Oxygen-Releasing Hyaluronic Acid-Based Dispersion with Controlled Oxygen Delivery for Enhanced Periodontal Tissue Engineering.

Periodontitis is a chronic biofilm-associated inflammatory disease of the tooth-supporting tissues that causes tooth loss. It is strongly associated with anaerobic bacterial colonization and represents a substantial global health burden. Due to a local hypoxic environment, tissue regeneration is impaired. Oxygen therapy has shown promising results as a potential treatment of periodontitis, but so far, local oxygen delivery remains a key technical challenge. An oxygen (O2)-releasing hyaluronic acid (HA)-based dispersion with a controlled oxygen delivery was developed. Cell viability of primary human fibroblasts, osteoblasts, and HUVECs was demonstrated, and biocompatibility was tested using a chorioallantoic membrane assay (CAM assay). Suppression of anaerobic growth of Porphyromonas gingivalis was shown using the broth microdilution assay. In vitro assays showed that the O2-releasing HA was not cytotoxic towards human primary fibroblasts, osteoblasts, and HUVECs. In vivo, angiogenesis was enhanced in a CAM assay, although not to a statistically significant degree. Growth of P. gingivalis was inhibited by CaO2 concentrations higher than 256 mg/L. Taken together, the results of this study demonstrate the biocompatibility and selective antimicrobial activity against P. gingivalis for the developed O2-releasing HA-based dispersion and the potential of O2-releasing biomaterials for periodontal tissue regeneration.

The reproducibility of electronic color measurements of the marginal gingiva.

INTRODUCTION: This study evaluated the reproducibility of electronic color determination system evaluations of the marginal gingiva, which could be important for adhesive cervical fillings or prosthetic restorations that imitate the gingiva. MATERIAL AND METHODS: In 50 subjects, the L*, a*, and b* color coordinates were evaluated five times at a point in the marginal area of a central incisor using different electronic color determination systems: (SP) Shadepilot, (ES) Easyshade, (CE) Crystaleye, and (SV) X-Rite. The mean color difference (ΔE) and its standard deviation between the five measurements from each participant were calculated separately for each device. Further ICC for interdevice reliability was determined. RESULTS: The L*, a*, and b* color coordinates and ΔE values differed significantly among the systems (p < 0.001). Within each patient and measurement system, ΔE ranged from 1.4 to 3.2 (SD 1.1-2.5), L* from 2.6 to 5.7 (SD 2.6-5.7), a* from 11.9 to 21.3 (SD 3.6-3.9), and b* from 15.1 to 28.9 (SD 1.7-4.3). Interdevice reliability ranged between 0.675 and 0.807. CONCLUSIONS: Color determination of the marginal gingiva using the electronic tooth color determination systems tested herein showed limited reproducibility. The results obtained with the different measurement systems differed enormously. CLINICAL RELEVANCE: These results show that the electronic color measurement devices tested allow no high reproducible determination of color coordinates of the marginal gingiva.

Addressing Model Uncertainties in Finite Element Simulation of Electrically Stimulated Implants for Critical-Size Mandibular Defects.

OBJECTIVE: Electrical stimulation is known to enhance bone healing. Novel electrostimulating devices are currently being developed for the treatment of critical-size bone defects in the mandible. Previous numerical models of these devices did not account for possible uncertainties in the input data. We present the numerical model of an electrically stimulated minipig mandible, including optimization and uncertainty quantification (UQ) methods that allow us to determine the most influential parameters. METHODS: Uncertainties in the optimized finite element model are quantified using the polynomial chaos method that is implemented in the open-source Python toolbox Uncertainpy. The volumes of understimulated, beneficially stimulated, and overstimulated tissue are considered quantities of interest because they may significantly impact the expected healing success. Further, the current is a substantial quantity, limiting the lifetime of a battery-driven stimulation unit. With sensitivity analyses, the most critical parameters in the numerical model can be identified. Thus, we can learn which parameters are particularly relevant, for example, when conceptualizing the stimulation unit or planning the manufacturing process. RESULTS: The results of this study show that the parameters of the electrode-tissue interface (ETI), as well as the conductivity within the defect volume, have the most significant impact on the model results. CONCLUSIONS: The UQ results suggest that careful characterization of the ETI and the dielectric tissue properties is crucial to reduce these uncertainties. SIGNIFICANCE: The numerical model regarding uncertainties yields important implications for reliable implant design and clinical translation.

Diagnostic tests for titanium hypersensitivity in implant dentistry: a systematic review of the literature.

