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Biomedical subjects

Ann Wenzel

Publications and source records attributed to Ann Wenzel.

At least 19 recordsLinked to original sources
PubMed2007

Influence of cyclosporin A on quality of bone around integrated dental implants: a radiographic study in rabbits.

OBJECTIVES: To evaluate the influence of cyclosporin A (CsA) administration on bone around integrated dental implants assessed by a bone quality index and by quantitative subtraction radiography. MATERIAL AND METHODS: A total of 36 machine surface commercial implants were placed in 18 adult rabbits. After a 3-month healing period without any disturbance, the animals were randomly divided into three groups of six animals each. Group A was sacrificed at this time. CsA was injected subcutaneously in an immunosuppressive dose of 10 mg/kg/day in a test group (Group T), and a Group B served as a control, receiving only vehicle. After 3 months of cyclosporin administration, the animals of both Groups B and T were sacrificed. Radiographs were obtained at implant surgery and at the day of sacrifice with a CMOS sensor. Bone quality around the implants was compared between the groups using a bone quality index and quantitative subtraction radiography. RESULTS: The bone analysis showed that in Group T, the bone quality changed dramatically from a dense cortical to a loose trabecular bone structure (P<0.0001, chi(2) test) while in Groups A and B there were no significant differences. Quantitative digital subtraction radiography showed significantly (P<0.05) lower gray shade values (radiographic density) in a region of bone formation around the implants in Group T (118+/-12) than in Groups A (161+/-6) and B (186+/-10). CONCLUSION: Within the limits of this study, CsA administration has a negative effect on the quality of bone around integrated dental implant.

Animals↗
PubMed2006

Accuracy of cone beam dental CT, intraoral digital and conventional film radiography for the detection of periapical lesions. An ex vivo study in pig jaws.

To compare the accuracy of cone beam CT scanning (NewTom 3G) with intraoral periapical radiography (Dixi2, Planmeca CCD sensor and Insight film) for the detection of periapical bone defects. Ten frozen pig mandibles were used. All soft tissues were removed and the jaws were sagittally sectioned to obtain three blocks from each side of the jaw containing the premolars and the molars with surrounding jaw bone. All teeth with intact roots were then "extracted". First, 15 blocks were used to define defect size and exposure parameters; then, the remaining 45 blocks were divided into three equal groups. In one group, cylindrical defects of 1 x 1 mm were prepared beyond the apices of the extraction sockets, in another group defects of 2 x 2 mm were similarly prepared, while no defects were prepared in the last group. The teeth were replaced into their sockets and digital and conventional radiographs of all blocks were taken under reproducible conditions. In addition, all blocks were CT scanned with the same volumetric data and then reconstructed to provide sagittal and coronal 2-D sections. Masked evaluation of the images (defect present vs no defect) was performed by four calibrated examiners. Statistical analysis was performed with ANOVA and the significance level was set to P < 0.05. NewTom 3G was statistically significantly better in terms of sensitivity (54%), positive (82.6%) and negative (44.5%) predictive values, and diagnostic accuracy (61%) when compared with digital radiographs (23%, 60%, 31%, 39%), and with conventional ones (28%, 70%, 35%, 44%)-except in the positive predictive value. Specificity was similar for all three methods. No difference was observed between the two periapical (digital vs conventional) radiographs. NewTom 3G may be useful in cases of immediate implants intended to replace teeth with suspicion for possible existing endodontic pathology, or in candidate implant sites neighboring such teeth.

Alveolar Bone Loss↗
PubMed2006

Marginal bone level in an adult Danish Population.

