Dental phobia is no contraindication for oral implant therapy

OBJECTIVES Dental phobia is a psychological disease and a possible contraindication for implant therapy. The study aimed to show that implant therapy in dental-phobic patients (DP, test group) after adequate psychological and dental pretreatment (PDPT) is successfully possible and results in a similar implant prognosis as in nonfearful patients (NF, control group). METHOD AND MATERIALS 15 DP with PDPT and 15 NF were treated with dental implants and were re-evaluated 2 to 4 years after denture-mounting regarding: alteration of dental anxiety (Hierarchical Anxiety Questionnaire [HAQ], Visual Analog Scale [VAS]), patient satisfaction and compliance, implant success, and peri-implant health. Statistical tests of non-inferiority DP versus NF were performed with Hodges-Lehmann estimators and respective one-sided 97.5% confidence intervals of Moses, and pairwise testings with Mann-Whitney test. RESULTS The DP test group rated its anxiety significantly lower at follow- up than at baseline (PHAQ < .001). However, at follow-up, anxiety was still higher in DP than in NF (PHAQ = .046; PVAS < .001). Implant success at follow-up was 100%. Oral health was equally good in DP and NF patients. At follow-up, all patients were satisfied with implant therapy, but compliance was better for NF (100%) than for DP (73% dental checkup; 67% dental hygienist). CONCLUSION Implant therapy can be successfully performed in DP patients with PDPT as phobia is not negatively influenced by the invasive implant therapy. However, motivation for professional maintenance programs remains challenging.

In vitro precision of fit of computer-aided design and computer-aided manufacturing titanium and zirconium dioxide bars

OBJECTIVES Optical scanners combined with computer-aided design and computer-aided manufacturing (CAD/CAM) technology provide high accuracy in the fabrication of titanium (TIT) and zirconium dioxide (ZrO) bars. The aim of this study was to compare the precision of fit of CAD/CAM TIT bars produced with a photogrammetric and a laser scanner. METHODS Twenty rigid CAD/CAM bars were fabricated on one single edentulous master cast with 6 implants in the positions of the second premolars, canines and central incisors. A photogrammetric scanner (P) provided digitized data for TIT-P (n=5) while a laser scanner (L) was used for TIT-L (n=5). The control groups consisted of soldered gold bars (gold, n=5) and ZrO-P with similar bar design. Median vertical distance between implant and bar platforms from non-tightened implants (one-screw test) was calculated from mesial, buccal and distal scanning electron microscope measurements. RESULTS Vertical microgaps were not significantly different between TIT-P (median 16μm; 95% CI 10-27μm) and TIT-L (25μm; 13-32μm). Gold (49μm; 12-69μm) had higher values than TIT-P (p=0.001) and TIT-L (p=0.008), while ZrO-P (35μm; 17-55μm) exhibited higher values than TIT-P (p=0.023). Misfit values increased in all groups from implant position 23 (3 units) to 15 (10 units), while in gold and TIT-P values decreased from implant 11 toward the most distal implant 15. SIGNIFICANCE CAD/CAM titanium bars showed high precision of fit using photogrammetric and laser scanners. In comparison, the misfit of ZrO bars (CAM/CAM, photogrammetric scanner) and soldered gold bars was statistically higher but values were clinically acceptable.

Patients with oral tumors. Part 2: Quality of life after treatment with resection prostheses. Resection prosthetics: evaluation of quality of life

In the present study, the oral health-related quality of life of 18 patients (13 men and 5 women) was evaluated using validated questionnaires as proposed by the European Organization of Research and Treatment of Cancer (EORTC). The patients belonged to a cohort of 48 patients, whose prosthetic treatment was performed during the years 2004-2007. In the course of tumor resection, 12 patients underwent graft surgery and 14 patients radiotherapy. One patient required a nasal epithesis since resection of the nose became necessary. Five patients underwent a full block resection of the mandible, and tumor resection in 3 patients resulted in a large oronasal communication. Prosthetic rehabilitation was performed in all patients, and the follow-up period with regular care covered a minimum of 3 years. Eleven patients received dental implants for better support and retention of the prostheses. In spite of compromised oral conditions, functional restrictions, and some difficulties with the prostheses, the answers to the questionnaire were quite positive. The majority judged their general health as good or even excellent. The subjective perception of the patients may contradict the objective view by the dentist. In fact, the individual patient's history and experience provide a better understanding of the impact of oral tumors on daily life. The overall assessment identified 4 items that were perceived as major problems by all patients: swallowing solid food, dry mouth, limited mouth opening, and appearance. Prosthetic rehabilitation has only a limited influence on such problems.

