German S3 guideline on the use of dental ceramic implants.

PURPOSE: Based on the excellent long-term data, dental implants made of titanium are considered the international implantological standard for replacing missing teeth. However, ceramic implants made of zirconia (ZrO2) have experienced a renaissance in the last 15 years due to constant innovations in materials and products, with material properties and soft tissue- and osseointegration behavior comparable to those of titanium. However, one limitation concerning ceramic implants is the lack of reliable long-term data, especially in the case of two-piece implant systems. As there is an increasing demand for ceramic implants from practitioners and patients, the German Society for Implantology (DGI) has decided to develop a guideline on the use of dental ceramic implants at the highest available evidence level with the involvement of experts in this field. METHODS: Statements and recommendations were prepared after conducting a systematic literature search and an independent assessment process involving the relevant clinical literature from 2008 to 2021. The adopted recommendations and statements are summarized in this guideline. RESULTS AND CONCLUSIONS: It confirms the feasible use of one-piece zirconia implants as an addendum/alternative to titanium implants. No final conclusion regarding the application of two-piece ceramic implant systems could be drawn on the basis of the existing data, thus its use can only be recommended after the patient has been informed in detail about the lack of long-term clinical data.

Oral rehabilitation with dental implants in irradiated patients: a meta-analysis on implant survival.

OBJECTIVES: The aim of this comprehensive literature review is to provide recommendations and guidelines for dental implant therapy in patients with a history of radiation in the head and neck region. For the first time, a meta-analysis comparing the implant survival in irradiated and non-irradiated patients was performed. MATERIAL AND METHODS: An extensive electronic search in the electronic databases of the National Library of Medicine was conducted for articles published between January 1990 and January 2013 to identify literature presenting survival data on the topic of dental implants in patients receiving radiotherapy for head and neck cancer. Review and meta-analysis were performed according to Preferred Reporting Items for Systematic Review and Meta-Analyses statement. For meta-analysis, only studies with a mean follow-up of at least 5 years were included. RESULTS: After screening 529 abstracts from the electronic database, we included 31 studies in qualitative and 8 in quantitative synthesis. The mean implant survival rate of all examined studies was 83 % (range, 34-100 %). Meta-analysis of the current literature (2007-2013) revealed no statistically significant difference in implant survival between non-irradiated native bone and irradiated native bone (odds ratio [OR], 1.44; confidence interval [CI], 0.67-3.1). In contrast, meta-analysis of the literature of the years 1990-2006 showed a significant difference in implant survival between non-irradiated and irradiated patients ([OR], 2.12; [CI], 1.69-2.65) with a higher implant survival in the non-irradiated bone. Meta-analysis of the implant survival regarding bone origin indicated a statistically significant higher implant survival in the irradiated native bone compared to the irradiated grafted bone ([OR], 1.82; [CI], 1.14-2.90). CONCLUSIONS: Within the limits of this meta-analytic approach to the literature, this study describes for the first time a comparable implant survival in non-irradiated and irradiated native bone in the current literature. Grafted bone combined with radiotherapy was identified as a negative prognostic factor on implant survival. CLINICAL RELEVANCE: The evolution of implant hardware and improvement of treatment strategies during the last years have affirmed dental implant-supported concepts as a valuable treatment option for patients with a history of radiation in the head and neck region.

[Medically compromised patients in the dental office: demographics and progress in health care]. / Risikopatienten in der zahnärztlichen Praxis : Demografie und medizinischer Fortschritt.

Due to changing demographics in our society, there are an increasing number of patients with risk factors presenting for dental care. Unfortunately valid screening instruments to identify these patients are lacking. Especially in elderly patients, there is often an association between the high number of prescribed medications and oral symptoms. Using supportive therapy in oncology (e.g., radio(chemo)therapy) as an example, the role of modern dentistry and its interaction with general medicine is illustrated. Modern substances, e.g., antiangiogenetics, with still unknown side effects represent challenging new developments in the field of oral medicine. Even with some examples of positive representation of patients with risk factors in the health systems, e.g., § 28 SGB V, it is clear that the pressure on the costs in the health systems leads to an undertreatment of patients with risk factors. Only by adapting dental and postgraduate training with respect to these aspects, together with better financial reimbursement of the additional efforts, will this trend be overcome.