PURPOSE: To investigate the prevalence and distribution of marginal bone loss in the Danish population. MATERIALS AND METHODS: Six hundred and sixteen randomly selected Danish adults (304 females and 312 males), mean age of 42 years (range 21-63 years) underwent a full-mouth radiographic survey consisting of 14 periapicals and two bitewings. The marginal bone level was measured with a digital caliper in mm, rounded off to the nearest 0.1 mm. The measurements were performed at the mesial and distal aspect of the tooth, from the cemento-enamel junction to the marginal bone. These measurements were used to calculate the marginal bone level (A) in mm for each tooth and each patient. Three thresholds were defined: normal marginal bone level (A < 3 mm), borderline marginal bone level (3 mm < or = A < 4 mm) and reduced marginal bone level (A > or = 4 mm). RESULTS: The prevalence of reduced marginal bone level in the individual and the frequency of teeth with reduced marginal bone level were almost similar. A reduced marginal bone level was evenly distributed among the tooth groups. Approximately 12% had reduced marginal bone level, 12% were in the borderline marginal bone level group, and the remaining 76% had a normal marginal bone level. The marginal bone level was ever more reduced with increasing age. No significant difference in bone level was observed between genders. CONCLUSIONS: The prevalence of reduced marginal bone level in a random Danish population is approximately 12% and is comparable to findings in other European countries.

Adult↗
PubMed2006

Risk indicators for a reduced marginal bone level in the individual.

PURPOSE: The aim of this study was to assess risk indicators for reduced marginal bone level in the individual, with emphasis on apical periodontitis. MATERIALS AND METHODS: Six hundred and sixteen randomly selected Danish adults (304 women and 312 men), mean age of 42 years, underwent a full-mouth radiographic survey. The marginal bone level was measured from the cemento-enamel junction to the marginal bone. The measurements were performed at the mesial (Am) and distal (Ad) aspect of the tooth. The marginal bone level for each individual was calculated: Aind = sigma Ateeth/nteeth, and Aind > or =4 mm was considered as reduced marginal bone level. The periapical status was assessed by the periapical index (PAI), which was dichotomised (healthy = PAI scores 1 and 2, and diseased = PAI scores 3, 4 and 5). Coronal restorations (crowns, fillings and inlays) and smoking status were also recorded. All variables were analysed in a logistic regression model with reduced marginal bone level as the outcome. RESULTS: The impact of age (odds ratio (OR) = 3.3), smoking (OR = 10.5) and apical periodontitis (OR = 4.7) on reduced marginal bone level was statistically significant (p < 0.01). CONCLUSIONS: Not surprisingly, this study showed that smoking and older age were risk indicators for having reduced marginal bone level > or =4 mm. Even when adjusted for these factors, individuals with > or =1 tooth with apical periodontitis were five times more at risk of having a reduced marginal bone level than those with no periapical infection.

Adult↗
PubMed2005

Clinical and radiographic performance of delayed-immediate single-tooth implant placement associated with peri-implant bone defects. A 2-year prospective, controlled, randomized follow-up report.

OBJECTIVES: The aim of the present study was to compare the delayed-immediate (Im) and the delayed (De) protocols for placement of single-tooth implants. MATERIAL AND METHODS: After allocation to the Im and De groups by random, 46 patients were treated with a single-tooth implant with acid etched surfaces (Osseotite) in the anterior or pre-molar region of the maxilla or the mandible on average 10 days (Im) or 3 months (De) following tooth extraction, respectively. Forty-one patients attended a follow-up visit 2 years after implant placement corresponding to 1(1/2) years of loading of the implant restorations. Peri-implant and prosthetic parameters were evaluated clinically and marginal bone levels measured on radiographs. RESULTS: Three implants were lost, all before mounting of the crown. None of the implant restorations had failed after 1(1/2) years of function. Probing pocket depths were reduced by up to 1.4 mm on average from the time of loading to the 2-year follow-up and at that time, no significant difference between the Im and De groups was found (4.2 versus 4.1 mm). A statistically significant radiographic marginal bone loss had occurred in the Im group (mean=0.8 mm) as well as in the De group (mean=0.7 mm) in the follow-up period. However, a mean marginal bone level of approx. 1.5 mm in both groups measured from the implant-abutment junction was found to be acceptable. It was demonstrated that probing pocket depths and marginal bone levels after 1(1/2) years of loading of the implant-retained crowns were not influenced by the presence of peri-implant bone defects immediately after implant placement. Furthermore, no severe prosthodontic complications, such as screw loosening or porcelain fractures, arose in this study material. CONCLUSION: High success rates of single-tooth implants after 1(1/2) years of function were achieved using the delayed-immediate and delayed implant placement techniques.