PURPOSE: There are rising concerns about titanium hypersensitivity reaction regarding dental endosseous implants. This review aims to summarize and compare the validity and reliability of the available dermatological and laboratory diagnostic tests regarding titanium hypersensitivity. The following PICO design was used: In Patients with titanium dental implants (P) does epicutaneous testing (ECT) (I), compared to lymphocyte transformation test (LTT) or Memory Lymphocyte Immunostimulation Assay (MELISA) (C) detect hypersensitivity reactions (O)? A literature search was performed including all studies dealing with this topic. Studies regarding orthopedic implants were excluded. METHODS: Three databases (MEDLINE PubMed, Cochrane Library, SciELO) were screened for suitable studies and an additional manual search was also performed. Literature regarding hypersensitivity reactions in orthopedic implants, hypersensitivity reactions regarding implants not related to dental or maxillofacial surgery, animal studies and in vitro studies were excluded. A quality assessment of all selected full-text articles was performed. Randomized, controlled trials were evaluated with the Cochrane Risk of Bias Tool I. Cohort studies were assessed according to the New Castle-Ottawa Scale and case series according to Moga et al. (Development of a quality appraisal tool for case series studies using a modified Delphi technique. 2012). RESULTS: 10 studies were included in the quantitative synthesis and available for the endpoint diagnostics of intolerance reactions to titanium dental implants: 2 clinical studies, 7 cohort studies and 1 case series. The potential for bias (internal validity) for these studies was overall rated as high. CONCLUSIONS: The study of the available literature regarding ECT and MELISA or LTT in patients with suspected titanium hypersensitivity showed inconsistent results in terms of reliability and validity and thus, those tests should be regarded cautiously. There is strong evidence that titanium hypersensitivity in dental implants is associated with innate immunity: unspecific pro-inflammatory responses due to particle induced hyperreactivity of macrophages or toxicological responses especially towards nanoparticles rather than activation of the adaptive immune system. Therefore, tests detecting allergies do not seem expedient and inflammatory clinical signs should be regarded as leading parameters.

The German S3 guideline on titanium hypersensitivity in implant dentistry: consensus statements and recommendations.

BACKGROUND: There is currently a lack of guidelines for clinicians regarding titanium hypersensitivity in implant dentistry. Diagnostic tests such as the epicutaneous test or the lymphocyte transformation test showed inconsistent results regarding reliability and validity and thus, evidence-based consensus recommendations regarding diagnostic and therapeutic options may be helpful in clinical decision-making. Therefore, the German S3 guideline on titanium hypersensitivity in implant dentistry was developed. FINDINGS: In the objectives, procedure, voting method and venue were defined and the consensus participants were invited. A systematic literature research was performed, and the overall quality of the evidence was rated according to the GRADE working group. Eight recommendations were formulated within the framework of a structured consensus conference under independent moderation and could be voted on with strong consensus (> 95% agreement). The formulated statements and recommendations were developed in small groups according to the guidelines of the Association of the Scientific Medical Societies in Germany (AWMF) and were discussed and agreed upon in the plenum. CONCLUSIONS: For reasonable decision-making, a patient's clinical symptoms should be regarded as leading parameters, which are usually expressed by a local inflammatory reaction with subsequent disturbed osseous integration. Allergy tests, such as the epicutaneous test or the lymphocyte transformation test are not helpful in titanium intolerance assessments, since these tests indicate T cell-mediated allergies, which are not observed in titanium intolerance reactions. Other metals and impurities that might be present in superstructures or alloys also need to be considered as the cause of an intolerance reaction and a trigger for contact sensitization. In the case of a suspected titanium particle-related, local immunologically induced inflammatory reaction with subsequent impaired osseous integration, dental ceramic implants can be considered as a therapeutic option.

Unique manifestation of a multifocal adult rhabdomyoma involving the soft palate-case report and review of literature.

Extracardiac adult rhabdomyoma is a rare benign tumor, which mainly occurs in the head and neck region and originates from striated muscle tissue. We report a 64-year-old male with simultaneous diagnosis of three adult rhabdomyomas including the soft palate and performed a review the literature on multifocal adult rhabdomyoma (mARM). Including the present case, 27 mARM with a range of 2-7 lesions per patient were collected. Mean age at diagnosis was 65 years with a male (23) to female (4) ratio of 5.75:1. Common localizations were parapharyngeal space (35%), larynx (14%), submandibular (13%), paratracheal region (14%), tongue (10%), floor of mouth (9%), neck (3%) and soft palate (2%). In accordance to this review, this the first case of mARM with involvement of the soft palate.

Vertical osteoconductive characteristics of titanium implants with calcium-phosphate-coated surfaces - a pilot study in rabbits.