Functional rehabilitation of mandibular continuity defects using autologous bone and dental implants - prognostic value of bone origin, radiation therapy and implant dimensions.

AIM: The aim of this retrospective study was to investigate prognostic parameters for the rehabilitation of mandibular continuity defects with free autologous bone and dental implants for patients after intraoral squamous cell carcinoma. METHODS: Following potential prognostic factors for implant survival were analyzed: bony bed (local bone versus augmented iliac crest bone), radiation dose (no radiation, <50 Gy, >or=50 Gy) and implant dimensions. Kaplan-Meier survival estimates of the inserted implants were performed. RESULTS: After 5 years, the cumulative survival rate of all investigated implants was 82.6%. Dental implantation into augmented bone resulted in a significantly lower survival rate (78.4%), compared to original local bone (92.8%). Modifications of implant dimensions as well as radiation therapy showed no significant impact on implant survival. CONCLUSION: For the investigated compromised collective, our results reveal a satisfactory long-term survival rate of dental implants even in augmented bone and underline the value of dental implantation for the functional rehabilitation of cancer patients.

Ultrasound transmission velocity for noninvasive evaluation of jaw bone quality in vivo before dental implantation.

For the insertion of dental implants, mechanical bone properties at the implantation site have great impact both for therapeutic regimes as well as for the overall long-term success, making a reliable method for the preoperative assessment of the bone quality desirable. Ultrasound transmission velocity (UTV) has been introduced as a noninvasive method to analyze mechanical properties of bone. The aim of this study was the first intra-oral in vivo assessment of alveolar crest UTV values of edentulous jaws. Partly or fully edentulous patients (n = 108) were enrolled in this study, taking into account possible influence factors that affect bone quality (osteoporosis, radiation therapy). Six intra-oral measurement points were used: left side region, right side region and frontal region, for upper and lower jaw, respectively. Ultrasound transmission velocity values were measured bicortically (in bucco-oral direction) and correlated to sex, age, measurement site and history of osteoporosis or radiation therapy. We found a minimum mouth opening of 30 mm, as well as a residual alveolar ridge height of 8 mm as thresholds for a reliable intra-oral placement of the device. Xerostomia was no contraindication. Assessment of intra-oral UTV showed significantly higher values both for mandibular side regions (female 1713 +/- 153 m/s, male 1734 +/- 221 m/s) and the maxillary frontal region (female 1665 +/- 189 m/s, male 1648 +/- 82 m/s) than for maxillary side regions (female 1538 +/- 177 m/s, male 1583 +/- 90 m/s). These data were even more clarified by intra-individual correlation of upper and lower jaw side region UTV values. We found no correlation between assessed UTV values and the variables sex, age, osteoporosis or radiation therapy. The use of a small UTV device in this study allowed the recording of intra-oral UTV values in a large and heterogeneous patient collective for the first time. Assessment of alveolar-ridge UTV might offer the possibility to identify critical bone quality before implantation or to monitor bone healing (mineralization) after augmentation procedures.

Dental implantation: ultrasound transmission velocity to evaluate critical bone quality--an animal model.

PURPOSE: In dental implantology, preoperative evaluation of bone quality is an important aspect for the long-term success of the treatment. The insertion of implants into regions with a great portion of poorly mineralised cancellous bone, in particular, increases the risk of subsequent implant failure. The measurement of Ultrasound Transmission Velocity (UTV) proved to be a non-invasive and valid method for the assessment of mechanical properties of bone. The aim of this study was to correlate conventional histomorphometric bone properties with UTV-values from mandibular and iliac crest bone specimens in an animal model. MATERIALS AND METHODS: 12 native (no sample preparation) porcine specimens from mandibular bone and 14 from iliac crest bone, respectively, were studied both by UTV measurement and by conventional histomorphometry. UTV-values were measured bicortically by three different investigators four times at each site. Bone samples from identical sites were obtained and ground down to a thickness of approx. 50 microm. Transmission light microscopy was used to assess the overall percentage of mineralised bone. Mineral bone density less than 40% was defined as "critical". RESULTS: The median bone density was 43 % for mandibular bone and 23% for iliac crest bone, respectively. The median UTV values of the mandible (1756 m/sec) were significantly higher than those of the iliac crest specimens (1613 m/sec). Intra-individual correlation testing illustrates a positive, statistically significant correlation between presurgical UTV measurement and the grade of mineralisation (r=0.54). ROC analysis defined a UTV breakpoint of 1767 m/sec to identify critical bone with a sensitivity of 75%. CONCLUSION: In this ex-vivo model, UTV measurements have proven to be a reliable method for identifying critical bone quality prior to implantation.