Patients with oral tumors. Part 1: Prosthetic rehabilitation following tumor resection. Resection prosthetics: surgery, implants and prosthetic treatment

The present study reports on the surgical and prosthodontic rehabilitation of 46 patients, 31 male and 15 female, after resection of oral tumors. The treatment was carried out from 2004 to 2007 at the Department of Prosthodontics, University of Bern, with a follow-up time of 3 to 6 years. The average age at diagnosis was 54 years. 76% of all tumors were squamous cell carcinoma, followed by adenocarcinoma. Resection of the tumors including soft and/or hard tissues was performed in all patients. 80% of them additionally underwent radiotherapy and 40% chemotherapy. A full block resection of the mandible was perfomed in 23 patients, and in 10 patients, the tumor resection resulted in an oronasal communication. 29 patients underwent grafting procedures, mostly consisting of a free fibula flap transplant. To enhance the prosthetic treatment outcome and improve the prosthesis stability, a total of 114 implants were placed. However, 14 implants were not loaded because they failed during the healing period or the patient could not complete the final treatment with the prostheses. The survival rate of the implants reached 84.2% after 4 to 5 years. Many patients were only partially dentate before the tumors were detected, and further teeth had to be extracted in the course of the tumor therapy. Altogether, 31 jaws became or remained edentulous. Implants provide stability and may facilitate the adaptation to the denture, but their survival rate was compromised. Mostly, patients were fitted with removable prostheses with obturators in the maxilla and implant-supported complete dentures with bars in the mandible. Although sequelae of tumor resection are similar in many patients, the individual intermaxillary relations, facial morphology and functional capacity vary significantly. Thus, individual management is required for prosthetic rehabilitation.

Virtual implant planning in the edentulous maxilla: criteria for decision making of prosthesis design

OBJECTIVES To evaluate prosthetic parameters in the edentulous anterior maxilla for decision making between fixed and removable implant prosthesis using virtual planning software. MATERIAL AND METHODS CT- or DVT-scans of 43 patients (mean age 62 ± 8 years) with an edentulous maxilla were analyzed with the NobelGuide software. Implants (≥3.5 mm diameter, ≥10 mm length) were virtually placed in the optimal three-dimensional prosthetic position of all maxillary front teeth. Anatomical and prosthetic landmarks, including the cervical crown point (C-Point), the acrylic flange border (F-Point), and the implant-platform buccal-end (I-Point) were defined in each middle section to determine four measuring parameters: (1) acrylic flange height (FLHeight), (2) mucosal coverage (MucCov), (3) crown-Implant distance (CID) and (4) buccal prosthesis profile (ProsthProfile). Based on these parameters, all patients were assigned to one of three classes: (A) MucCov ≤ 0 mm and ProsthProfile≥45(0) allowing for fixed prosthesis, (B) MucCov = 0-5 mm and/or ProsthProfile = 30(0) -45(0) probably allowing for fixed prosthesis, and (C) MucCov ≥ 5 mm and/or ProsthProfile ≤ 30(0) where removable prosthesis is favorable. Statistical analyses included descriptive methods and non-parametric tests. RESULTS Mean values were for FLHeight 10.0 mm, MucCov 5.6 mm, CID 7.4 mm, and ProsthProfile 39.1(0) . Seventy percent of patients fulfilled class C criteria (removable), 21% class B (probably fixed), and 2% class A (fixed), while in 7% (three patients) bone volume was insufficient for implant planning. CONCLUSIONS The proposed classification and virtual planning procedure simplify the decision-making process regarding type of prosthesis and increase predictability of esthetic treatment outcomes. It was demonstrated that in the majority of cases, the space between the prosthetic crown and implant platform had to be filled with prosthetic materials.

Besteht zahnärztlicher Behandlungsbedarf im akutgeriatrischen Krankenhaus?

Aufgrund der großen Präventionserfolge in der Zahnmedizin treten immer mehr Senioren mit Zähnen und Zahnersatz in den Ruhestand ein. Zwischen der Dritten (1997) und Vierten (2005) Deutschen Mundgesundheitsstudie (DMS IV)13 reduzierte sich für die jungen, Zuhause lebenden Senioren (65-74 Jahre) die Zahnlosigkeit auf 22,6 %, die Anzahl der fehlenden Zähne sank von 17,1 auf 14,7 Zähne, aber viele der verbleibenden Zähne wiesen ein hohes parodontales Risiko auf. 72 % suchen den Zahnarzt kontrollorientiert auf. Für die gleiche Altersgruppe konnte mit einer bevölkerungsrepräsentativen Studie aus Pommern (SHIP) gezeigt werden, dass die Kontaktraten zum Zahnarzt im Alter zurückgehen.

