Observer performance in diagnosing osteoporosis by dental panoramic radiographs: results from the osteoporosis screening project in dentistry (OSPD).

Mandibular cortical erosion detected on dental panoramic radiographs (DPRs) may be useful for identifying women with osteoporosis, but little is known about the variation in diagnostic efficacy of observers worldwide. The purpose of this study was to measure the accuracy in identifying women at risk for osteoporosis in a worldwide group of observers using DPRs. We constructed a website that included background information about osteoporosis screening and instructions regarding the interpretation of mandibular cortical erosion. DPRs of 100 Japanese postmenopausal women aged 50 years or older who had completed skeletal bone mineral measurements by dual energy X-ray absorptiometry were digitized at 300 dpi. These were displayed on the website and used for the evaluation of diagnostic efficacy. Sixty observers aged 25 to 66 years recruited from 16 countries participated in this study. These observers classified cortical erosion into one of three groups (none, mild to moderate, and severe) on the website via the Internet, twice with an approximately 2-week interval. The diagnostic efficacy of the Osteoporosis Self-Assessment Tool (OST), a simple clinical decision rule based on age and weight, was also calculated and compared with that of cortical erosion. The overall mean sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the 60 observers in identifying women with osteoporosis by cortical erosion on DPRs were 82.5, 46.2, 46.7, and 84.0%, respectively. Those same values by the OST index were 82.9, 43.1, 43.9, and 82.4%, respectively. The intra-observer agreement in classifying cortical erosion on DPRs was sufficient (weighted kappa values>0.6) in 36 (60%) observers. This was significantly increased in observers who specialized in oral radiology (P<0.05). In the 36 observers with sufficient intra-observer agreement, the overall mean sensitivity, specificity, PPV, and NPV in identifying women with osteoporosis by any cortical erosion were 83.5, 48.7, 48.3, and 85.7%, respectively. The mean PPV and NPV were significantly higher in the 36 observers with sufficient intra-observer agreement than in the 24 observers with insufficient intra-observer agreement. Our results reconfirm the efficacy of cortical erosion findings in identifying postmenopausal women at risk for osteoporosis, among observers with sufficient intra-observer agreement. Information gathered from radiographic examination is at least as useful as that gathered from the OST index.

Implants and/or teeth: consensus statements and recommendations.

In August 23-25, 2007, the Scandinavian Society for Prosthetic Dentistry in collaboration with the Danish Society of Oral Implantology arranged a consensus conference on the topic 'Implants and/or teeth'. It was preceded by a workshop in which eight focused questions were raised and answered in eight review articles using a systematic approach. Twenty-eight academicians and clinicians discussed the eight review papers with the purpose to reach consensus on questions relevant for the topic. At the conference the consensus statements were presented as well as lectures based on the review articles. In this article the methods used at the consensus workshop are briefly described followed by the statements with comments.

Is there a certain number of implants needed to retain an overdenture?

The aim of this systematic review was to determine if there are reasons to recommend a certain number of implants for retaining or supporting maxillary or mandibular overdentures. Literature search for this review covered clinical trials, randomized controlled-clinical trials, meta-analyses and review articles in English dental journals from 1990 to 2007. The search produced 1779 articles, of which the abstracts of 182 studies were reviewed and those with any exclusion criterion were removed. The remaining 39 full articles were reviewed against the inclusion criteria for finalizing the selection. Eleven research reports meeting the inclusion criteria were selected for this review; three for the maxilla and eight for the mandible. According to this data, in the maxilla and in the mandible, patient satisfaction or function of the prosthesis are not dependent on the number of implants or type of attachment. In the mandible, an overdenture with two implants and with bar attachment has the least number of complications.

Shade selection performed by novice dental professionals and colorimeter.

The objective of this study was to test inter-observer variability in shade selection for porcelain restorations, using three different shade guides: Vita Lumin Vacuum, Vita 3D-Master and Procera. Nineteen young dental professionals acted as observers. The results were also compared with those of a digital colorimeter (Shade Eye Ex; Shofu, Japan). Regarding repeatability, no significant differences were found between the three shade guides, although repeatability was relatively low (33-43%). Agreement with the colorimetric results was also low (8-34%). In conclusion, shade selection shows moderate to great inter-observer variation. In teaching and standardizing the shade selection procedure, a digital colorimeter may be a useful educational tool.

Short duration hyperbaric oxygen treatment effects blood flow in rats: pilot observations.