INTRODUCTION: Osteoconductive characteristics of different implant surface coatings are in the focus of current interest. The aim of the present study was to compare the vertical osteoconductivity at the implant shoulder of supracrestal inserted calcium-phosphate coated implants (SLA-CaP) with conventional sand-blasted/acid-etched (SLA) implants in a rabbit model. MATERIALS AND METHODS: SLA-CaP and SLA implants were inserted bilaterally in the mandible of four rabbits in a split-mouth design. The implants were placed 2 mm supracrestal. After 3 weeks, at the left and right implant shoulder, the percentage of linear bone fill (PLF) as well as bone-implant contact (BIC-D) were determined. RESULTS: After 3 weeks, newly formed woven bone could be found at the shoulder of the most of both surface-treated implants (75%). PLF was significantly higher in SLA-CaP implants (11.2% vs. 46.5%; n = 8, p = .008). BIC-D was significantly increased in the SLA-CaP implants (13.0% vs. 71.4%; n = 8, p < .001) as well. CONCLUSION: The results of this study show for the first time that calcium-phosphate coated surfaces on supracrestal inserted implants have vertical osteoconductive characteristics and increase the bone-implant contact at the implant shoulder significantly in a rabbit model. In clinical long-term settings, these implants may contribute to a better vertical bone height.

A new method for volumetric evaluation of gingival recessions: a feasibility study.

BACKGROUND: This preliminary in vitro study, presented at the General Session of the International and American Association for Dental Research in 2010 (Barcelona, Spain), evaluates whether three-dimensional (3D) optical scanning and subsequent superimposing procedures could be used for reproducible volumetric evaluation of gingival recession. METHODS: Silicone impressions were taken of mandibular and maxillary master casts, and eight stone replicas of each master cast were produced. Each replica was scanned 10 times with a 3D optical system, and 3D datasets representing the computer-aided design reference models were calculated using a triangulation method. Marks designating gingival recession were scratched into the anterior segments of the replicas. The modified replicas were then scanned 10 times, and 3D datasets were calculated and subsequently superimposed. Differences in the volume of the gingival recession were recorded with reference to the initial data. RESULTS: The determination of gingival recession volume was highly reproducible. For all replicas, the 3D optical method showed small standard deviations and intraclass correlation coefficients between 0.997 and 0.999. CONCLUSIONS: This new method allows the reproducible volumetric evaluation of gingival recession marks on stone replicas. Additional clinical trials are necessary to confirm these in vitro findings. This method allows the operator to control the volumetric progression of periodontal soft tissue, for example, after root coverage procedures and to detect relapses at an early stage.

Clinical, therapeutic and prognostic features of osteosarcoma of the jaws - experience of 36 cases.

INTRODUCTION: Osteosarcoma of the jaws (OSJ) differs from osteosarcoma of other skeletal regions due to later development, a high mortality associated with the local disease, fewer incidences of metastases and its extreme rarity. In regard to clinical and pathological parameters as well as therapeutic approaches and prognosis, OSJ has not been specifically examined to date. In order to achieve a better understanding of this special malignancy, an evaluation of incidence, treatment and prognosis of patients with OSJ in our department over the past 38 years was conducted. MATERIALS AND METHODS: A retrospective analysis of patients with OSJ between 1972 and 2010 was performed. Information regarding patient characteristics, site of the lesion, main presenting symptoms, latency of initial diagnosis, treatment, histology, local recurrence, development of metastatic disease, duration of follow up and survival was obtained. The data were compared to the literature. RESULTS: Thirty-six patients (2-81 years, mean: 33.9, standard deviation: 21.3) were diagnosed and treated for OSJ (maxillar:mandibular nearly 1:2). Initial symptoms were local swelling (81%) and pain (47%). The latency period between fist symptoms and clinical presentation was 3.7 months (1-24). A radical resection alone was conducted in 15 patients. In nine patients, resection and radiotherapy was used. Resection with chemotherapy was the treatment of choice in seven patients. Five patients received a triple combination of resection, chemo- and radiation therapy. The osteoblastic subtype of osteosarcoma was most frequent (42%). In 15 cases (42%) local recurrences, in two cases (5%) metastasis were seen. Of these patients, 13 died within the observation period. One other patient (3%) died as a result of progressive pulmonary metastasis. A mean total survival rate of 61% could be seen whereas the highest survival rate (80%) was found in patients who were treated with neoadjuvant chemotherapy, radical resection and adjuvant radiation. Positive prognostic factors were a younger age and tumour-free resection margins. DISCUSSION: OSJ is a highly lethal tumour entity. According to the data at hand, therapy should possibly include chemotherapy, radical resection and irradiation. Nevertheless, due to the rarity of OSJ, information remains limited and the treatment of choice should be within the focus of clinical multi-centre studies.