[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%.

[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.

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.

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.

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.

[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.

Accuracy of computer-assisted mandibular reconstructions with free fibula flap: Results of a single-center series.

OBJECTIVES: We evaluated the accuracy of computer-assisted mandibular reconstructions. PATIENTS AND METHODS: We retrospectively reviewed data for 26 patients who had mandibular reconstruction with a microvascular free fibula flap, January 2015 to June 2018. Postoperative mandible models were obtained from computed tomography scans. After registering the models to the corresponding preoperative plan, we performed comparative measurements. Patients were grouped by condylar involvement and subdivided based on number of fibular segments used for reconstruction. For each segment, we measured length and osteotomy angles. For the final postoperative outcome, we compared intercoronoid, intergonial, and anteroposterior distances and intersegmental plane shift. RESULTS: Means (SD) for deviation of each osteotomy angle and fibular segment length were 1.98° (2.98) and 1.78 mm (2.69), respectively, remaining constant across subgroups. Other mean values were as follows: intercoronoid distance deviation, 3.86 mm (range, 0.20-11.21 mm); intergonial distance deviation, 3.14 mm (range, 0.05-8.28 mm); anteroposterior distance deviation, 2.92 mm (range, 0.03-8.49 mm); and intersegmental plane shift, 11.00° (range, 2.76-24.15°). Where the condyle was preserved, the intercoronoid and intergonial deviation means differed significantly (respectively 5.02 mm and 4.88 mm, both P < 0.05) for one-segmented and three-segmented fibular reconstructions. Furthermore, reconstructions involving the condylar region compared with condyle preservation showed significantly different intersegmental plane shifts (7.18°; P < 0.05). CONCLUSION: Computer-assisted surgery provides cutting guides for obtaining accurate fibular segments, but current fixation methods lead to inaccuracies and reproducibility errors. In multisegmental transfer with condylar involvement, computer-assisted fixation is recommended to ensure accuracy of the preoperative plan.

Drug prescription by the dentist ­ choices during pregnancy and lactation period / Die zahnärztliche Verordnung von Arzneimitteln während der Schwangerschaft und in der Stillzeit

Pregnant women undergo several physiological changes ­ including when it comes to taking medication. Many substances, when taken by the expectant or lactating mother, will be transferred to the foetus or newborn, and not all drugs that help the mother will be beneficial for the baby. Especially in early pregnancy, during organogenesis, the foetus is highly sensitive. If this early development is disturbed by harmful substances such as certain medications, there can be serious consequences. In the worst case, the child is born with a malformation or is limited in its mental development. But later in the course of pregnancy, too, the use of certain drugs is dangerous. Although the risk of malformations now is no longer as high as in the first few weeks, certain drugs can, for example, trigger contractions or affect the baby.

Visiting the dentist during pregnancy / Der Zahnarztbesuch während der Schwangerschaft

In pregnancy, it is necessary to pay particu­lar attention to oral health, as inflammatory periodontal changes can occur due to the ex­ceptional hormonal situation. The popular be­lief, still existing today, that «each pregnancy costs the woman a tooth¼ is no longer valid considering conventional oral hygiene mea­sures and the fact that most pregnant women are very conscious of their nutrition (diet).

Therapeutic options to manage bleeding in a dentist's office / Therapieoptionen bei Blutungen in der zahnärztlichen Praxis

This manuscript provides an overview of therapeutic options for the problem of bleeding in a dentist's office. Bleeding after tooth extraction is a very common finding in dental medicine and persistent blood in the mouth is obviously uncomfortable and sometimes terrifying for the patient. Most bleedings can be stopped simply with compression, in some cases a homeostatic therapy is necessary. For local compression, a swab with tranexamic acid is useful. If local compression is not sufficient, sutures are often an option. A very effective therapy would also be Tabotamp®, a local hemostypticum which is placed onto the bleeding and should increase the thrombocytic aggregation. In the worst case Floseal®, a human Thrombin, can be placed locally. It stops the bleeding very fast and sufficiently.

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.

