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.

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.

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.

Using a planimetric method, the size of horizontal wear facets on maxillary anterior teeth was studied longitudinally in the permanent dentition of 35 subjects at ages 14, 18, and 23?years. The study subjects had not previously undergone any orthodontic treatment and had Class I occlusion. We studied the association between the amount of wear and reported parafunctions and maximal bite force. Total wear areas in age groups 14, 18, and 23 years were 29.5 mm2 (SD 11.4), 39.1 mm2 (SD 12.7), and 45.0 mm2 (SD 13.0), respectively. The total wear area increased significantly both from 14 to 18 years of age and from 18 to 23 years of age (p <0.0001). Between 18 and 23?years of age, the maxillary canines showed strongest wear, although the central incisors had largest wear facets. It can be concluded that wear of permanent anterior teeth is a continuous phenomenon in adolescence and young adulthood.

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.

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 O 2 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.

Obectives: To compare the quality of conventional complete dentures fabricated with two different techniques. A randomized controlled clinical trial was conducted to compare traditional (T) and simplified (S) methods of making complete conventional dentures on patients' ratings of satisfaction, comfort and function at 3 and 6 months following delivery. The quality of the prostheses was rated by prosthodontists at 6 months.Materials and methods: One hundred twenty-two mate and female edentulous individuals, aged 45-75 years, were randomly allocated into groups that received dentures made with either T or S methods. Following delivery, patients' ratings of several denture-related factors were measured using 100 mm visual analogue scales, and denture quality was assessed by blinded prosthodontists using ratings on a validated quantitative scale.Results: There were no significant differences between the two groups in patient ratings for overall satisfaction (3 months: mean T=83 mm, mean S=83 mm, P= 0.97; 6 months: mean T=79 mm, mean S=79 mm, P=0.96) or in prosthodontists' ratings of denture quality (T= 66, S = 63; P= 0. 38).Conclusion: These results show that the quality of complete dentures does not suffer when manufacturing techniques are simplified to save time and materials. Dental educators should consider these findings when re-designing prosthodontic training programs. (c) 2005 Elsevier Ltd. All rights reserved.

To assess the reproducibility of the mandibular cortical index (MCI) on panoramic radiographs among British and Japanese observers, and to investigate the difference between the British and Japanese observers in the definition of MCI.

Purpose: The purpose of this study was to compare clinicians' ratings of the state of oral tissues and their satisfaction with treatment to edentulous patients' ratings of treatment success after provision of mandibular implant overdentures or conventional dentures. Materials and Methods: Sixty subjects randomly received either mandibular overdentures retained by two implants (n = 30) or new conventional mandibular complete dentures (n = 30). All were given new conventional maxillary dentures. Baseline measures included clinical evaluation of the oral soft and hard tissues. Patients rated their general satisfaction before and after treatment, as well as their satisfaction with stability, speech, and esthetics on visual analogue scales. The treating prosthodontist rated the dentures for the same categories. Patient and clinician ratings were compared using correlations, t tests, and linear regression. Results: None of the clinical variables were significantly correlated with patient satisfaction before or after treatment. The prosthodontist rated mandibular implant overdentures significantly better than conventional dentures regarding general satisfaction, stability, speech, and esthetics. implant overdentures were also easier to fabricate (P < .0001). The prosthodontists' scores were not significantly correlated with patient scores for any question. Conclusion: Clinicians' assessments of the quality of denture-supporting tissues are poor predictors of patient satisfaction with mandibular implant or conventional prostheses. Prosthodontists and patients both rate mandibular implant overdentures as significantly superior to conventional dentures, but patients and clinicians do not usually agree when evaluating individual prostheses.

