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Implant failure has been associated with factors such as poor bone quality, insufficient bone volume, implant instability, unfavorable implant loading, and smoking habits. Infections and host responses may also be important factors in dental implant failure. The objectives of the present study were to identify various explanatory factors associated with titanium implant failure. Forty subjects with stage 1 non-osseointegrated titanium dental implants (NOTI) ad modum Brånemark and 40 age- and gender matched control subjects with successfully osseointegrated titanium implants (SOTI) were studied. Clinical data and gamma G immunoglobulin (IgG) antibody titers were studied. An independent t test revealed that significantly longer implants were placed in subjects with SOTI (P < .05). Statistically significant differences in bone shape and resorption (BSR) scores were found between SOTI and NOTI (P < .05). Logistic regression analysis identified 3 significant explanatory outcome variables: serum antibody avidity scores for Bacteroides forsythus (P < .0001), serum antibody titers to Staphylococcus aureus (P < .001), and the BSR scores (P < .05). Antibody avidity to B forsythus and antibody titer to S aureus were therefore the 2 most important factors associated with early implant failures and with a significant predictive ability. This indicates that immunologic factors are involved in osseointegration. [ABSTRACT FROM AUTHOR]

This study examined whether it is possible to restore an edentulous mandible with a complete-arch fixed prosthesis retained by only 4 implants without decreasing the survival rate. One hundred nineteen patients received complete-arch mandibular prostheses retained by 4 implants. Most patients were followed for 3 years or more. All patients followed a routine protocol, including annual check-ups and regular radiographic examinations. Twenty-one patients dropped out. Radiographic measurements used the threads of the implants as a basis for comparison. No indication was found that the number of supporting implants could have influenced the observed frequency of technical and surgical complications. Three implants were lost, 2 after 1 year and 1 after 5 years. A statistically significant difference in bone loss between the mesial and distal implants was found. The number of fractured resin teeth in mandibular prostheses was higher when patients had an implant-supported prosthesis in the maxilla. The present study revealed an implant survival rate of 98.6% after 5 years. Therefore, it was concluded that there may not be a need for more than 4 implants to support a fixed mandibular prosthesis, when implants at least 10 mm long can be used. [ABSTRACT FROM AUTHOR]

Objective: The present study aims to gain knowledge about the dentist's use and choice of digital extraoral imaging methods, panoramic radiography and cone beam computed tomography (CBCT).Materials and Methods: A questionnaire sent to 2481 dentists within the Swedish Dental Society contained questions about the panoramic technique and CBCT technique used, education, clinic size and type of service. The response rate was 53%.Results: The study showed that 61% of the Swedish dentists had access to panoramic techniques and that 84% used a direct digital sensor, while 6% used storage phosphor plate techniques. Around 8% of the Swedish dentists had access to CBCT. It was also observed that group practices had two times higher odds of having panoramic equipment compared with solo practices. Approximately 40% of the dentists had undergone postgraduate education in oral radiology during the last 5 years. Dental nurses and dental hygienists exposed 92% of the panoramic radiographs and 75% of the CBCTs. Thirty per cent of those clinics with access to a panoramic unit exposed >30 panoramic radiographs per month and 56% of the clinics having access to CBCT did more than 75 examinations per year.Conclusions: Today 61% of Swedish dentists have access to panoramic radiography and 8% have access to CBCT. There is a greater likelihood of having access if the dentist works in the public dental health service or in a group practice and if the dentist has undergone any postgraduate course in oral radiology. [ABSTRACT FROM AUTHOR]

The issue of changes in marginal bone levels around maxillary implants supporting overdentures has been studied very little because of radiographic difficulties when using conventional intraoral techniques. The present study used detailed narrow-beam radiography, which offers excellent opportunities to depict implants and the surrounding bone in severely resorbed maxillae. Marginal bone levels around implants in patients with overdentures were compared to corresponding bone levels in a group of matched control patients with fixed prostheses supported by osseointegrated implants. No statistically significant difference in marginal bone height was noted between the groups. This finding is not in accordance with an earlier report on continuous loss of marginal bone around many maxillary implants supporting overdentures. [ABSTRACT FROM AUTHOR]

Objective The purpose of the present study was to investigate the potential of using advanced external adaptive image processing for maintaining image quality while reducing exposure in dental panoramic storage phosphor plate (SPP) radiography. Materials and methods Thirty-seven SPP radiographs of a skull phantom were acquired using a Scanora panoramic X-ray machine with various tube load, tube voltage, SPP sensitivity and filtration settings. The radiographs were processed using General Operator Processor (GOP) technology. Fifteen dentists, all within the dental radiology field, compared the structural image quality of each radiograph with a reference image on a 5-point rating scale in a visual grading characteristics (VGC) study. The reference image was acquired with the acquisition parameters commonly used in daily operation (70 kVp, 150 mAs and sensitivity class 200) and processed using the standard process parameters supplied by the modality vendor. Results All GOP-processed images with similar (or higher) dose as the reference image resulted in higher image quality than the reference. All GOP-processed images with similar image quality as the reference image were acquired at a lower dose than the reference. This indicates that the external image processing improved the image quality compared with the standard processing. Regarding acquisition parameters, no strong dependency of the image quality on the radiation quality was seen and the image quality was mainly affected by the dose. Conclusions The present study indicates that advanced external adaptive image processing may be beneficial in panoramic radiography for increasing the image quality of SPP radiographs or for reducing the exposure while maintaining image quality. [ABSTRACT FROM AUTHOR]

