Jan Ahlqvist

Implant Treatment of Patients with Edentulous Jaws: A 20-Year Follow-Up

BACKGROUND Implant-supported prostheses are today often used in rehabilitation of partially or totally edentulous patients. Both patients and the dental profession often regard implant treatment as successful in a life perspective. Therefore, studies with a long-term follow-up are important. PURPOSE The aim was to investigate the outcome of implant treatment with fixed prostheses in edentulous jaws after 20 years, with special reference to survival rate of implants and prostheses and frequency of peri-implantitis. MATERIALS AND METHODS The patient material was a group of patients treated in the early 1980s. The original patient group comprised the first 48 consecutive patients treated with implant-supported prostheses at Umeå University. All patients were edentulous in one or two jaws. The patients had a mean age at the implant insertion of 54.3 years (range 40-74). At the planning of this study 20 years after treatment, 19 of the 48 patients were found to be deceased. Of the 29 patients still alive, 21 patients with altogether 23 implant-supported prostheses could be examined clinically and radiographically. All patients were treated ad modum Brånemark (Nobel Biocare AB, Göteborg, Sweden) with a two-stage surgical procedure. The implants had a turned surface. Abutment connections were performed 3 to 4 months after fixture insertion in the mandible, and after a minimum of 6 months in the maxilla. The prostheses were fabricated with a framework of gold alloy and acrylic artificial teeth. RESULTS The 21 patients (with 23 implant prostheses) examined had at the time of treatment got 123 implants (27 in the upper jaw and 96 in the lower jaw) inserted. Only one of these implants had been lost (about 2 years after loading) giving a survival rate of 99.2%. Very small changes occurred in the marginal bone level. Between the 1 and 20-year examinations, the mean bone loss was 0.53 mm and the mean bone level at the final examination was 2.33 mm below the reference point. CONCLUSIONS This follow-up over two decades of implant-supported prostheses demonstrates a very good prognosis for the treatment performed. The frequencies of peri-implantitis, implant failures, or other complications were very small, and the original treatment concept with a two-stage surgery and a turned surface of the implants will obviously give very good results.

Autogenous onlay bone grafts fixed with screw implants for the treatment of severely resorbed maxillae. Radiographic evaluation of preoperative bone dimensions, postoperative bone loss, and changes in soft-tissue profile.

Thirty patients with severely resorbed edentulous maxillae underwent combined treatment of iliac bone onlay graft and titanium implants. The patients were followed for 3 years. They were radiographically examined before surgery to evaluate the bone volume at the intended implant sites. Only 13/156 implant sites were suitable for implant insertion. The bone level at the implant surfaces was evaluated after 6 months and 1, 2, and 3 years, respectively. There was a continuing decrease of the bone level throughout the follow-up period with a mean loss of 4.9 mm after 3 years and with no difference between sexes. Twenty-six implants were radiographically examined before removal, and only three of these implant sites showed radiographic signs of failure. The soft-tissue profile was analyzed cephalometrically by the subtraction technique. The upper lip generally moved inward and the apex of the nose and the columella downward and inward. The anterior facial height increased in most of the patients, resulting in a downward and inward change of the lower lip, the mentolabial sulcus, the soft-tissue pogonion, and the soft-tissue gnathion.

Ultrasound screening for asymptomatic carotid stenosis in subjects with calcifications in the area of the carotid arteries on panoramic radiographs: a cross-sectional study

BackgroundDirected ultrasonic screening for carotid stenosis is cost-effective in populations with > 5% prevalence of the diagnosis. Occasionally, calcifications in the area of the carotid arteries are incidentally detected on odontological panoramic radiographs. We aimed to determine if directed screening for carotid stenosis with ultrasound is indicated in individuals with such calcifications.MethodsThis was a cross-sectional study. Carotid ultrasound examinations were performed on consecutive persons, with findings of calcifications in the area of the carotid arteries on panoramic radiography that were otherwise eligible for asymptomatic carotid endarterectomy.ResultsCalcification in the area of the carotid arteries was seen in 176 of 1182 persons undergoing panoramic radiography. Of these, 117 fulfilled the inclusion criterion and were examined with carotid ultrasound. Eight persons (6.8%; 95% CI 2.2-11.5%) had a carotid stenosis - not significant over the 5% pre-specified threshold (p = 0.232, Binomial test). However, there was a significant sex difference (p = 0.008), as all stenoses were found in men. Among men, 12.5% (95%CI 4.2-20.8%) had carotid stenosis - significantly over the 5% pre-specified threshold (p = 0.014, Binomial test).ConclusionsThe incidental finding of calcification in the area of the carotid arteries on panoramic radiographs should be followed up with carotid screening in men that are otherwise eligible for asymptomatic carotid endarterectomy.Trial Registration: The study was registered at http://www.clinicaltrials.gov; NCT00514644

Detection of calcifications in panoramic radiographs in patients with carotid stenoses ≥50%.

OBJECTIVE Carotid stenoses ≥50% are associated with increased risk for stroke that can be reduced by prophylactic carotid endarterectomy (CEA). Calcifications in arteries can be detected in panoramic radiographs (PRs). In a cross-sectional study, we analyzed (1) extirpated plaques for calcification, (2) how often PRs disclosed calcified plaques, (3) how often patients with stenoses ≥50% presented calcifications in PRs, and (4) the additional value of frontal radiographs (FRs). STUDY DESIGN Patients (n = 100) with carotid stenosis ≥50% were examined with PRs and FRs before CEA. Extirpated carotid plaques were radiographically examined (n = 101). RESULTS It was found that 100 of 101 (99%) extirpated plaques were calcified, of which 75 of 100 (75%) were detected in PRs; 84 of 100 (84%) patients presented carotid calcifications in the PRs, in 9.5% contralateral to the stenosis ≥50%. CONCLUSIONS Carotid calcifications are seen in PRs in 84% of patients with carotid stenosis ≥50%, independent of gender. FRs do not contribute significantly to this identification.

