite element analyses of mandibular reconstruction assemblies were conducted for four most common segmental mandibular reconstructions regarding locking and non-locking systems under incisal biting and right molars clenching, during which the influencing factor of muscles' capacity was introduced to simulate the practical loadings after mandibular resection and reconstruction surgeries. Much higher, somewhat lower, and similar maximum von Mises stresses are separately manifested by the patient-specific mandibular reconstruction plate (PSMRP), fixation screws, and reconstructed mandible with the non-locking system than those with the locking system. Equivalent maximum displacements are identified between PSMRPs, fixation screws, and reconstructed mandibles with the non-locking and locking system in all four reconstruction types during two masticatory tasks. Parallel maximum and minimum principal strain distributions are shared by the reconstructed mandibles with the non-locking and locking system in four mandibular reconstructions during both occlusions. Conclusively, it is feasible to use the non-locking system in case of patient-specific mandibular reconstruction with fibular free flaps based on the adequate safety, comparable stability, and analogous mechanobiology it presents compared with the locking system in a more manufacturable and economical way.

[Oral metastasis of a renal cell carcinoma. A case report concerning the first manifestation of a renal cell carcinoma as bone metastasis in the mandible]. / Orale Metastase eines Nierenzellkarzinoms. Ein Fallbericht über die Erstmanifestation eines Nierenzellkarzinoms als ossäre Metastase im Unterkiefer.

UNLABELLED: Tumorous lesions of the oral cavity are mostly of dental or local pathological origin. On occasion, they may have a distant origin outside the field of dentistry. Under certain circumstances, this can lead to serious consequences. Renal cell carcinomas are known for their frequent metastasis to the lungs, liver, bones, and brain. Metastases to the oral cavity are rare. CASE REPORT: A 68-year-old woman with previously unknown renal cell carcinoma is presented. By biopsy of a suspicious lesion, an intraoral clear cell carcinoma was diagnosed. In the following tumor staging, a metastasizing clear cell renal cell carcinoma was identified as the focus and a systemic therapy was initiated. SUMMARY: This case report exemplarily shows the importance of timely histological verification of each new intraoral lesion. Under certain circumstances, a diagnosis of a surprising and potentially life-threatening condition may be made in time to initiate adequate treatment.

3-Dimensional imaging for lower third molars: is there an implication for surgical removal?

PURPOSE: Surgical removal of impacted third molars may be the most frequent procedure in oral surgery. Damage to the inferior alveolar nerve (IAN) is a typical complication of the procedure, with incidence rates reported at 1% to 22%. The aim of this study was to identify factors that lead to a higher risk of IAN impairment after surgery. MATERIALS AND METHODS: In total 515 surgical third molar removals with 3-dimensional (3D) imaging before surgical removal were retrospectively evaluated for IAN impairment, in addition to 3D imaging signs that were supposed predictors for postoperative IAN disturbance. Influence of each predictor was evaluated in univariate and multivariate analyses and reported as odds ratio (OR) and 95% confidence interval (CI). RESULTS: The overall IAN impairment rate in this study was 9.4%. Univariate analysis showed narrowing of the IAN canal (OR, 4.95; P < .0001), direct contact between the IAN and the root (OR, 5.05; P = .0008), fully formed roots (OR, 4.36; P = .045), an IAN lingual course with (OR, 6.64; P = .0013) and without (OR, 2.72; P = .007) perforation of the cortical plate, and an intraroot (OR, 9.96; P = .003) position of the IAN as predictors of postoperative IAN impairment. Multivariate analysis showed narrowing of the IAN canal (adjusted OR, 3.69; 95% CI, 1.88 to 7.22; P = .0001) and direct contact (adjusted OR, 3.10; 95% CI, 1.15 to 8.33; P = .025) to be the strongest independent predictors. CONCLUSION: Three-dimensional imaging is useful for predicting the risk of postoperative IAN impairment before surgical removal of impacted lower third molars. The low IAN impairment rate seen in this study-compared with similar selected study groups in the literature of the era before 3D imaging-indicates that the availability of 3D information is actually decreasing the risk for IAN impairment after lower third molar removal.

Histological evaluation of microsurgical revascularized bone in the intraoral cavity: does it remain alive?