Hyperbaric oxygen (HBO) treatment has been found to improve healing in living tissues, especially those poor in oxygen. The effects of HBO have also been tested in rat experiments. However, oxygen partial pressure in rat's arterial blood is normally about twice that in humans. Disregarding this, a human HBO protocol has been applied in previous rat experiments with HBO. Laser Doppler flowmetry (LDF) is a non-invasive means for measuring blood flow. Using LDF, we measured the blood perfusion rate in rats receiving HBO, according to a modified protocol, in a region of healing soft tissue with bone defect. The results indicate that, in rats, shorter HBO treatment with high O2 pressure can significantly improve the blood flow of healing tissues. In this study, an elevated blood perfusion rate was still evident 2 weeks after the ending of HBO therapy, which indicates improved revascularization in the wound area. A short HBO protocol would save time and effort in future HBO experiments on rats.

Position of teeth on the edentulous atrophic maxilla.

For prosthetic treatment of strongly atrophic alveolar wall, some biometric methods have been developed. The measurements taken from plaster cast models of 230 edentulous, average 29.9 years, and 125 dentulous post-menopausal women were correlated. In the edentulous maxilla the sagittal position of canine teeth can be determined by the oral edge of incisive papilla. The transverse position of canine teeth was on the outer edge of the alveolar wall because of the extensive loss of buccal alveolar bone. On the incisor area the facial surfaces of the central incisors were determined by the oral edge of incisive papilla and the distance was about twice the length of the papilla. The sagittal position of the first premolars was one-third and the first molars two-thirds the length of the palate from the plane of the labial edge of incisive papilla. The transverse position of the premolars and molars was determined by the scar-line, which is a cord-like elevation or track on the alveolar mucosa after extractions of the teeth. According to the comparative method, the position of the scar-line differed from the lingual gingival margin line and was situated about half breadth of the tooth in a buccal direction from it. The transverse position of premolar and molar in the edentulous maxilla is about the middle of the scar-line in a facio-buccal direction. In the setting of the artificial teeth, the facial surfaces of these teeth should be on average 5.0-6.0 mm sideways from the scar-line, whilst the total bilateral breadth of the alveolar wall in the sulcus area was on average 1.0-2.0 mm larger.

The reproducibility of the mandibular cortical index.

OBJECTIVES: To assess the reproducibility and diagnostic validity of Mandibular Cortical Index (MCI) when used by minimally trained observers. METHODS: Four 'experts' and 45 final-year dental students classified the appearance of the lower border of the mandibular cortex in 30 panoramic radiographs using the MCI. Experts viewed the original radiographs. The students received instruction in the MCI and viewed slides of the radiographs in a lecture theatre. RESULTS: For intra-observer agreement, the experts had significantly higher overall values of weighted kappa, indicating substantial agreement in MCI assessment, whereas the students showed moderate agreement. For inter-observer agreement, there was fair agreement between the experts and poor agreement between the students. Using the experts' MCI assessment as the 'gold standard', the mean sensitivity of the students in diagnosis of C3 was 0.71 (maximum 0.95, minimum 0.25) and mean specificity was 0.56 (maximum 0.9, minimum 0.20). CONCLUSIONS: The MCI has important limitations in terms of intra- and inter-observer agreement. Minimal training in its use, such as might be given in a lecture format to dentists, was ineffective and associated with poor inter-observer agreement and limited diagnostic validity in identifying signs of osteoporosis. More lengthy training and experience in using the MCI would be needed for it to be effective as a diagnostic tool in general dental practice.

Osseointegration of dental implants in bone irradiated with 40, 50 or 60 gy doses. An experimental study with beagle dogs.

Construction of different kinds of prostheses on irradiated bone tissues after tumour surgery is a complicated part of modern implantology. In irradiated regions of the jaws where the bone layers are thin and the blood supply also is minimal, knowledge of the impact of each dose of radiation is very important. The aim of this study was to compare the bone response around titanium implants loaded with fixed bridges in dog mandibles irradiated with total doses of 40, 50 or 60 Gy. The results suggest that after irradiation with 40-50 Gy, when the dose is fractioned in order to achieve higher tolerance of the tissues compared with single dose irradiation, titanium implants may become osseointegrated in the mandibles. For high success rates, however, careful planning of radiotherapy and selection of implantation site with an adequate blood supply are essential.

Fluoridated drinking water, oestrogen therapy and residual ridge resorption.

Anamnestic and clinical investigations were made for 230 postmenopausal women to determine whether the alveolar height in edentulous jaws is associated with the time that the subjects have consumed artificially fluoridated drinking water. The duration of possible hormone replacement therapy was also considered. The results of the present study support those of previous studies which have shown that the effect of systemic factors dominates the final stage of residual ridge resorption. According to this study, artificially fluoridated water may also reduce the degree of residual ridge resorption, the impact of which first becomes manifest when most of the ridge has disappeared.