Change of the condyle-position in maximum intercuspidation during digital, clinical occlusal analysis

Digital analysis of the occlusal contacts can be performed with the T-scan device (T Scan III, TekScan, Boston, USA). However, the thickness of the interocclusal T-scan sheet (100 μm) may lead to a displacement of the mandible. Thus, the aim of this study was to investigate the impact of the T-scan sheet on the position of the mandibular condyles in maximum intercuspidation. Twenty dentate subjects with healthy jaw function were enrolled in the study. An ultrasonic axiography device was used to measure the position of the condyles. Ten 3D condyle positions in maximum intercuspidation of the teeth were recorded: first the reference position without the sheet, then 3 times without the sheet, 3 times with the sheet, and finally again 3 times without the sheet. There was a statistically significant difference (Wilcoxon matched pairs test) between the condyle positions with and without the interocclusally positioned T-scan sheet (P < 0.0005). The T-scan device lead to a displacement of the condyles of about 1 mm mainly in ventral direction (P = 0.005). Thus, occlusal analysis is not performed in physiological, maximum intercuspidation. This has to be considered when interpreting the measured contact points.

Humoral immunity in tuberculin skin test anergy and its role in high-risk persons exposed to active tuberculosis.

The most common test to identify latent tuberculosis is the tuberculin skin test that detects T cell responses of delayed type hypersensitivity type IV. Since it produces false negative reactions in active tuberculosis or in high-risk persons exposed to tuberculosis patients as shown in this report, we studied antibody profiles to explain the anergy of such responses in high-risk individuals without active infection. Our results showed that humoral immunity against tuberculin, regardless of the result of the tuberculin skin test is important for protection from active tuberculosis and that the presence of high antibody titers is a more reliable indicator of infection latency suggesting that latency can be based on the levels of antibodies together with in vitro proliferation of peripheral blood mononuclear cells in the presence of the purified protein derivative. Importantly, anti-tuberculin IgG antibody levels mediate the anergy described herein, which could also prevent reactivation of disease in high-risk individuals with high antibody titers. Such anti-tuberculin IgG antibodies were also found associated with blocking and/or stimulation of in vitro cultures of PBMC with tuberculin. In this regard, future studies need to establish if immune responses to Mycobacterium tuberculosis can generate a broad spectrum of reactions either toward Th1 responses favoring stimulation by cytokines or by antibodies and those toward diminished responses by Th2 cytokines or blocking by antibodies; possibly involving mechanisms of antibody dependent protection from Mtb by different subclasses of IgG.

Behavioral responses to catecholamine depletion in unmedicated, remitted subjects with bulimia nervosa and healthy subjects

BACKGROUND: Bulimia nervosa (BN) has been associated with dysregulation of the central catecholaminergic system. An instructive way to investigate the relationship between catecholaminergic function and psychiatric disorder has involved behavioral responses to experimental catecholamine depletion (CD). The purpose of this study was to examine a possible catecholaminergic dysfunction in the pathogenesis of bulimia nervosa. METHODS: CD was achieved by oral administration of alpha-methyl-para-tyrosine (AMPT) in 18 remitted female subjects with BN (rBN) and 31 healthy female control subjects. The study design consisted of a randomized, double blind, placebo-controlled crossover, single-site experimental trial. The main outcome measures were bulimic symptoms assessed by the Eating Disorder Examination-Questionnaire. Measures were assessed before and 26, 30, 54, 78, 102 hours after the first AMPT or placebo administration. RESULTS: In the experimental environment (controlled environment with a low level of food cues) rBN subjects had a greater increase in eating disorder symptoms during CD compared with healthy control subjects (condition × diagnosis interaction, p < .05). In the experimental environment, rBN subjects experienced fewer bulimic symptoms than in the natural environment (uncontrolled environment concerning food cues) 36 hours after the first AMPT intake (environment × diagnosis interaction, p < .05). Serum prolactin levels increased significantly, and to a comparable degree across groups, after AMPT administration. CONCLUSIONS: This study suggests that rBN is associated with vulnerability for developing eating disorder symptoms in response to reduced catecholamine neurotransmission after CD. The findings support the notion of catecholaminergic dysfunction as a possible trait abnormality in BN.