[Systematic qualitative histology of enossal implants with anodically oxidised surfaces]. / Systematische qualitative Histologie von enossalen Implantaten mit anodisch oxidierten Oberflächen.

Histological analysis of dental implants is often quantified by calculating the bone-implant contact rate (bone volume/total volume), whereas qualitative aspects like osteoconduction are underrepresented. The aim of this study was to focus on the micro-architectural properties of the bone-implant contact under physiologic loading using a systematic analysis of these characteristics. In 16 Beagle dogs we inserted 6 different types of dental implants in the hard bone of the mandible and the soft bone of the maxilla. After a healing period of two months the implants were loaded for three months and then histologically analysed. For the metric evaluation of qualitative histological aspects 12 examiners answered pivotal questions: 1. Is the implant functional sufficient? 2. Do you see close contact to bone, were bone is present? 3. Is the amount of bone at the implant at least similar to the peripheral bone? 4. Is the bone to implant contact homogenous? 5. Does the bone show a functional architecture? 6. Do you find osseoconductive bone apposition at the crestal and apical border? A superiority of anodic oxidized surfaces can be seen in questions 1, 2 and 3 mainly for the comparison of identical macrodesigns (MkIII). The potential for osseoconductivity (questions 4 and 5) shows a tendency for significant differences for the ZL Ticer implant. Homogenous bone to implant contact is rarely found, in contrast to rather positive implant function ratings. This suggests the existence of an optimum in the bone to implant contact rate. Bone to implant contact rate as an isolated quantitative parameter should in future be completed by a systematic, standardised and blinded analysis of qualitative properties.

Prospective study of the long term change of the oral flora after radiation therapy.

OBJECTIVES: The aim of this prospective study was to evaluate the long term change in oral pathogens following radiation therapy. METHODS: Twenty-two patients with planned radiation therapy (>30 Gy) of head and neck squamous cell carcinoma were included. Before radiation therapy, after 3, 6, and 12 months samples from the deepest periodontal pocket were drawn. Five major periodontal pathogens were studied using DNA probes (Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Bacteriodes forsythus, Treponema denticola). Stimulated saliva was sampled for the microbiologic study of caries pathogens (streptococci and lactobacilli). Plaque index and decayed, missing, filled tooth surfaces (DMF-S) were recorded. RESULTS: A normalisation of the caries bacteria is not found correlating to a significant increase in the number of affected teeth (DMF-S) from 80.7 to 88.5 after 12 months. The plaque index remained unchanged. The incidence of periodontal pathogens did not significantly change during the follow up. CONCLUSION: In contrast to radiation caries there seems to be no microbiological evidence for "radiation periodontitis". Despite of the intensive oral hygiene no reduction of the high number of caries pathogens is found, which leads to a high risk of tooth decay even 12 months after radiation.

[Experimental study of osseointegration of zirconium and titanium dental implants].

In an experiment performed on pigs, methods of light and scanning electron microscopy were used to study the interaction of zirconium and titanium dental implants with bone 6 months following their insertion. Distinct features of integration of both implant types with bone structures were detected. Sites of direct contact of bone structures with metal were found to undergo constant remodeling according to biochemical and metabolic conditions in each zone of an implant surface. Statistically the degree of interactive properties of zirconium implants significantly exceeded similar parameter for titanium screws. Along the perimeter of the zones of bone contact with zirconium implants greater numbers of forming and formed bone areas were revealed as compared to the zones of bone contact with titanium implants, where erosion lacunae were more numerous. The complex of research methods used in this study have not revealed distinct changes in the structure of osteocytes, located in immediate proximity to the metal surface in comparison with more distant sites in the bone.

[Fasciitis nodularis pseudosarcomatosa. A difficult differential diagnosis in the head-neck area]. / Fasciitis nodularis pseudosarcomatosa. Eine schwierige Differenzialdiagnose im Kopf-Hals-Bereich.