Morphology of the mandibular cortex on panoramic radiographs as an indicator of bone quality.

OBJECTIVES: To determine whether the bone mineral density (BMD) of the mandibular cortex is correlated with an ordinal classification of the morphology of the inferior cortex on panoramic radiographs. METHODS: The cortical BMD of the mandible was measured by single-energy quantitative computed tomography at two sites: (1) buccally and distally from the mental foramen, (2) lingually and distally from the mental foramen. The morphology of the mandibular cortex was assessed on panoramic radiographs, and classified into three groups. RESULTS: The severity of the changes in the mandibular cortex was significantly related to the BMD of the buccal cortex (ANOVA: p = 0.002). CONCLUSIONS: The use of an ordinal classification of the mandibular cortex on panoramic radiographs may be helpful for general dental practitioners in the assessment of the local quality of the cortical bone.

Relationship between body mass index and the remaining alveolar ridge.

Severe residual ridge resorption may occur in individuals with either high or low mineral density in the skeleton. Heavy individuals with a heavy skeleton and a large percentage of fat in the body are less predisposed to osteoporosis than small individuals are. In addition, the jaws of heavy subjects are probably more massive and thick than the jaws of smaller individuals. The purpose of this study was to examine whether, after a long period of edentulousness, the size of the subject is associated with the height of the remaining alveolar ridge and difficulties in wearing complete dentures. The conclusions of this study suggest that the size of an individual may play an important role in the destiny of the residual ridges. Heavy subjects with large jaws have more bone substance to be lost. Wider supportive tissues in the mandible also may provide better possibilities for the use of complete dentures than do the jaws of small individuals.

Titanium implants and lateral forces. An experimental study with sheep.

The purpose of this study was to investigate the resistance of titanium implants to horizontal forces in a sheep model. Twenty implants were inserted into the foreheads of 5 sheep, 4 implants on each animal. After a healing period of 3 months, abutments were mounted on the implants. After a further healing period of 3 weeks, the implants were loaded with a horizontal pull of orthodontic elastics. The force varied between 250 and 350 grams. The duration of loading was 3 months. After the loading period the animals were sacrificed and the forehead bones with implants were fixed in formalin and evaluated histologically. In the histological specimens no signs of infection or bone loss were found around the implants. The results of the present study encourage the use of titanium implants also in cases where constant lateral forces are present.

A review of residual ridge resorption and bone density.

Residual ridge resorption is a common and often incapacitating problem, particularly for persons with edentulous mandibles. Several studies suggest a correlation between ridge resorption and osteoporosis. Recent radiologic studies indicate that the mineral density of the cortex and the bone mass in the mandible are correlated with skeletal bone density. Most resorption occurs in the alveolar process, whereas the basal portion remains relatively intact. On the other hand, radiologic measurements of bone density primarily yield information after the basal portion, where the bone mass of the mandible is greatest and functional stresses of mastication may affect bone density. Ironically, radiologic measurements may not accurately indicate the effect of osteoporosis on alveolar resorption. Apparently, excessive occlusal force can also produce extensive atrophy without systemic impact. Not until muscular function decreases does real osteoporosis develop in edentulous jaws. Not only does the volume of the ridge decrease, but also the density of the basal portion decreases as a result of diminished function. This article reviews the literature on residual ridge resorption and components that may affect the rate of resorption.

Signs of temporomandibular dysfunction related to edentulousness and complete dentures: an anamnestic study.

Symptoms of temporomandibular dysfunction (TMD) are prevalent among elderly individuals with complete dentures. In the agrarian areas of middle Finland it was, as recently as a few decades ago, almost a tradition to extract teeth during young adulthood. Women who today are in post-menopausal age are the last sizable age group in Finland where the problems of edentulousness can be investigated. The purposes of this study were twofold. First, postmenopausal women who are edentulous in the maxilla or totally edentulous were studied to determine if they differ from women with natural teeth in both jaws in terms of subjective TMD symptoms. Second, these subjective symptoms were examined to discover any correlation with duration of edentulousness, age of the dentures, or difficulties in wearing them. The results suggest that for postmenopausal women, clicking noises in the temporomandibular joint and tension in the neck are more common complaints among denture wearers than among those who still have natural teeth. Factors that make the wearing of complete dentures more difficult may also predispose the wearer to TMD symptoms. Duration of edentulousness is not, however, related to the prevalence of anamnestic TMD symptoms.

Biometric design of complete dentures related to residual ridge resorption.

