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Biomedical subjects

K Bitter

Publications and source records attributed to K Bitter.

At least 19 recordsLinked to original sources
PubMed2006

Effects of luting agent and thermocycling on bond strengths to root canal dentine.

AIM: To investigate the effects of luting agent and thermocycling on bond strengths to root canal dentine. METHODOLOGY: Extracted maxillary canines (n =144) were root filled and divided into six groups of 24 teeth each. Fibre posts (FRC Postec) were inserted using six luting agents: Panavia F, Multilink, Variolink II, PermaFlo DC, RelyX Unicem and Clearfil Core. Each root was sliced into six discs (thickness 1 mm) representing the coronal, middle and apical part of the root canal. Push-out tests were performed 24 h after post insertion (n = 12) as well as after thermocycling (5000x; 5-55 degrees C, 30 s) (n = 12). Statistical analysis was conducted using analysis of variance (anova) followed by post-hoc comparisons (Tukey-B). The influence of thermocycling on bond strengths was investigated for each material and region separately using t-tests. RESULTS: The bond strengths were significantly affected by the luting agent (P < 0.001), the root position (P = 0.003) and thermocycling (P < 0.001; three-way anova). RelyX had significantly higher bond strengths compared with all other materials (P < 0.05; Tukey-B). The apical region of the root canal had significantly higher bond strengths compared with the middle and coronal region (P < 0.05; Tukey-B). After thermocycling for RelyX a significant increase in bond strengths was detected for the middle and apical region (P < 0.01; t-test, Bonferroni factor 18). CONCLUSIONS: Bond strengths were affected significantly by luting agent and root position. RelyX had higher bond strengths compared with other materials. The apical region of the canals was characterized by significantly higher bond strengths.

Analysis of Variance↗
PubMed2004

Signs of temporomandibular disorders in tinnitus patients and in a population-based group of volunteers: results of the Study of Health in Pomerania.

The literature has documented a controversial discussion on the possible relationship of otogenous symptoms and craniomandibular dysfunction since the 1920s. Therefore, an investigation was conducted which consisted of two parts: a case study with population-based controls and a cross-sectional study. The aim of the first study was to screen a group of patients suffering from acute or chronic tinnitus for temporomandibular disorders (TMD) in comparison with a population-based group of volunteers without tinnitus. To this end, 30 patients (13 females and 17 males, age 18-71 years) suffering from acute hearing loss associated with tinnitus, isolated acute tinnitus, and chronically transient tinnitus were examined for symptoms of craniomandibular dysfunction. The results were compared with those of clinical functional analysis from 1907 subjects selected representatively and according to age distribution from the epidemiological 'Study of Health in Pomerania' (SHIP); the occurrence of tinnitus was ruled out in these control subjects. Statistical analysis was performed with Chi-square and Mann-Whitney U-tests. Sixty per cent of the tinnitus patients and 36.5% of the control subjects exhibited more than two symptoms of TMD (P = 0.004). Tinnitus patients had significantly more muscle palpation pain (P < 0.001), temporomandibular joint (TMJ) palpation pain (P < 0.001), and pain upon mouth opening (P < 0.001) than the general population group. No statistical differences were found in TMJ sounds, limitation of mandibular movement, or hypermobility of the TMJ. Furthermore, 4228 subjects of the population group examined in the epidemiological study were screened for co-factors of tinnitus with the help of a multivariate logistic regression model which was adjusted for gender, age, and a variety of anamnestic and examined data. Increased odds ratios (OR) were found for tenderness of the masticatory muscles (OR = 1.6 for one to three painful muscles and OR = 2.53 for four or more painful muscles), TMJ tenderness to dorsal cranial compression (OR = 2.99), listlessness (OR = 2.0) and frequent headache (OR = 1.84) A relationship between tinnitus and TMD was established in both examinations. Tinnitus patients seem to suffer especially from myofascial and TMJ pain. A screening for TMD should be included in the diagnostic survey for tinnitus patients.

Acute Disease↗
PubMed2004

A Confocal Laser Scanning Microscope investigation of different dental adhesives bonded to root canal dentine.

AIM: To evaluate the resin-dentine interface of different adhesive systems and corresponding luting cements proposed for bonding fibre posts to root canal dentine. METHODOLOGY: Fifty extracted maxillary canines and central incisors were used. After root canal treatment the teeth were randomly divided into five groups of 10 teeth each. Fibre posts were inserted with five different adhesive systems and corresponding luting cements. Group 1: Clearfil Core/New Bond (Kuraray), group 2: Multilink (Vivadent), group 3: Panavia 21/ED Primer (Kuraray), group 4: PermaFlo DC (Ultradent), and group 5: Variolink II/Excite DSC (Vivadent). The primer was labelled in each case with 0.1% Rhodamine B isothiocyanate (RITC). Each root was sectioned into 2 mm thick slices at 1, 4 and 7 mm below the cementoenamel junction. The resin-dentine interface was evaluated using a Confocal Laser Scanning Microscope; the thickness of the hybrid layer and the number of resin tags were measured. The statistical analysis was performed using nonparametrical tests for comparisons between groups; for overall comparisons the Kruskal-Wallis test was used. Intraindividual analysis within teeth was performed using a linear model. RESULTS: The thickness (microm) of the hybrid layer of group 1 (5.45; SD 1.21), group 4 (3.36; SD 1.59), and group 5 (4.33; SD 1.19) was significantly higher than in the other groups (P < or = 0.05). The number of resin tags observed in group 1 was significantly higher than in groups 2-4 (P < 0.05), but did not differ from group 5. Each group showed significantly more resin tags in the coronal and in the central part of the root canal than in the apical part (P < 0.001). CONCLUSION: Conditioning of the root canal dentine with phosphoric acid and the use of one- and two-bottle-bonding systems gave a thicker and more uniform hybrid layer with considerably more resin tags than observed after the use of 'self-etching' adhesives. This might provide a more durable bond of the post to root canal dentine.