PURPOSE The purpose of this study was to compare elderly patients' satisfaction and oral health-related quality of life with mandibular two-implant overdentures and conventional dentures. MATERIALS AND METHODS Sixty edentulous subjects aged 65 to 75 years were randomly assigned to two groups treated with maxillary conventional dentures and either a mandibular conventional denture (n = 30) or an overdenture supported by two implants with ball retainers (n = 30). Subjects rated their general satisfaction, as well as other features of their dentures (comfort, stability, ability to chew, speech, esthetics, and cleaning ability), prior to treatment and 2 months postdelivery. Changes in ratings on the original Oral Health Impact Profile (OHIP) and its short form (OHIP-EDENT) were also used as indicators of oral health-related quality of life. RESULTS The primary outcome of this study, ratings of general satisfaction 2 months postdelivery, was significantly better in the group treated with mandibular two-implant overdentures (P = .001). In addition, the implant group gave significantly higher ratings on comfort, stability, and ability to chew. Furthermore, using OHIP-EDENT, subjects who received mandibular two-implant overdentures had significantly fewer oral health-related quality of life problems than did the conventional group. CONCLUSION These short-term results suggest that mandibular two-implant overdentures combined with maxillary conventional dentures provide better function and oral health-related quality of life than conventional dentures.

Success rates for titanium dental implants in the anterior mandible are very high. Because of these success rates, as well as lower costs, it is common to treat edentulous patients with just 2 implants and ball anchors for retention of the overdenture, instead of 4 implants and a bar. In this paper the fabrication of 2-implant overdentures is described. In a controlled clinical trial (to be reported elsewhere), 30 subjects received a 2-implant overdenture for the mandible and a conventional prosthesis for the maxilla. The 30 control patients received conventional complete dentures for both jaws. The stability of the overdentures was excellent, and the lingual dimensions of the denture could be reduced to the level of the mylohyoid line to provide more space for the tongue. In patients with tense labial musculature or a limited amount of attached gingiva, it was important to elevate the shoulder of the implant and ball abutment above the gingival level to avoid peri-implant problems. Significantly fewer visits for adjustment related to post-placement pressure spots were required for mandibular overdentures than for conventional mandibular prostheses.

In order for clinicians to effectively manage their practices, they need to know how much time they spent in carrying out procedures. The provision of two-implant overdentures for edentulous patients is becoming more prevalent as increasing evidence demonstrates their great benefit to patients. The aim of this study was to measure the number of visits and the time required during the surgical phase (from pre-op examination to preliminary impressions) of mandibular two-implant overdenture treatment. Thirty edentulous patients were assigned to receive two root-form implants in the mandible between the mental foramen, as part of a randomized controlled clinical trial. All visits and time spent by the oral surgeon, the surgical assistant and the prosthodontist were measured individually. The mean number of scheduled visits with the oral surgeon was four, and the mean time taken was 104 min. The mean time taken by the surgical assistant was 122 min. On average, the prosthodontist was required for two visits, with a total mean time of 36 min. In addition to the scheduled visits, 14 patients solicited additional appointments (unscheduled visits) for various problems (e.g. loose healing cap). The average time taken for unscheduled visits was 32 min. Combining scheduled and unscheduled visits, the mean total time taken by the oral surgeon was 109 min. The surgical assistant was needed for a mean total of 125 min, and the prosthodontist spent, on average, 46 min in this phase of treatment. Results from this study will assist clinicians in establishing the total time and number of visits needed for the surgical phase of two-implant mandibular overdenture treatment.

PURPOSE:In this article, the time taken by a prosthodontist to fabricate and maintain mandibular overdentures retained by two implants and conventional dentures is compared.MATERIALS AND METHODS:Sixty edentulous patients between the ages of 65 and 75 completed a randomized clinical trial. All received new maxillary conventional dentures and either a mandibular conventional denture (n = 30) or a two-implant overdenture on ball attachments (n = 30). The time spent by the prosthodontist and the number of visits required for treatment, including both scheduled and unscheduled visits, were recorded for each patient from preliminary impressions to 6 months following delivery. Data from the two groups were compared using Mann-Whitney U tests.RESULTS:The prosthodontist spent a mean total time of 296 minutes in treating an implant overdenture patient and 282 minutes on a conventional denture patient during the period from preliminary impressions to the 6-month follow-up. The mean numbers of appointments were 10.1 (implant group) and 10.8 (conventional group). These differences were not significant.CONCLUSION:Although additional knowledge is required to treat patients with implant prostheses, the time required by the prosthodontist to provide two-implant mandibular overdentures with ball attachments was not significantly different than the time needed for conventional denture treatment.

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.

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.

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.

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.

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.