Patients with platelet aggregation inhibitors in the dental office / Patienten mit Thrombozytenaggregationshemmern in der Zahnarztpraxis

Antiplatelet agents with the active ingredients acetylsalicylic acid (Aspirin® protect 100), clopidogrel (Iscover®, Plavix®), prasugrel (Efient®) or ticagrelor (Brilique™) prevent the clumping of platelets and thus the formation of small clots at constrictions of the coronary arteries or on the metal struts of stents in the coronary artery or in bypass grafts. Large-scale studies have shown that taken regularly, these drugs can extend life and help prevent heart attacks. Especially in patients with newly implanted stents, the combination of the above-mentioned agents prevents sudden complete occlusion of the vessel concerned. By paying careful attention to contraindications and pursuing the early detection of possible side effects, drug-induced complications can be prevented.

Retrospective analysis of 471 surgically treated zygomaticomaxillary complex fractures.

PURPOSE: Zygomaticomaxillary complex (ZMC) fractures are frequent in facial trauma; only fractures of the mandible are more common. Although the frequency of these fractures is geographically consistent, the aetiology differs widely among countries and even regions. Differences in socio-economic status and the ageing population seem to be two causes. This retrospective epidemiological study evaluates patients who were surgically treated for ZMC fractures at a Swiss university clinic. MATERIALS AND METHODS: This study included 471 patients who were surgically treated for ZMC fractures in an oral and maxillofacial surgery clinic at a Swiss university hospital between January 2004 and December 2012. Complicated fractures such as LeFort II/III and bilateral ZMC fractures were excluded. Data on gender, age, and type of trauma were recorded. Fractures were classified by aetiology: motorised road traffic (car or motorcycle), bicycle, interpersonal violence, sports, falls (both less than and greater than 3 m in height) and other causes. RESULTS: A total of 350 patients were male (74%), and 121 were female (26%). The ZMC fractures were most likely to occur in the third decade (117 cases, 25%). A predominance of male patients was found in the young age groups, but an equal ratio was found in the elderly groups. Etiologically, falls of less than 3 m were the most common cause of ZMC fractures (125 cases, 27%). Interpersonal violence was second (88 patients, 19%); male patients dominated this group, which had a male-to-female ratio of 21:1. A predominance of male patients was found in every subdivision when analysing by aetiology and gender. The lowest proportion of males (57%) was found for falls of less than 3 m. CONCLUSION: In our study, interpersonal violence and falls outnumbered road traffic accidents among causes of maxillofacial fractures. This is probably a consequence of strict road and work laws. Additionally, the older and more active populations accounted for the highest proportion of falls, and young male patients were the predominant victims of ZMC fractures.

Amoxicillin mit Clavulansäure. Standardantibiotikum im allgemeinzahnärztlichen Alltag.

This script gives a pragmatic advice for general dentists on accurate use of amoxicillin with clavulanic acid considering current literature at acute inflammatory disease. In absence of contraindications a twice daily formulation of 1g amoxicillin with clavulanic acid is the first choice for concomitant therapy after treating the cause of inflammation or prophylaxis. Compared to clindamycin the concentration of amoxicillin in teeth and bone (Hallig 2014) is higher and has less gastrointestinal side-effects (Bax 2007). Furthermore it is prescribable during pregnancy and lactation. With these advantages amoxicillin with clavulanic acid is the first choice of antibiotics in general dental medicine.

Traitement médicamenteux du lichen plan buccal.

Oral lichen planus is a relatively common T-cell mediated inflammatory disease with potential malignant transformation. It may present itself with pain and oral lesions such as ulcers and Wickham’s striae. Treatment includes topical corticosteroids, preferably Clobetasol, immunosuppressive drugs and retinoids. Hyaluronic acid and aloe vera have been proven to be successful. If topical treatment fails, systemic therapy with corticosteroids may be needed. Because of the potential malignant transformation periodic follow-up is mandatory.

Drug-induced anaphylaxis. Adrenalin as emergency drug in anaphylaxis. / Arzneimittelinduzierte Anaphylaxie.

Anaphylaxis is defined as a serious allergic or hypersensitivity reaction in the most cases as a result of an IgE-mediated allergic reaction that is rapid in onset and may cause death. Common triggers are foods, insect stings, and medications. The medical treatment includes, epinephrine, glucocorticoids, antihistamines and inhaled bronchodilators, with the aim to prevent progression to life-threatening respiratory and/or cardiovascular symptoms.