INTRODUCTION: Microsurgical revascularized fibula graft is a standard for the reconstruction of mandible or maxilla after major resection. Usually, screwed implants are inserted as a second procedure for dental rehabilitation. A lot has been published about the advantages of vascularized bone grafts, but until now there is only little information about long-term viability of inserted bone grafts. MATERIAL AND METHODS: In this study, previously inserted vascularized fibula bone grafts were examined histologically. Bone biopsies were taken during dental implant insertion procedure in average of 19 months after insertion of bone grafts from 10 patients. RESULTS: All bone biopsies showed partially or totally necrotic bone, although clinical examination and postoperative monitoring of the revascularized bone remained unremarkable. CONCLUSION: The results of histological examination are surprising, due to the fact of previous insertion of a vascularized bone graft and pretended osseointegration of inserted dental implants with satisfying primary stability. Therefore, one would expect vital bone. For better understanding how much viability is really necessary for sufficient remodeling of inserted bone grafts for adequate functional load, further studies should be performed.

A quick guide to positioning the transbuccal set.

Exact positioning of the transbuccal set can be tricky, especially under aggravating circumstances as present scarring or high body mass index. It may result in multiple skin incisions. This article presents a simple and fast guidance technique that can help in the exact positioning of skin incision and transbuccal set.

Precise screw positioning at the mandibular angle: computer assisted versus template coded.

BACKGROUND: Buried intraoral devices for distraction osteogenesis in mandibular deformities have numerous advantages, but success depends on the precise positioning of these devices. Although most centers nowadays use template-guided techniques for precise positioning, computer navigation has been described as a promising technique. Surgical navigation during device placement could become a viable method because it affords certainty in defining a device position. METHODS: A clinical situation was simulated by means of mounting a mandible model inside a phantom head. Screws were positioned according to a preoperative plan through transoral and transbuccal approaches, with both template-coded and freehand computer navigation. RESULTS: With template-coded navigation, the medium deviation from the planned position was 0.63 mm (range, 0.00-1.24 mm). With commercial freehand surgical computer navigation, the medium deviation was significantly higher at 0.98 mm (range, 0.00-3.13 mm). CONCLUSIONS: Computer-assisted surgery can provide a high level of accuracy in the region of the mandibular angle where precision is crucial for buried intraoral distraction devices. However, template-coded guidance does provide a significantly higher level of accuracy and therefore represents the gold standard.

[Chronic orofacial pain (OFP) of different origin. A case report]. / Chronischer Gesichtsschmerz unterschiedlicher Genese. Ein Fallbericht.

INTRODUCTION: Therapy of chronic orofacial pain (OFP) is often a challenge since OFP can be triggered by numerous medical conditions. Pulpitis is frequently related to acute OFP, only in rare cases pulpitis elicits chronic OFP e. g. due to a cracked tooth. Hypertrophy of masticatory muscles can also cause pain. While this pathosis is easily diagnosed, hypertrophy of masticatory muscles is challenging to treat. METHODS: The presented case demonstrates a combination of a cracked tooth and a symtomatic hypertrophy of the masseteric muscle in a 19-year old patient. The patient suffered from diffuse chronic OFP for more than four month. After diagnosis an interdisciplinary step-by-step treatment plan was realized with re-evaluation and adjustment. RESULTS: After physiotherapy and medicamentous pain control intramuscular injection of Botolinum toxin type-A was performed with remission of the muscle hypertrophy but only partial success regarding pain control. After root canal treatment of a cracked tooth the patient was free of symptoms. CONCLUSION: The high degree of specialization in dental medicine requires a multidisciplinary approach for OFP not thoroughly responding to therapy. Stepwise diagnostics and treatments are recommended to clarify the pathology and to address multiple causes of disease.

[New rules for diagnostic monitors in oral and maxillofacial radiology in Switzerland - a statement of the Swiss Association of Dentomaxillofacial Radiology]. / Neue Regeln für Monitore zur Befundung dentaler und maxillofazialer Röntgenbilder ­ Eine Stellungnahme der Schweizerischen Gesellschaft für Dentomaxillofaziale Radiologie (SGDMFR).