The objectives were to study the progression rate of approximal caries in 14 to 19-year-old adolescents and to assess the influence of experience of previous caries as a predictor of caries progression during the following years. The study population comprised 100 adolescents, all 19 years old, randomly selected. In all, there were 93 adolescents included in the study, for whom all sets of bitewing radiographs from 14 up to and including the age of 19 were assessed with respect to approximal caries. It could be noted that 32% of the adolescents had had at least one bitewing examination every year from 14 to 19 years of age. At the age of 14, 38% of the males and 24% of the females were radiographically without any sign of caries lesions (caries-free). The median survival time of initial caries in the present study was >5 years, while for manifest caries it was 3.2 years. It was found that 37% of the surfaces with manifest caries in males and 18% of the corresponding surfaces in females were restored within a year. The results show that experience of previous caries does not seem to be a significant indicator and does not influence when the next radiographic examination should be performed. It is thus concluded that individualized bitewing examination is the exception rather than the rule. [ABSTRACT FROM AUTHOR]

Objective: The present study aims to gain knowledge about the dentist's use and choice of digital intraoral imaging methods., Materials and Methods: A questionnaire sent to 2481 dentists within the Swedish Dental Society contained questions about the type of X-ray technique used, problems experienced with digital radiography, and reasons for choosing digital technology, and about indications, clinic size and type of service. Response rate was 53%., Results: Ninety-eight percent of the dentists had made the transition to digital radiography; only 2% used film technique, and solid-state detector (SSD) was the most used digital technique. More years in service decreases the likelihood of applying individual indications for performing a full mouth examination. More retakes were done with SSDs compared to storage phosphor plates. Reasons for choosing digital techniques were that work was easier and communication with the patients improved. However, dentists also experienced problems with digital techniques, such as exposure and projection errors and inadequate image quality. The Swedish Radiation Safety Authority states that all radiological examinations should be justified, something not always followed., Conclusions: This study showed that 98% of the respondents, Swedish dentists within the Swedish Dental Society, used digital techniques, and the most used was the solid-state technique.

Objectives: Radiographic images suffer from varying amounts of noise. The most studied and discussed of these is random noise. However, recent research has shown that the projected anatomy contributes substantially to noise, especially when detecting low-contrast objects in the images. Our aim, therefore, was to evaluate the extent to which overprojected anatomical noise affects the detection of low-contrast objects in intra-oral images., Methods: Our study used four common sensor models. With each sensor, we took four series of images, three series with and one series without an anatomical phantom present. In each series, we exposed a low-contrast phantom at 18 different exposure times using a standardized method. 4 observers evaluated all 288 images., Results: The low-contrast characteristics differed substantially when imaging low contrast on a homogeneous background compared with imaging low contrast when an anatomical phantom was present. For three of the sensors, optimal exposure times for low-contrast imaging were found, while the fourth sensor displayed a completely different behaviour., Conclusions: Calibrating the low-contrast properties of an imaging system using low-contrast objects on a homogeneous background is not recommended. On an anatomical background, low-contrast properties are completely different, and these will mimic the clinical situation much more closely, directing the operator how to best use the system. There is a clear demand for further research on this subject.

The objectives were to study whether a smaller area of irradiation resulted in a significant reduction in the dose of absorbed radiation to the thyroid gland for three radiographic modalities commonly used in cephalometric treatment planning. The aim of this research, was to study the effect of the field size on the absorbed dose of radiation to the thyroid gland, as measured with thermoluminescent dosimeters (TLD) in a phantom. Three radiographic modalities were used: panoramic, cephalometric, and intra-oral. For each modality, a large and a small collimator were used. A Rando Alderson phantom comprising a natural human cranium and cervical vertebrae embedded in a thermoplastic material simulating human soft tissue was used to measure absorbed dose to the thyroid gland. These measurements were made using lithium fluoride (LiF) TLDs. A significant reduction in absorbed dose to the thyroid gland was obtained by reducing the collimator in all three modalities. A 15% reduction in absorbed dose to the thyroid gland was achieved for the combination of small field sizes compared to the combination of large field sizes. Combining the use of selection criteria together with a smaller field of irradiation than normally used made a reduction in absorbed dose to the thyroid gland of around 30% possible.