Acid Etching, Dental↗
PubMed2003

Postoperative chemotherapy with cisplatin and 5-fluorouracil in cancer of the oral cavity and the oropharynx--long-term results.

Adjuvant chemotherapy has not yet been proven to have a survival benefit for patients with head and neck cancer. Studies dealing with this topic have had several faults like mingling tumor localizations and treatment modalities. To re-examine the role of postoperative chemotherapy in oral cavity cancer, a single-center study was conducted with the attempt to have higher homogeneity. 122 patients with primary squamous cell carcinoma of the lip, the oral cavity and the oropharynx have been treated with 100 mg/m2 cisplatin bolus infusion and 120-h continuous infusion of 1000 mg/m2 5-fluorouracil following radical surgery; 99 patients completed all 3 cycles. The disease-free and overall survival are reported and compared to a control group of 161 patients with cancer of the lip, the oral cavity and oropharynx treated only with surgery, and a treatment-dependent prognostic index. After a median follow-up of 79 months (range 5-18 years), the current 5-year overall survival of the chemotherapy group was 67% and the 5-year disease-free survival was 57% while the respective data for the control group are 46% and 40%. This difference is statistically significant. The comparison with the prognostic index confirmed this result. The chemotherapy group suffered from fewer local and more neck relapses and had a much longer relapse latency (29 months versus 8 months). The toxicity of the chemotherapy regimen was tolerable. In a homogeneous population with resectable oral cavity and oropharyngeal cancer, postoperative adjuvant chemotherapy with cisplatin and 5-fluorouracil resulted in a high overall survival rate which was significantly better than in a comparable population treated only with surgery and better than the survival expectation calculated with the help of a prognostic index. A prospective randomized study of postoperative chemotherapy versus control, exclusively in patients with oral cancer, is warranted.

Adult↗
PubMed2001

Repair of bilateral cleft lip, alveolus and palate Part 3: Follow-up criteria and late results.

The last part of this series outlines closure of the hard palate with various modifications depending on the remaining width of the cleft. Additionally the necessity and parameters of follow-up documentation are emphasized and detailed. For the two patients shown in Parts 1 and 2, the corresponding data are given. Accumulated facial growth curves of all the other patients treated the same way are also given. The main results are: (A) lip and nose can be reconstructed much more easily after repositioning of the premaxilla and (B) the reported anterior growth delay following use of the Latham appliance could not be confirmed during the ongoing follow-up. Copyright 2001 European Association for Cranio-Maxillofacial Surgery.

Journal Article↗
PubMed2001

Repair of bilateral clefts of lip, alveolus and palate Part 2: Concomitant lip closure and columella lengthening after lip adhesion.

Lip repair and synchronous columella lengthening in bilateral clefts of the lip, alveolus and palate following lip adhesion according to the method outlined in Part 1 is described in this part of the paper. Together with lip and nose repair the gingivo-periosteoplasty can also be performed when the alveolar process is perfectly aligned and the greater and lesser segments abutt onto each other. Copyright 2001 European Association for Cranio-Maxillofacial Surgery.

Journal Article↗
PubMed2001

Repair of bilateral clefts of lip, alveolus and palate Part 1: A refined method for the lip-adhesion in bilateral cleft lip and palate patients.

The protruding premaxilla represents the most severe problem in the surgical closure of a bilateral cleft lip, alveolus and palate (BCLP). In principle there are two methods to overcome this obstacle: (1) preliminary lip adhesion and (2) presurgical repositioning with intraoral devices. According to the various degrees of premaxillary protrusion, sometimes adhesion alone is sufficient, if the surgical technique is unlikely to break down. In this paper a refined adhesion method is presented, withstanding traction to the wound margins and concomitantly enables lip and nose repairs in a single second operation. For patients with severe premaxillary protrusion, presurgical use of a Latham appliance achieves conditions for safe lip adhesion as above. Both treatment methods are outlined. Copyright 2001 European Association for Cranio-Maxillofacial Surgery.

Journal Article↗
PubMed2000

[Primary surgical treatment of lip-jaw-palate clefts in the year 2000. Report of the development of methods in the last 30 years and current status of surgical technique].