INTRODUCTION: Nodular fasciitis (nF) was first described in 1955 by Konwaler et al. as a benign fibroblastic proliferation. The onset of the disease occurs suddenly as a solitary tumor reaching a size of 10 to 50 mm in a few weeks. Relapse is rare and spontaneous remission frequent. The literature points out histologic similarities to a sarcoma. CASE: The 57 year old female patient presented a spheroid, coarse, nonadherent, slightly painful tumor of the left paramandibular region. The history was inconspicuous. The B-scan sonography revealed a spheroid, anechoic, defined mass of 10-11 mm. The palpatory dimension increased noticeably during the following 2 weeks. Under local anesthesia the suspected lymph node was exposed via intraoral approach. Intraoperatively a non-capsulated, coarse, adherent, spheroid node of 25 mm was resected subtotally to preserve the marginal branch of the facial nerve. Histologically a fibroblastic cell-rich proliferation with mucoid milieu and few mitosis was found. No atypical cells or nuclei were observed and the proliferation reached fascial parts. DISCUSSION: Based on clinical findings the diagnosis nF cannot be proven. Ultrasound and clinical findings suppose a lymphadenopathia, whereas the dynamics points out a malignant tumor. Therefore, histologic assurance after diagnosis is mandatory. In case of vulnerable anatomic structures in vicinity, the absence of a capsule should lead to partial resection despite of a total excision. The histology plays a primary role to avoid surgical overtherapy.

Long-term oral Candida colonization, mucositis and salivary function after head and neck radiotherapy.

The aim of this study was to follow the long-term effects of radiation therapy of head and neck malignancies on oral yeast colonization, mucositis and salivary function. Included in this prospective study were 32 patients with intended radiation therapy of a malignancy of the head and neck. In all patients the salivary glands lay within the radiation field and the patients had at least five teeth. The first examination was performed after oral hygiene instruction and removal of questionable teeth before the start of radiotherapy. The following examinations were conducted after 3, 6, 9 and 12 months. Together with the quantitative determination of Candida colonization, three "mucositis" variables were assessed: (1) examiner-rated mucositis score (LENT/SOMA), (2) patient-rated mucositis symptoms, and (3) scintigraphic salivary excretion fraction. The maximum Candida colonization was found 6 months after radiation therapy and this declined to above normal values after 12 months. Salivary flow was at a minimum 6 months after radiation therapy and had slightly recovered by 12 months. Examiner-rated mucositis and patient-rated xerostomia showed no significant recovery after 6 or 12 months. The results of this study show slight recovery of the oral ecological system. Although the causal role of a single parameter is not clear, persistently elevated Candida colonization should be taken into account therapeutically.

Validation of three-dimensional surface characterising methods: scanning electron microscopy and confocal laser scanning microscopy.

Surface characteristics of enosseous titanium implants have been known to influence the quality of osseointegration. Parameters recommended for metrical analysis should be supplemented by a topographical description. In this study, Ra values obtained by established tactile and optical profilometric methods are correlated with those obtained by stereo scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). As test specimens, standardised CVD diamond-coated titanium alloys with different microwave coating power ranging from 2,000 to 3,000 W were used. A non-CVD-coated corund grit-blasted specimen (NC) was used as reference. After coating with a CVD, power of 2,000 W Ra ranges from 4.33 to 5.69 microm depending on the method used. With increasing power of the coating process, the amplitude of the surface roughness is significantly increased to 4.53 to 6.89 microm. Ra values of the same sample obtained by different methods are also significantly different (p = 0.001). Compared with the established methods of tactile and optical profilometry, SEM and CLSM offer valid data on the surface roughness accompanied by a topographical imaging. In future studies, the underlying method should be specified to interpret roughness values correctly, as not every method is suitable for each specimen and values obtained by different methods vary extremely.

[Therapy monitoring with 2-(18F)-FDG positron emission tomography after neoadjuvant radiation treatment of mouth carcinoma]. / Therapiemonitoring mittels 2-[18F]-FDG-Positronenemissionstomographie nach neoadjuvanter Strahlenbehandlung des Mundhöhlenkarzinoms.