Thin bony walls of the temporomandibular joint. Morphologic properties and tomographic reproduction.

The morphology of two thin bony walls in the medial third of the mandibular fossa is described on the basis of successive microtome sections of undecalcified temporomandibular joint specimens. The requirements for reproduction on thin bony walls at tomography with hypocycloidal movement are defined and discussed.

Atherosclerotic Calcification Detection: A Comparative Study of Carotid Ultrasound and Cone Beam CT

Background and Aim: Arterial calcification is often detected on ultrasound examination but its diagnostic accuracy is not well validated. The aim of this study was to determine the accuracy of carotid ultrasound B mode findings in detecting atherosclerotic calcification quantified by cone beam computed tomography (CBCT). Methods: We analyzed 94 carotid arteries, from 88 patients (mean age 70 ± 7 years, 33% females), who underwent pre-endarterectomy ultrasound examination. Plaques with high echogenic nodules and posterior shadowing were considered calcified. After surgery, the excised plaques were examined using CBCT, from which the calcification volume (mm3) was calculated. In cases with multiple calcifications the largest calcification nodule volume was used to represent the plaque. Carotid artery calcification by the two imaging techniques was compared using conventional correlations. Results: Carotid ultrasound was highly accurate in detecting the presence of calcification; with a sensitivity of 88.2%. Based on the quartile ranges of calcification volumes measured by CBCT we have divided plaque calcification into four groups: <8; 8–35; 36–70 and >70 mm3. Calcification volumes ≥8 were accurately detectable by ultrasound with a sensitivity of 96%. Of the 21 plaques with <8 mm3 calcification volume; only 13 were detected by ultrasound; resulting in a sensitivity of 62%. There was no difference in the volume of calcification between symptomatic and asymptomatic patients. Conclusion: Carotid ultrasound is highly accurate in detecting the presence of calcified atherosclerotic lesions of volume ≥8 mm3; but less accurate in detecting smaller volume calcified plaques. Further development of ultrasound techniques should allow better detection of early arterial calcification.

Collaborative learning with screen-based simulation in health care education: an empirical study of collaborative patterns and proficiency development

This article is about collaborative learning with educational computer-assisted simulation(ECAS) in health care education. Previous research on training with a radiological virtual reality simulato ...

External bony auditory canal and the tympanic bone. Morphologic properties and influences on the tomographic reproduction.

The external bony auditory canal is morphologically defined as concerns the shape and calibre in successive plane parallel histologic sections of the petrous bone. The sagittal dimensions and structural appearances of the tympanic bone are demonstrated. The morphologic properties defined constitute a basis for the evaluation of the tomographic image formation in this region.

Bone demarcation of the temporomandibular joint : Validity of clinical assessment of bone thickness by means of CT

Purpose: To study the CT depiction of bone demarcations in the temporomandibular joint, using conventional window level and window width; and to evaluate observer performance in estimating bone thickness in these images. Material and Methods: Seven joint specimens were imaged by CT and then cryosectioned. the measurements of bone wall thickness in the images were compared to the true bone thickness at each cutting level. In addition, 4 experienced radiologists estimated the thickness of the bone walls in the images. Results: the relative difference between the CT reproduction and the true bone thickness was small for bone walls thicker than 2 mm. This difference increased with the decrease in bone thickness and the increase in the inclination of the bone wall from the perpendicular to the image plane. Bone walls thinner than 1 mm were reproduced as considerably thicker than their true thickness. This resulted in a clinical overestimation of bone thickness. Conclusion: Both the CT representation and the interpretation of bone demarcation in the temporomandibular joint may constitute a problem. Partial volume averaging effects can result in an overestimation of bone dimensions amounting to 200% for thin bones. the central white zone in images of thin bone walls obtained with the parameters described here could serve as an indicator that could help to reduce the risk of overestimating bone thickness.

Carotid calcification in panoramic radiographs: radiographic appearance and the degree of carotid stenosis

OBJECTIVES: Approximately 7% of patients examined with panoramic radiographs (PRs) for odontological reasons, and with incidental findings of carotid artery calcification (CAC), have significant (≥50%) carotid stenosis (SCS). The aim of this study was to determine if the radiographic appearance of CACs in PRs could be categorized such that we could improve the positive-predictive value (PPV) for SCS detection. METHODS: This cross-sectional study included 278 patients with CACs identified by PRs, 127 with SCS and 151 without SCS. CACs were categorized based on the following appearances: (1) single, (2) scattered or (3) vessel-outlining. Correlates were derived for each category according to positivity or not for SCS in the corresponding neck sides. For a representative adult population (in dentistry) presenting with CACs in PRs, PPVs for SCS prediction were then calculated for three subgroups based on different combinations of appearances (2) and/or (3). RESULTS: Vessel-outlining CACs corresponded to 65% of neck sides with SCS vs 47% without SCS (p < 0.001). Single CACs corresponded to 15% of neck sides with SCS vs 27% without SCS (p = 0.006). Scattered CACs corresponded to 20% of neck sides with SCS vs 26% without SCS (p = 0.127). In the representative population, the PPVs for SCS detection were comparable (7.2-7.8%) for all three subgroups and when the presence of a CAC is the sole criterion (7.4%). CONCLUSIONS: Stratifying the radiographic appearance of CACs in PRs does not improve the PPV for SCS detection. Whether different radiographic appearances are associated with future risk of stroke, or other cardiovascular events, remains unknown.