Clarissa Precht

Impact of Dental Implant Surface Modifications on Osseointegration.

Objective. The aim of this paper is to review different surface modifications of dental implants and their effect on osseointegration. Common marketed as well as experimental surface modifications are discussed. Discussion. The major challenge for contemporary dental implantologists is to provide oral rehabilitation to patients with healthy bone conditions asking for rapid loading protocols or to patients with quantitatively or qualitatively compromised bone. These charging conditions require advances in implant surface design. The elucidation of bone healing physiology has driven investigators to engineer implant surfaces that closely mimic natural bone characteristics. This paper provides a comprehensive overview of surface modifications that beneficially alter the topography, hydrophilicity, and outer coating of dental implants in order to enhance osseointegration in healthy as well as in compromised bone. In the first part, this paper discusses dental implants that have been successfully used for a number of years focusing on sandblasting, acid-etching, and hydrophilic surface textures. Hereafter, new techniques like Discrete Crystalline Deposition, laser ablation, and surface coatings with proteins, drugs, or growth factors are presented. Conclusion. Major advancements have been made in developing novel surfaces of dental implants. These innovations set the stage for rehabilitating patients with high success and predictable survival rates even in challenging conditions.

The use of buccal fat pad (BFP) as a pedicled graft in cleft palate surgery

The buccal fat pad (BFP) as pedicled graft was originally used in reconstructing medium sized intraoral defects. Promising results concerning the use of BFP in cleft palate surgery have been published recently. The aim of this article is to report on the use of BFP as a pedicled graft in cleft palate surgery and to discuss promising results for this reconstructive surgical concept. A retrospective evaluation of 24 patients who had BFP pedicled flaps used for the prevention and repair of Type III (Pittsburgh Fistula Classification) cleft palate fistulas, to obstruct the retromolar space of Ernst and in case of wide clefts, from 2005 to 2010, was conducted. In all cleft palate patients, the recipient area fully epithelialized within 4 weeks or less. No recurrence was seen and the donor site healed well without aesthetic or significant functional impairment. This series confirms the excellent and predictable healing of BFP intraorally and the minimal morbidity associated with the use of such grafts. The results of this study allow the authors to recommend that the BFP pedicled flap is considered as a reliable alternative procedure to expand the therapeutic options. The BFP graft provides an advantage in reconstructive cleft palate surgery.

ABO Blood Group IgM Isoagglutinins Interact with Tumor-Associated O-Glycan Structures in Pancreatic Cancer

Purpose: The ABO gene locus is associated with the risk of developing pancreatic ductal adenocarcinoma (PDAC) resulting in an increased incidence in individuals with non-O blood groups. Up to 90% of PDAC specimens display alterations in mucin type O-GalNAc glycosylation. Because aberrant O-GalNAc glycans (Tn and T antigen) are structurally related to blood group A and B glycans, we investigated the role of IgM isoagglutinins in PDAC. Experimental Design: Binding studies of IgM isoagglutinins toward blood group A, B, Tn antigen, and T antigen glycoconjugates from patients with PDAC and healthy individuals were conducted. Isoagglutinin titers and total IgM were compared between patients with PDAC and control group. An anti-A antibody was used for immunoprecipitation of aberrant O-glycosylated tumor proteins and subsequent mass spectromic analysis. Results: We found that IgM isoagglutinins bind blood group antigens, Tn and T glycoconjugates as well as tumor-derived glycoproteins. Blood group A isoagglutinins exhibited a strong binding toward blood group B antigen and T antigen, whereas blood group B showed binding to blood group A antigen and Tn antigen. Furthermore, we confirmed a decreased frequency in individuals with blood group O and observed a significant decrease of IgM isoagglutinin titers in PDAC sera compared with control sera, whereas total IgM levels were unaltered. We identified new PDAC-derived O-GalNAc glycoproteins by mass spectrometry using a blood group A-specific antibody. Conclusion: Our data elucidated a novel interaction of blood group IgM isoagglutinins and PDAC O-GalNAc glycoproteins that may contribute to the pathogenesis and progression of pancreatic cancer. Clin Cancer Res; 20(23); 6117–26. ©2014 AACR.