Alveolar Bone Loss↗
PubMed2005

High resolution charge-coupled device sensor vs. medium resolution photostimulable phosphor plate digital receptors for detection of root fractures in vitro.

The aim of this study was to compare the diagnostic accuracy of a high resolution charge-coupled device (CCD) sensor and a medium resolution photostimulable phosphor (PSP) plate for detecting experimentally induced root fractures and further, to evaluate differences between images taken with various horizontal and vertical angles. Forty-seven extracted single-rooted human teeth mounted in a dry human skull were used in the experiment. The teeth were radiographed, before and after root fractures were induced, with two digital receptors: the Digora PSP system (approx. 8 lp mm(-1)) and the RVG-ui(TM), a CCD sensor with a high-resolution mode (15-20 lp mm(-1)). Four images were taken with each of the receptors of each tooth: one orthogonal exposure (O-images), one exposure with a vertical angle of 15 degrees by which the root was imaged elongated (L-images), and two eccentric exposures with a horizontal angle of 15 degrees mesially and distally. Three observers marked a fracture line if detected, in each image. Three sessions were held, one assessing the O-images, one the L-images, and one in which all four images of the same tooth were displayed simultaneously (X-images). The RVG-ui images obtained higher sensitivities than the Digora PSP images (P <0.05). Sensitivity was statistically significantly higher for the X-images than for both the O-images and the L-images (P <0.05). Based on the observed means, specificities were significantly different neither between the angles, nor between the images from the two digital systems taken with the same angle (P >0.05). It may be speculated that the difference in spatial resolution between the two digital systems accounts for the differences in their sensitivity.

Analysis of Variance↗
PubMed2004

Mandibular third molar removal: risk indicators for extended operation time, postoperative pain, and complications.

OBJECTIVES: The aim of this study was to identify risk indicators for extended operation time and postoperative complications after removal of mandibular third molars. STUDY DESIGN: There were 388 molars included in the study. The teeth were removed using the buccal approach under local anesthesia. Four hours postoperatively the patient recorded his or her pain perception on a visual analogue scale (VAS). After surgery a surgeon recorded parameters regarding the tooth and if the mandibular nerve had been visible during the operation. One week postoperatively the postoperative pain and complications were recorded. Logistic regression models were made to identify risk indicators for extended operation time, postoperative pain, and complications. RESULTS: Females were at higher risk for postoperative pain and dry socket than males. Older patients were at higher risk for extended operation time than younger patients. Radiographically fully impacted molars increased the risk of postoperative general infection. If the nerve was visible during surgery there was a higher risk of a high VAS score, postoperative pain, and general infection than if the nerve had not been visible. CONCLUSION: Several indicators were found to increase the risk of postoperative complications, but a visible alveolar inferior nerve during the operation was repeatedly found to be the highest single risk indicator.

Adolescent↗
PubMed2004

Accuracy of digital panoramic images displayed on monitor, glossy paper, and film for assessment of mandibular third molars.

OBJECTIVE: The aim of this study was to compare the accuracy of 3 modalities of digital panoramic radiographs-monitor-displayed images and printed copies on glossy paper and on blue transparent film-for assessment of position and morphology of mandibular third molars. STUDY DESIGN: 164 third molars were recorded with one of 2 digital panoramic systems (Digora and Orthophos Plus) and assessed by 4 observers on 3 radiographic modalities: monitor display, glossy paper, and transparent film. The assessments were compared with surgeons' findings at the time of the operation ("gold standard"). RESULTS: Overall, the observer variation was larger than the variation between methods. A detailed paired analysis revealed some differences between the modalities for some diagnostic categories, but these were few and inconsistent. CONCLUSION: Printed images from the Kodak 1200 ink-jet printer on glossy paper and blue transparent film may be as accurate as the original monitor-displayed digital panoramic images from the Digora and Orthophos Plus systems for assessment of position and morphology of mandibular third molars.

Adolescent↗
PubMed2004

Tooth-specific risk indicators for apical periodontitis.

