DZZ International, 02/2020

Caries is the most common non-contagious disease worldwide. It has a higher prevalence in people of lower socioeconomic status [17, 34]. Deep carious lesions are defined as defects that extend radiologically into the inner third or quarter of dentin. This is where the pulp is at risk of exposure. When the remaining dentin thickness decreases towards the pulp, the risk of pathogenic changes in the pulp increases. In daily practice, however, it is often difficult to assess the remaining dentin thickness close to the pulp and to decide when and with which preparation a "dentin wound treatment" should be performed [21, 32]. For this reason, it is useful to consider pulp symptoms when making a diagnosis and to leave some infected dentin behind near to the pulp if there is a risk of pulp exposure. The primary aim of treating deep carious lesions is always to avoid exposing the pulp and to keep it healthy and vital. Thus, the purpose of dentin wound care is manifold; it is to protect the pulp from further exogenous noxae (such as residual monomers or thermal damage caused by light polymeri¬zation when using the adhesive technique), from toxins of microorganisms (such as lipopolysaccharides), to eradicate bacteria, as well as to stimulate the formation of reactive dentin. Furthermore, the outflow of dentinal fluid from the dentin tubules should be avoided.

Microvascular free flaps are frequently applied in midfacial reconstruction to restore mastication and functional dentition in addition to aesthetic and contour rehabilitation. Especially bilateral maxillectomy defects are multidimensional and result in quality of life deterioration and long-term impairment if not reconstructed properly. Therefore, computer-aided three- dimensional surgical planning can help to achieve not only an adequate implant-fixed dentition but also proper soft tissue conditions in the palate and alveolar ridge. In this case presentation a 70-year-old lady after multiple cancer resections in the maxilla received a fibula free flap bilateral maxillary reconstruction including palatal coverage via a perforator perfused skin flap and implant-based dental rehabilitation. Additionally, vestibuloplasty was performed to restore proper lip contours and increase lip function. A one-stage, three-dimensional planned microvascular fibula free flap reconstruction after cancer resection in combination with postoperative implant placement and vestibuloplasty is a clinically valuable treatment concept even in older patients to restore function and facial contours. Schlagwörter: fibula grafting, maxilla reconstruction, oscc, vestibulopasty

Introduction: The aim of this study was to evaluate the clinical performance of mini-implants (MI), which were used for the stabilization of double crown retained removable partial dentures (RPDs), after a middle-term period of service in a dental practice. Additionally, implant stability and patient satisfaction with the dentures were evaluated. Material and Methods: Patients who had received 10 to 13 mm long MI with diameters of 1.8, 2.1, and 2.4 mm and ball attachments for supplementary support of their existing double crown retained RPDs at least 3 years ago were included in this study. After patient chart and medical history analysis as well as the completion of an 8-item questionnaire on satisfaction with the RPD (Likert scale 1 to 5) by the participants, an experienced dentist independently examined the periodontal/peri-implant conditions; this involved measurement of implant stability by using the Periotest and the Osstell device. In addition to descriptive statistics, survival analyses based on the Kaplan-Meier and Cox regression analyses were used to estimate possible risk factors for implant loss. Results: Out of 70 reachable patients, 66 study jaws in 57 patients were examined. The duration between the time of implant placement and the follow-up examination ranged between 3 and 9 years for the examined 77 MI in 25 upper jaws and 113 MI in 41 lower jaws. The MI in 20 jaws with good bone quality (insertion torque ≥ 35 Ncm) were loaded immediately using matrices (housing with O-rings), while the other RPDs were initially soft-relined for 3–4 months. The 5-year-survival rates of the MI in the maxilla and mandible were 97.4 % (3 failures) and 86.9 % (13 failures, one fracture), while the tooth survival rates were 88 % and 88.9 %, respectively. The Cox regression analyses revealed no statistically significant effect of possible risk factors on implant failure (tooth status, smoking habits, diabetes mellitus, loading modus). In 18 of the study participants, a total of 40 MI were placed subsequent to implant or tooth loss. The aftercare of the RPDs comprised of 8 O-ring replacements and 26 denture base relinings. The complications included denture base (n = 17), secondary crown veneering (n = 11) and artificial denture teeth (n = 2) fractures. The mean Periotest values were 5.5 and 6.7 (P = 0.078), while the mean Osstell values were 38 and 33 (P 0.0001), in the maxilla and mandible, respectively. The majority of participants were very satisfied with their RPD (80 % in the maxilla, 70 % in the mandible) and nobody was dissatisfied. Discussion: The lower MI survival rate in the mandible compared with the maxilla comes as a surprise and is contrary to previous studies performed on edentulous jaws. The complications were manageable, despite implant losses and denture fractures. The stability values of MI were lower than those of standard-diameter implants. Conclusion: Strategic MI under double crown retained RPDs are a recommendable therapeutic option in the dental practice. Prospective randomized clinical studies are required to investigate this therapeutic alternative. Schlagwörter: double crown, mini-implant, removable partial denture, satisfaction, stability, strategic, survival

Recently in holistic dentistry, more statements are spread that non-vital teeth and root canal treated teeth release mercaptans and thioethers. These products are expected to cause a postulated direct toxic effect as well as pathological immune reactions. In reference to a study by Jacobi-Gresser et al., it is stated that the laboratory results can be impacted significantly by retreatment of a root canal treatment or a tooth extraction. It is therefore suggested that at allegedly increased laboratory values an extraction of a tooth with a non-vital pulp or that has already been root canal treated is indicated. Mercaptans are aromatic or ali¬phatic thioalcohols, give off a very unpleasant odor and result from degradation and the decomposition process of organic material. They naturally act as flavoring substances in milk, cheese, onion, garlic, coffee aroma and nuts. Methanthiole (methyl mercaptan) forms during bacterial protein degradation, amongst others also in human saliva. It is the main cause of halitosis, however, it also exists physiologically in the blood, brain and other human organs. Mercaptans are produced daily during the anaerobic metabolization of intestinal proteins. Increased methyl mercaptan-values in air were found in decompensated liver cirrhosis, and in patients with periodontal diseases or gastric ulcers and tumors. Thioethers are sulfur analogues of ethers, mostly insoluble in water and have an extremely unpleasant odor. The dimethyl sulfide results from the decomposition of sulfurous proteins, but is also responsible for the odor and taste of different types of truffles.