Genetic analysis of tumor progression susceptibility in the mouse skin model

In the field of chemical carcinogenesis the use of animal models has proved to be a useful tool in dissecting the multistage process of tumor formation. In this regard the outbred SENCAR mouse has been the strain of choice in the analysis of skin carcinogenesis given its high sensitivity to the chemically induced acquisition of premalignant lesions, papillomas, and the later progression of these lesions into squamous cell carcinomas (SCC).^ The derivation of an inbred strain from the SENCAR stock called SSIN, that in spite of a high sensitivity to the development of papillomas lack the ability to transform these premalignant lesions into SCC, suggested that tumor promotion and progression were under the genetic control of different sets of genes.^ In the present study the nature of susceptibility to tumor progression was investigated. Analysis of F1 hybrids between the outbred SENCAR and SSIN mice suggested that there is at least one dominant gene responsible for susceptibility to tumor progression.^ Later development of another inbred strain from the outbred SENCAR stock, that had sensitivity to both tumor promotion and progression, allowed the formulation of a more accurate genetic model. Using this newly derived line, SENCAR B/Pt. and SSIN it was determined that there is one dominant tumor progression susceptibility gene. Linkage analysis showed that this gene maps to mouse chromosome 14 and it was possible to narrow the region to a 16 cM interval.^ In order to better characterize the nature of the progression susceptibility differences between these two strains, their proliferative pattern was investigated. It was found that SENCAR B/Pt, have an enlarged proliferative compartment with overexpression of cyclin D1, p16 and p21. Further studies showed an aberrant overexpression of TGF-$\beta$ in the susceptible strain, an increase in apoptosis, p53 protein accumulation and early loss of connexin 26. These results taken together suggest that papillomas in the SENCAR B/Pt. mice have higher proliferation and may have an increase in genomic instability, these two factors would contribute to a higher sensitivity to tumor progression. ^

Persistent Deadlock in Multilateral Trade Negotiations: The Case of Doha

The history of the General Agreement on Tariffs and Trade negotiations is full of anecdotes on missed deadlines, failed ministerial conferences, and brinkmanship situations. Tactics such as walking away from the table or sleep-depriving night sessions are legendary in the context of attempting to overcome impasse in negotiations. This article traces and explains the recurrent deadlock in the Doha Round negotiations. It identifies four structural/contextual factors – ideas, institutions, interests, and information – as necessary for understanding and anticipating potential deadlocks. The article also offers a definition of deadlock, and discusses a set of factors highlighted in the international relations literature that explain the existence and persistence of deadlock. With the help of game theory, it then illustrates the challenges faced by actors during trade negotiations. The article concludes by outlining two general scenarios for the Doha Development Agenda and discusses their implications for the World Trade Organization.

Male Dominance in the New Zealand Longfin Eel Population of a New Zealand River: Probable Causes and Implications for Management

The endemic New Zealand longfin eel Anguilla dieffenbachi (hereafter, longfin eel), is overfished, and in southern South Island, New Zealand, rivers have recently become predominated by males. This study examined length and age at sexual differentiation in male eels in the Aparima River catchment (area, 1,375 km(2); mean flow, 20 m(3.)s(-1)) and the sex ratio and distribution of eels throughout the catchment. Longfin eels differentiated into males mostly at lengths from 300 to 460 mm and ages from 10 to 25+ years. Females were rare: Of 738 eels examined for sexual differentiation, 466 were males and 5 were females, and a few others, not examined, were large enough to be female. These counts suggest a male : female ratio among differentiated longfin eels of 68:1. Of 31 differentiated shortfin eels A. australis, less common in the Aparima River, 26 were females. Male longfin eels were distributed throughout the main stern and tributaries; undifferentiated eels were more prevalent in lower and middle reaches and in the main stem than in upper reaches and tributaries. In other studies, male longfin eels predominated commercial catches in the Aparima and four other southernmost rivers, by 2.4:1 to 13.6:1 males to females. The Aparima River had the most skewed sex ratio. Longfin eel catches from the Aparima River will become more male predominated because few sublegal-size females were present. The length-frequency distributions of eels in the present samples and in the commercial catches were truncated just above minimum legal size (about 460 mm), showing that few females escape the fishery. Historically, females predominated these rivers. The recent change in sex ratio is attributable partly to selective harvest of females, and partly to changes in the structure of the population from fishing, such that differentiation into males has been favored. Longevity, delayed sexual maturity, semel-parity, and endemism with restricted range make the longfin eel particularly vulnerable to overfishing.