The present study aimed at identifying tooth-specific risk indicators for apical periodontitis (AP) and to investigate their interrelations in order to identify those teeth that would benefit from a radiographic examination. The study included 311 males and 302 females who gave written informed consent and attended a full-mouth radiographic examination. All teeth were assessed individually. AP was scored by the periapical index (PAI); other variables were root fillings, coronal fillings and crowns, pulpal posts, and caries. A conditional logistic regression analysis was used to assess the effect of tooth-specific risk indicators on the presence of apical periodontitis. The dependent variable was presence of AP versus absence of AP in the tooth. A total of 536 teeth with AP were identified. A highly increased risk for AP was seen in teeth with root fillings, particularly for technically inadequate ones. Presence of coronal fillings also increased the risk for AP, and inadequate fillings were associated with a slightly higher risk than adequate fillings. A similar pattern was seen for crowns. Teeth with caries also had an increased risk of AP, but the difference was only statistically significant for primary caries. Compared to first incisors, second incisors and canines had a significantly reduced risk, and molars, especially first maxillary molars, had a significantly increased risk for having AP.

Adult↗
PubMed2004

Patient experience of, and satisfaction with, delayed-immediate vs. delayed single-tooth implant placement.

OBJECTIVES: Recent investigations have focused on patients' subjective assessment of implant treatment. The aim of this study was to compare the patients' experience of surgical and prosthetic procedures, as well as satisfaction with function and aesthetics following single-tooth replacements mounted to early vs. delayed placed dental implants. MATERIAL AND METHODS: Forty-six patients were treated with a single-tooth implant in the anterior or premolar region. Twenty-three implants were placed on average 10 days after tooth extraction (Im), while 23 implants were placed approximately 3 months after tooth extraction (De). Forty-one patients completed a questionnaire regarding the treatment using visual analog scales (VAS) and check boxes 16-18 months after delivery of the restoration. RESULTS: In all, 90% of the respondents rated 88 or higher on the VAS regarding satisfaction with the crown. Satisfaction with the restoration in general and the appearance was significantly greater in the Im group than in the De group (96 vs. 93; P<0.02). Assessment of the implant surgery was not significantly different between the delayed-immediate and the delayed group. Approximately 25% of the patients experienced unpleasantness in relation to the prosthetic procedures, and in 8 of 11 cases, impression taking was the cause. When evaluating satisfaction with the overall implant treatment, the VAS scores for the delayed-immediate group were significantly higher than for the delayed group (96 vs. 90; P<0.02). CONCLUSION: The patients in the present study were highly satisfied with the outcome of the treatment and experienced it to be without significant unpleasantness irrespective of the treatment concept.

Adult↗
PubMed2003

Comparison of the effect of video glasses and nitrous oxide analgesia on the perceived intensity of pain and unpleasantness evoked by dental scaling.

The aim of this study was to evaluate whether distraction induced by video glasses had an effect on the perceived intensity of pain and unpleasantness during dental scaling compared with the effect of nitrous oxide (N(2)O) analgesia. The pain stimulus was dental scaling (removal of dental calculus) with an ultrasonic scaler. As a standardised, non-dental painful stimulus, Von Frey filaments were used. A total of 26 patients with superficial chronic periodontitis were enrolled in this randomised, controlled clinical study. The effect of video glasses was compared with N(2)O in one session and the effect of video glasses versus a control situation in another. The patients rated the intensity of pain and unpleasantness evoked by dental scaling and Von Frey filament stimulation on 100-mm visual analogue scales (VAS). For dental scaling, there was no effect of video glasses on the perceived pain (p=0.85) or unpleasantness (p=0.73) nor of N(2)O (p=0.69 and p=0.51, respectively) compared with the control situation. Similarly, no significant difference was found between VAS scores in the video glasses and N(2)O session (p=0.48, p=0.58). A significant effect of video glasses and N(2)O(p<0.008) was found on the perceived pain intensity produced by Von Frey filament stimulation compared with the control situation, but no significant difference was seen between these methods (p=0.07). Post-treatment interviews of the patients revealed that 81% of the patients in the video and 65% in the N(2)O session stated that the method had some beneficial effect on their overall experience of the treatment situation. In conclusion, administration of video glasses or N(2)O did not affect the perceived intensity of pain and unpleasantness evoked by dental scaling.