The aim of this study was to determine whether the location of the incisive papilla, the extent of the alveolar bone remaining on the facial side of the palatal-gingival margin in the canine region, and the height of the palatal vault in the molar region are associated with factors that may affect the volume of the residual ridges in an edentulous maxillae. Results suggest that duration of the edentulousness and skeletal mineral status are important factors in the resorption of the residual ridges in the maxillae. The location of the incisive papilla and the thickness of the ridge on the facial side of the palatal-gingival margin are associated with these two factors.

Craniomandibular disorders, edentulousness and the clinically estimated size of the masseter muscle.

A total of 355 postmenopausal women were classified according to the degree of edentulousness, and anamnestic information on masticatory dysfunction symptoms was recorded. Five masticatory muscles were palpated, and the subjects were classified according to size of the masseter muscle. This simple classification for the clinical inspection of the masseter muscle was tested. In agreement with previous reports, decreasing functional exercise of the jaws was found to diminish the size of the masticatory muscles making them more disposed to dysfunction symptoms. The three-level classification of size of the masseter muscle is useful in normal clinical practice for determining the condition of this muscle.

Craniomandibular disorders and skeletal mineral status.

Values for bone mineral density of the femoral neck and lumbar spine were determined by dual-energy x-ray absorptiometry for 355 postmenopausal women 48 to 56 years of age. The bone mineral density in three regions of the mandible was measured by quantitative computed tomography for 77 of the 355 women. Existing symptoms of craniomandibular dysfunction were recorded in both an anamnestic inquiry and a clinical examination. The purpose of this study was to determine whether the bone mineral density of the skeleton and mandible is associated with symptoms of craniomandibular dysfunctions. The results suggest that the habits and conditions that provoke development of general bone loss in the skeleton may disturb the functional harmony of the masticatory system and, thus, increase the possibility for craniomandibular disorders (CMD).

Resistance of the maxillary ridge to occlusal trauma.

Histories and clinical evaluations were obtained from 230 postmenopausal women aged 48 to 56 years to determine whether the alveolar height in the edentulous anterior region of the maxillae is adversely affected by the presence of mandibular incisors. Many of these women lost their teeth in early adulthood. When all subjects were included, the height of the ridge in the anterior region of the maxillae was not significantly altered by presence of mandibular incisors. When the ridge height was compared among those who had been edentate in the maxillae for less than 30 years, the difference between dentate and edentate subjects was significant. This study indicates that the alveolar ridges in the anterior region of the maxillae where teeth were extracted early in life during the rapid phase of bone metabolism are less disposed to bite trauma caused by the presence of the mandibular incisors than are individuals who lost their teeth in middle or old age.

Muscle strength and mineral densities in the mandible.

Bone mineral density (BMD) in the femoral neck and lumbar spine was measured for 355 postmenopausal 48- to 56-year-old women and the BMD in five different regions in the mandible for 77. All 355 women were also classified according to the size of the masseter muscle. Both skeletal measures and the BMD of the buccal cortex distally from the foramen mentale were compared with the size of the masseter muscle. This study indicates that functional stress, caused by the masseter muscle, is involved in maintaining bone mineral density in edentulous regions of the mandible. Those individuals who are physically active or are bruxists may lose less mineral, after extractions of teeth, from those regions of the jaw bones where the muscles are attached.

Oral and dental manifestations in gastroesophageal reflux disease.

One hundred seventeen patients with reflux disease were examined with respect to the severity of their disease and oral, dental, and salivary findings. Twenty-eight patients had dental erosion, whereas the remaining 89 patients did not. No mucosal changes could be observed to be linked with the reflux disease. In the mean, the patients with erosion were older (54 versus 49 years), and the mean duration of their reflux disease was longer in comparison to those without erosion (17 versus 11 years, respectively). The severity of the reflux disease was more marked among patients with erosion than in those without as assessed by esophagogastroduodenoscopy, the Maratka classification, histologic examination of gastric and esophageal biopsy specimens, and 24-hour esophageal pH monitoring. No statistically significant differences were observed between the groups in any salivary parameters studied, although the number of patients with low salivary-buffering capacity was higher among those with erosion than among those without. Patients taking beta-blocking agents or tranquilizers had more erosion than those who did not take these medications. The severity of the reflux disease was not associated with any subjective symptoms in the mouth or pharynx. The frequency of consumption of acidic drinks and foodstuffs as determined by a questionnaire did not differ between the patients with and without dental erosion. Thus severe reflux disease of long duration was found to be potentially detrimental to the teeth, whereas milder forms of the disease need not cause dental side effects.