A considerable number of new regulations for oral and maxillofacial radiology was introduced in Switzerland roughly three years ago. The rules had to be followed immediately (date of entry was 1 January 2018) without any transition period. Since then, additional guidance papers have been published by the Swiss government. A current guidance paper is focusing on diagnostic monitors. Different demands for these must be met, which are related to the respective medical field, the type of imaging technology, and also environmental factors. Together with the many other regulations already enacted mainly in 2018 this is another piece of the puzzle on the road to perfecting regulations in oral and maxillofacial radiology with the aim to improve patient care.

[Conduction anesthesia of the infraorbital nerve - A guide to intraoral nerve block anesthesia of the infraorbital nerv]. / Leitungsanästhesie des Nervus infraorbitalis.

In order to be able to perform major oral surgery in the upper jaw, sufficient local analgesia is indispensable. While the inferior alveolar nerve is often blocked for dental treatments in the lower jaw, block anesthesia in the upper jaw is less common. This article gives pragmatic advice on how to block the infraorbital nerve. By using this method patients comfort is significantly improved and the surgeon can focus on the treatment at hand.

Preclinical study of additive manufactured plates with shortened lengths for complete mandible reconstruction: Design, biomechanics simulation, and fixation stability assessment.

BACKGROUND: A combination of short titanium plates fabricated using additive manufacturing (AM) provides multiple advantages for complete mandible reconstruction, such as the minimisation of inherent implant deformation formed during AM and the resulting clinical impact, as well as greater flexibility for surgical operation. However, the biomechanical feasibility of this strategy is still unclear, and therefore needs to be explored. METHOD: Three different combinations of short mandible reconstruction plates (MRPs) were customised considering implant deformation during the AM process. The resulting biomechanical performance was analysed by finite element analysis (FEA) and compared to a conventional single long MRP. RESULTS: The combination of a long plate and a short plate (Design 3 [LL61 mm/RL166 mm]) shows superior biomechanical properties to the conventional single long plate (Design 1 [TL246 mm]) and reveals the most reliable fixation stability among the three designs with short plates. Compared to conventional Design 1, Design 3 provides higher plate safety (maximum tensile stress on plates reduced by 6.3%), lower system fixation instability (relative total displacement reduced by 41.4%), and good bone segment stability (bone segment dislocation below 42.1 µm) under masticatory activities. CONCLUSIONS: Preclinical evidence supports the biomechanical feasibility of using short MRPs for complete mandible reconstruction. Furthermore, the results could also provide valuable information when treating other large-sized bone defects using short customised implants, expanding the potential of AM for use in implant applications.

Biomechanical comparison of locking and non-locking patient-specific mandibular reconstruction plate using finite element analysis.

Patient-specific mandibular reconstruction plate (PSMRP), as one of the patient-specific implants (PSIs), offers a host of benefits to mandibular reconstruction. Due to the limitation of fabricating screw hole threads in the PSMRP, 3D printed PSMRP is applied to the non-locking system directly in the mandibular reconstruction with bone graft regardless of the locking system. Since the conventional manual-bending reconstruction plate (CMBRP) provides better fixation in the locking system, it needs to be validated whether the locking PSMRP performs better than the non-locking PSMRP in the patient-specific mandibular reconstruction. Thereupon, the purpose of this study was to compare the biomechanical behavior between the locking and non-locking PSMRP. Finite element analysis (FEA) was used to conduct the biomechanical comparison between the locking PSMRP and non-locking PSMRP by simulating the momentary incisal clenching through static structural analysis. Mandible was reconstructed through the virtual surgical planning, and subsequently a 3D model of mandibular reconstruction assembly, including reconstructed mandible, PSMRP, and fixation screws, was generated and meshed for the following FEA simulations. In the form of equivalent von Mises stress, equivalent elastic strain, and total deformation, the locking PSMRP demonstrated its higher strengths of preferable safety, desirable flexibility, and anticipated stability compared with the non-locking PSMRP, indicated by much lower maximum stress, lower maximum strain and equivalent displacement. Locking PSMRP/screw system provides a better fixation effect to the patient-specific mandibular reconstruction than the non-locking one as a result of its productive fixation nature. FEA plays a paramount role in pre-validating the design of PSMRP through the biomechanical behavior evaluation in static structural analysis.