BACKGROUND: Combined protocols of radiation therapy and surgical resection, as applied in advanced oral cancer, rely on objective and early assessment of treatment response to radiation therapy. Non-responders require immediate radical salvage surgery even in spite of substantial operative risks, while complete or subtotal response may give reasons for continuing the conservative approach. Therefore, we investigated radiation response by FDG-PET for early monitoring of oral cancer. PATIENTS AND METHODS: In 30 patients with advanced stages of oral cancer (Table 1), FDG-PET (Siemens, ECAT EXACT 922) was performed within 4 weeks after completion of preoperative radiation therapy (36 Gy). SUV of tumor regions were compared to the histologic degree of tumor regression in complete resection specimens. Statistic evaluation included correlation analysis of SUV vs tumor regression and ROC analysis for SUV cut-off values. RESULTS: While low FDG accumulation was found in tumors with histological complete remission (2.3 +/- 0.4) as well as in cases of residual tumor (3.4 +/- 1.8), high FDG uptake was a rather specific indicator of vital tumor tissue (Figure 2). Significant correlation (p = 0.045) between postradiotherapeutic FDG-uptake and histological tumor regression was recognized. A SUV > 2.75 as a clinically practicable threshold value for the identification of residual vital tumor resulted in a specificity of 88%, sensitivity of 68%, a positive predictive value of 94% and a negative predictive value of 50% (Figure 3). Based on our actual follow-up data we could not confirm a significant correlation between postradiotherapeutic SUV and patients' survival. CONCLUSION: Within a standardized protocol, FDG-PET recognize treatment response to radiation therapy in oral squamous cell carcinoma with a reasonable specificity and thus provides a basis for further therapeutic decisions. An increased SUV (> 2.75) may be the rational to justify an aggressive surgical approach even when patients face substantial surgical or anesthesiological risk. However, the posttherapeutic pattern of glucose uptake varies with the applied treatment modalities and has to be explored for the protocol applied.

[Chronic radiation effects on dental hard tissue (radiation caries). Classification and therapeutic strategies]. / Chronische Strahlenfolgen an den Zahnhartgeweben ("Strahlenkaries"). Klassifikation und Behandlungsansätze.

OBJECTIVES: Since the first description of rapid destruction of dental hard tissues following head and neck radiotherapy 80 years ago, "radiation caries" is an established clinical finding. The internationally accepted clinical evaluation score RTOG/EORTC however is lacking a classification of this frequent radiogenic alteration. MATERIAL AND METHODS: Medical records, data and images of radiation effects on the teeth of more than 1,500 patients, who underwent periradiotherapeutic care, were analyzed. Macroscopic alterations regarding the grade of late lesions of tooth crowns were used for a classification into 4 grades according to the RTOG/EORTC guidelines. RESULTS: No early radiation effects were found by macroscopic inspection. In the first 90 days following radiotherapy 1/3 of the patients complained of reversible hypersensitivity, which may be related to a temporary hyperemia of the pulp. It was possible to classify radiation caries as a late radiation effect on a graded scale as known from RTOG/EORTC for other organ systems. This is a prerequisite for the integration of radiation caries into the international nomenclature of the RTOG/EORTC classification. CONCLUSIONS: The documentation of early radiation effects on dental hard tissues seems to be neglectable. On the other hand the documentation of Late radiation effects has a high clinical impact. The identification of an initial lesion at the high-risk areas of the neck and incisal part of the tooth can lead to a successful therapy as a major prerequisite for orofacial rehabilitation. An internationally standardized documentation is a basis for the evaluation of the side effects of radiooncotic therapy as well as the effectiveness of protective and supportive procedures.

Prophylaxis of radiogenic sialadenitis and mucositis by coumarin/troxerutine in patients with head and neck cancer--a prospective,randomized, placebo-controlled, double-blind study.

OBJECTIVE: To study the efficacy of coumarin/troxerutine for the protection of salivary glands and mucosa during irradiation. DESIGN: Prospective, randomized, placebo-controlled, double-blind trial. SETTING: University hospital, Germany. PATIENTS: 48 patients who had radiotherapy to the head and neck. MAIN OUTCOME MEASURES: Salivary gland scintigraphy and acute side-effects of radiotherapy (Radiation Therapy Oncology Group (RTOG) score). RESULTS: 23 patients (11 experimental, 12 placebo) completed the study. The global efficacy measure combining scintigraphy and RTOG score favoured the experimental arm (P=0.07). The RTOG score showed significantly fewer acute side-effects of radiation in the experimental arm (P<0.05). CONCLUSION: The results suggest that coumarin/troxerutine have a favourable effect in the treatment of radiogenic sialadenitis and mucositis.