Adult↗
PubMed2003

Anorganic porous bovine-derived bone mineral (Bio-Oss) and ePTFE membrane in the treatment of peri-implantitis in cynomolgus monkeys.

The purpose of the present study was to evaluate the effect of anorganic porous bovine-derived bone mineral (Bio-Oss) and expanded polytetrafluoroethylene (ePTFE) membrane in the treatment of peri-implantitis. A total of 64 implants with a titanium plasma-sprayed (TPS) surface was inserted in eight cynomolgus monkeys (Macaca fascicularis). After a 3-month healing period with plaque control, experimental peri-implantitis characterized by a bone loss of 4-6 mm was induced during a period of 9-18 months. Surgical treatment involving Bio-Oss+membrane, Bio-Oss, membrane, or a conventional flap procedure (control) only was carried out. The animals were sacrificed six months after treatment. Evaluation by clinical parameters, radiography including quantitative digital subtraction radiography, histology, and stereology demonstrated healthy peri-implant tissue irrespective of the applied surgical procedure. However, the amount of re-osseointegration and the total amount of bone (Bio-Oss and regenerated bone) were significantly higher in defects treated with membrane-covered Bio-Oss as compared with the other three treatment procedures. A mean bone-to-implant contact of 36% was obtained within defects treated with membrane-covered Bio-Oss. The corresponding values for the three other treatment procedures were 13-23%. The Bio-Oss particles were in general highly integrated within the regenerated bone, but the particles in the occlusal part of the defects were entirely surrounded by connective tissue irrespective of membrane coverage. The present study demonstrates that surgical treatment involving Bio-Oss covered by an ePTFE membrane is a useful treatment modality of experimental peri-implantitis around implants with a TPS surface in cynomolgus monkeys. However, the treatment outcome is not as encouraging as seen with membrane-covered autogenous bone graft particles documented in a study with same experimental design.

Alveolar Bone Loss↗
PubMed2003

Implant surface preparation in the surgical treatment of experimental peri-implantitis with autogenous bone graft and ePTFE membrane in cynomolgus monkeys.

The aim of the present investigation was to assess the effect of four implant surface preparation methods used in the surgical treatment of experimental peri-implantitis with autogenous bone graft and expanded polytetrafluoroethylene (ePTFE) membrane. The methods were air-powder abrasive unit+citric acid, air-powder abrasive unit, gauze soaked in saline+citric acid, and gauze soaked alternately in chlorhexidine and saline. A total of 64 implants with a titanium plasma-sprayed (TPS) surface was placed in eight cynomolgus monkeys (Macaca fascicularis). After a 3-month period with plaque control, experimental peri-implantitis was induced. A bone loss of 4-6 mm was established after 9-17 months and plaque control was re-implemented. The peri-implantitis defects were surgically exposed, granulation tissue was removed, and each implant surface was prepared by one of the above-mentioned procedures. The defects were then filled with autogenous bone graft particles and covered by an ePTFE membrane. The animals were sacrificed after 6 months. Evaluation by clinical parameters, radiography including quantitative digital subtraction radiography, histology, and stereology did not reveal significant differences between the methods. Almost total bone regeneration and considerable re-osseointegration were obtained irrespective of the method applied. A mean bone-to-implant contact of 39-46% was observed within the defects. Therefore, the present study of implants with a TPS surface in cynomolgus monkeys indicates that the simplest method involving gauze soaked alternately in chlorhexidine and saline should be the preferred implant surface preparation method in the surgical treatment of peri-implantitis involving autogenous bone graft and ePTFE membrane.

Alveolar Bone Loss↗
PubMed2003

Autogenous bone graft and ePTFE membrane in the treatment of peri-implantitis. I. Clinical and radiographic observations in cynomolgus monkeys.