In this paper an attempt is made to survey the surgical treatment of cleft lip and palate regarding all classifications and all parts of the cleft. The most important developments up to 30 years ago to have been summarized in Millard's three-volume "Cleft Craft". Therefore, the author tries to analyze the present state-of-the-art cleft surgery. This part is certainly of a subjective nature due to the high rate of complexity in cleft malformations.

Child↗
PubMed1998

Prospective comparison of 18F-FDG PET with conventional imaging modalities (CT, MRI, US) in lymph node staging of head and neck cancer.

The aims of this study were to investigate the detection of cervical lymph node metastases of head and neck cancer by positron emission tomographic (PET) imaging with fluorine-18 fluorodeoxyglucose (FDG) and to perform a prospective comparison with computed tomography (CT), magnetic resonance imaging (MRI), sonographic and histopathological findings. Sixty patients with histologically proven squamous cell carcinoma were studied by PET imaging before surgery. Preoperative endoscopy (including biopsy), CT, MRI and sonography of the cervical region were performed in all patients within 2 weeks preceding 18F-FDG whole-body PET. FDG PET images were analysed visually and quantitatively for objective assessment of regional tracer uptake. Histopathology of the resected neck specimens revealed a total of 1284 lymph nodes, 117 of which showed metastatic involvement. Based on histopathological findings, FDG PET correctly identified lymph node metastases with a sensitivity of 90% and a specificity of 94% (P<10(-6)). CT and MRI visualized histologically proven lymph node metastases with a sensitivity of 82% (specificity 85%) and 80% (specificity 79%), respectively (P<10(-6)). Sonography revealed a sensitivity of 72% (P<10(-6)). The comparison of 18F-FDG PET with conventional imaging modalities demonstrated statistically significant correlations (PET vs CT, P = 0.017; PET vs MRI, P = 0.012; PET vs sonography, P = 0.0001). Quantitative analysis of FDG uptake in lymph node metastases using body weight-based standardized uptake values (SUVBW) showed no significant correlation between FDG uptake (3.7+/-2.0) and histological grading of tumour-involved lymph nodes (P = 0.9). Interestingly, benign lymph nodes had increased FDG uptake as a result of inflammatory reactions (SUVBW-range: 2-15.8). This prospective, histopathologically controlled study confirms FDG PET as the procedure with the highest sensitivity and specificity for detecting lymph node metastases of head and neck cancer and has become a routine method in our University Medical Center. Furthermore, the optimal diagnostic modality may be a fusion image showing the increased metabolism of the tumour and the anatomical localization.

Carcinoma, Squamous Cell↗
PubMed1992

Latham's appliance for presurgical repositioning of the protruded premaxilla in bilateral cleft lip and palate.

Dislocation of the maxillary segments in cleft lip and palate still is a challenge to the surgeon and the orthodontist. The premaxillary protrusion in bilateral cleft lip and palate, complicates the treatment severely. Latham's appliance, inserted on average at 2-months-of-age, relocates the segments over 3-4 weeks. Removal of the appliance is immediately followed by functional surgery. The first operation comprises: (1) intra-alveolar veloplasty; (2) closure of the alveolar cleft with the help of a gingivo-periosteal-plasty; (3) lip adhesion and (4) insertion of ear tubes. This operating schedule establishes the functional matrix as early as possible. Midfacial growth as well as language and speech development are provided with the necessary preconditions as far as we understand this complex situation. Five cases, being representative of 41 cases, are outlined in detail. The longest follow up period is 3 years; no growth disturbance of the maxilla has been detected to date. Definitive lip and columella surgery is facilitated.

Child, Preschool↗
PubMed1991

Experiences in surgical repair of a totally avulsed scalp.

A case of total scalp avulsion is described in surgical detail. The neurovascular bundles remained nearly untouched on the surface of the galea aponeurotica. Only one frontal branch of the left temporal artery was found to serve as a nutrient vessel for the whole scalp. Three veins around the scalp circumference supplied the venous drainage. The right-dorsal part of the scalp underwent necrosis, obviously because of internal disruption on the capillary level. This area had to be skin-grafted secondarily. Mechanical aspects in respect of the neuro-vascular situation are discussed theoretically and some advice on the surgical approach is derived from our experience.

Adolescent↗
PubMed1988

Refined intraoperative repositioning of the osteotomized maxilla in relation to the skull and TMJ.

In dysgnathic patients, who have to be treated by surgical repositioning of the jaws, the necessary bone movements are predicted preoperatively with the help of sophisticated analysis. A high degree of accuracy, could not however be transferred to the patient, because of lack of an operative procedure as accurate as the preplanning. In this paper a face-bow is described, provided with an interocclusal splint that has been adjusted beforehand on an articulator, in a model operation taking into account the skull and TMJ relationship. Using this face-bow-splint combination the possibility of greater accuracy in transferring the preplanned movements to the patient is facilitated. The computerized preplanning, the model operation and the technical procedure as well as the operation itself are described, step by step.

Cephalometry↗