Lack of evidence for prognostic value of epidermal growth factor receptor intron-1 CA repeats for oral carcinomas.

Epidermal growth factor receptor (EGFR) expression is altered in several malignancies, including oral squamous cell carcinoma. A CA-repeat polymorphism in intron-1 (CA-SSR-1) of the EGFR gene is reported to influence EGFR expression and is associated with features of various solid tumors and outcomes of cancer patients. In the present study we evaluated the influence of length and zygosity of CA-SSR-1 on the survival of patients with oral squamous cell carcinoma. The length and zygosity of CA-SSR-1 was obtained through microsatellite analysis in 91 patients with oral cancer, who were treated in the Department of Oral and Maxillofacial Surgery of the University Medical Centre Hamburg Eppendorf, Germany, during the years 1998-2008. Follow up was conducted until 2016. Outcome measures were age, gender, tumor stage, occurrence of metastases, and date of recurrence or death. Statistical analysis was conducted using the chi-square test and the log-rank test. Neither length nor zygosity of the CA-SSR-1 in patients with oral squamous cell carcinoma was significantly correlated with sex, age, tumor size, tumor localization, lymph node involvement, metastasis status, disease-free survival, or overall survival. Length and zygosity of the CA-SSR-1 polymorphism in EGFR is not able to serve as a prognostic biomarker in White European patients with oral squamous cell carcinoma.

Changes in surface characteristics of titanium and zirconia after surface treatment with ultraviolet light or non-thermal plasma

Positive effects of irradiation with ultraviolet (UV) light or treatment with non-thermal plasma on titanium and zirconia surfaces have been described in various studies. The aim of this study was to assess and compare the changes in the physicochemical surface conditions of titanium and zirconia surfaces after a short treatment with UV light or with non-thermal plasmas of argon or oxygen. Titanium and zirconia samples with moderately rough surfaces were treated for 12 min either in a UV-light oven or in a non-thermal plasma reactor that generates non-thermal plasmas of oxygen or argon. Changes in surface conditions were assessed by confocal microscopy, dynamic contact angle measurement, and X-ray photoelectron spectroscopy (XPS). No changes in roughness occurred. Ultraviolet irradiation and non-thermal plasma significantly increased the wettability of the titanium and zirconia surfaces. X-ray photoelectron spectroscopy showed an increase of oxygen and a significant decrease of carbon after treatment with either method. Thus, ultraviolet light and non-thermal plasma were found to be able to improve the chemical surface conditions of titanium and zirconia following a short exposure time. However, further in vitro and in vivo studies are needed to determine the relevance of the results.

Pin-up Glottoplasty: Feasibility Study of a Novel Approach Medializing or Lateralizing Immobile Vocal Folds

Principles in medializing and lateralizing vocal folds have not changed a lot within the last decades (Isshiki et al, 1974; Bruenings, 1911). We present a feasibility study for a completely new approach to perform medialization and lateralization of immobile vocal folds. The method was tested on 20 human larynges by inserting a 21G needle into the vocal fold, medializing (or, in other cases, lateralizing) the vocal cord and fixing the needle at the cricoid cartilage posteriorly. The anterior and posterior fixation points of the needle allow for a stable positioning of the needle, which we consider necessary in both cases of medialization or lateralization. The needle position was examined visually as well as three-dimensionally via cone beam computed tomography.