The purpose of the study was to examine the effect of autogenous bone graft particles and expanded polytetrafluoroethylene (ePTFE) membrane in the treatment of peri-implantitis. The treatment outcome was evaluated by clinical and radiographic methods including quantitative digital subtraction radiography. A total of 64 implants with a titanium plasma-sprayed (TPS) surface was inserted in eight cynomolgus monkeys (Macaca fascicularis). After a 3-month healing period with plaque control, experimental peri-implantitis characterized by a bone loss of 4-6 mm was established during 14-22 months. Plaque control was then re-implemented and surgical treatment involving autogenous bone+membrane (B+M), autogenous bone (B), membrane (M), or a conventional flap procedure alone (control) (C) was performed. The animals were killed 6 months after treatment. Healthy peri-implant tissue was established irrespective of the applied surgical procedure. A mean bone gain of 4.7 mm was identified around implants treated with B+M, while, respectively, 4.0, 3.0, and 1.9 mm were recorded within the B, M, and C groups. Quantitative digital subtraction radiography confirmed considerable bone gain within defects treated with autogenous bone with or without membrane coverage. The bone gain, especially for defects treated with B+M, seemed to be almost to the level before development of peri-implantitis. By contrast, 38 and 25% of the defect was on average characterized by bone gain when, respectively, M or C was used alone. The present study of implants with a TPS surface in cynomolgus monkeys thus demonstrates considerable bone regeneration after treatment of experimental peri-implantitis with autogenous bone graft particles with or without ePTFE membrane coverage. Further stereologic and histologic evaluation of the treatment outcome is necessary before final conclusions about the effect of autogenous bone graft and ePTFE membrane can be made.

Animals↗
PubMed2003

Risk indicators for apical periodontitis.

OBJECTIVES: The aim of the study was to identify risk indicators for apical periodontitis (AP) in the individual. A parameter was defined as a 'risk indicator' when its presence increased the individual's risk of exhibiting AP. Risk indicators may, but need not be directly associated with the disease. METHODS: The study included full-mouth surveys of 613 randomly selected individuals, who were 20-60 years old and living in Aarhus County. Logistic regression analyses were performed. The outcome variable was >or=1 AP/no AP. The independent variables were obtained from information on socioeconomic and dental status. RESULTS: It was found that smoking, no usage of services from the dentist, >or=2 secondary caries lesions, >or=3 inadequate coronal fillings and the presence of root filling(s) were statistically associated with AP. A separate analysis for individuals with no previous root fillings showed that individuals with regular dental visits as well as individuals who had all their teeth (third three molars excluded) were less likely to have AP, whereas individuals who had >or=3 inadequate coronal fillings were more likely to have AP. CONCLUSIONS: The results from the present study of a Danish population showed that the most important risk indicator of having AP in the individual was the radiographic evidence of root fillings. The presence of several caries lesions, the quality of the dental treatment, the regularity of dental visits and smoking were also statistically associated with AP. Further, the socioeconomic status of the individual did not provide much additional information on the periapical status.

Adult↗
PubMed2003

Bone healing and soft tissue contour changes following single-tooth extraction: a clinical and radiographic 12-month prospective study.

Preservation of alveolar bone volume following tooth extraction facilitates subsequent placement of dental implants and leads to an improved esthetic and functional prosthodontic result. The aim of the present study was to assess bone formation in the alveolus and the contour changes of the alveolar process following tooth extraction. The tissue changes after removal of a premolar or molar in 46 patients were evaluated in a 12-month period by means of measurements on study casts, linear radiographic analyses, and subtraction radiography. The results demonstrated that major changes of an extraction site occurred during 1 year after tooth extraction.

Adult↗
PubMed2002

Accuracy of computer-automated caries detection in digital radiographs compared with human observers.

The aim of this study was to compare diagnostic accuracy of a caries detection program with that of human observers. A total of 190 extracted teeth were radiographed with two Trophy RVG (RadioVisioGraphy) digital sensor systems. Four observers scored the approximal surfaces in all images on a disease severity scale. Each observer thereafter used the Logicon Caries Detector (LCD) program to analyse the surfaces in the digital images and recorded their outcome. To determine the true absence or presence of caries, histological validation was used. Sensitivities, specificities, positive and negative predictive values were calculated and differences between the diagnostic methods tested. Specificities for the outcome with the LCD were significantly lower for three observers than when they themselves assessed the RVG images and, correspondingly, the positive predictive values were lower for the LCD outcome for three of the observers. Sensitivity was also lower for two observers on the diagnostic threshold caries in dentine. It was concluded that the automated caries detection program is less accurate than human observers in detecting approximal caries lesions.

Bicuspid↗