Biocompatibility and Osseointegration of Titanium Implants with a Silver-Doped Polysiloxane Coating: An In Vivo Pig Model

PURPOSE To test the antimicrobial properties, surface topography, reaction of surrounding tissue (biocompatibility), and osseointegration of ultrathin implant surfaces containing polysiloxane and nanoscaled silver particles. MATERIALS AND METHODS Implants with polysiloxane coating and nanoscaled silver particles (Ag/SiOxCy; HyProtect, Bio-Gate) were compared with implants with polysiloxane coating alone and with noncoated (grit-blasted and acid-etched) implants. A total of 72 implants were inserted into the calvaria of eight domestic pigs (nine implants each, three of each type). After 3 months, histologic sections were evaluated for inflammatory cell infiltration and bone implant contact. RESULTS Roughness parameters did not differ between all three implant types. The Ag/SiOxCy coating exhibited a good antimicrobial effect in vitro and no sign of inflammatory cell infiltration in vivo. The noncoated implants demonstrated 10.85% and 14.48% more bone contact than the polysiloxane-coated implants (P = .003) and the Ag/SiOxCy‑coated implants (P ≤ .001), respectively. Osseointegration was not significantly different between the Ag/SiOxCy‑coated and polysiloxane-coated implants (P = .72). CONCLUSION The osseointegration capability of the Ag/SiOxCy-coated implants was equal to that of the polysiloxane-coated implants but less than that of the grit-blasted and acid-etched implants. Because of the biocompatibility of the polysiloxane coating, further studies should be conducted in load-bearing models and in the oral cavity to investigate the antimicrobial effect of the embedded silver clusters.

Accuracy of Bone Measurements in the Vicinity of Titanium Implants in CBCT Data Sets: A Comparison of Radiological and Histological Findings in Minipigs

Purpose The aim of this animal study was the determination of accuracy of bone measurements in CBCT (cone-beam computed tomography) in close proximity to titanium implants. Material and Methods Titanium implants were inserted in eight Göttingen minipigs. 60 implants were evaluated histologically in ground section specimen and radiologically in CBCT in regard to thickness of the buccal bone. With random intercept models, the difference of histologic measurements and CBCT measurements of bone thickness was calculated. Results The mean histological thickness of the buccal bone was 5.09 mm (CI 4.11–6.08 mm). The four raters measured slightly less bone in CBCT than it was found in histology. The random effect was not significant (p value 1.000). Therefore, the Intraclass Correlation Coefficient (ICC) was 98.65% (CI 100.00–96.99%). Conclusion CBCT is an accurate technique to measure even thin bone structures in the vicinity of titanium implants.

The benefit of abdominal sonography and chest X-ray for staging oral squamous cell carcinomas in stages UICC I and II

PURPOSE The purpose of this study was to evaluate how often distant metastases occur in localized oral squamous cell carcinomas (OSCC). The investigators hypothesize that abdominal sonography and chest X-ray may not be necessary for initial staging of early oral squamous cell carcinoma in UICC stage I/II. MATERIAL AND METHODS The investigators implemented a retrospective study. The study collective was composed of 124 patients with OSCC, who were treated in the department of oral and maxillofacial surgery during the years 2011-2015 at the University Medical Center Hamburg Eppendorf, Germany. We focused on age, gender, date of diagnosis, tumour stage (clinical and pathological), HPV status, occurrence of metastases, recurrences, date and frequency of staging and restaging (abdominal sonography, chest X-ray, CT Abdomen/Thorax, PET CT), follow up time and date of death. Descriptive and bivariate statistics were computed (chi-square test) and the P value was set at .05. RESULTS 19 distant metastases were found in 13 out of 124 patients (10.48%). Of those 20 metastases 5 were found in the liver (26.32%), 11 in the lung (57.89%) and 4 in the bone (15.79%). Hepatic metastases co-occurred in every case with pulmonary metastases. In one case bone metastases occurred without the presence of pulmonary metastases. There was no significant correlation of metastasis rate to T stage. But distant metastases were solely found in node positive patients. This was significant for pulmonary metastases, not for liver metastases. Only one out of 11 pulmonary metastases was diagnosed by chest X-ray. CONCLUSION Abdominal sonography and chest X-ray can be omitted as a standard procedure in staging of localized node negative oral squamous cell carcinoma. A thoracic CT including the liver should be performed in patients with suspected lymph nodes metastases in the neck on CT. A skeletal scintigraphy or alternatively a PET/PET-CT should be added if there are signs and symptoms suspicious for bone metastases.