Survival time analysis of remaining teeth following replacement of unilateral free-end missing teeth: A comparison between fixed implant-supported prostheses and removable partial dentures

OBJECTIVES

This retrospective study aimed to investigate the differences in tooth loss rate between fixed implant-supported prostheses (FISPs) and removable partial dentures (RPDs) in cases of unilateral free-end missing teeth.

MATERIALS AND METHODS

The data of 324 patients who underwent treatment with FISPs or RPDs for unilateral free-end missing teeth and satisfied the applicable criteria, were evaluated (47 in the FISPs group and 277 in the RPDs group). After propensity score (PS) matching, which was used to extract patients with similar background factors related to prosthetic selection at baseline, survival time analyses were performed with tooth loss as the endpoint. The adjusted variables were age, sex, number of restored teeth, periodontal status, and the practicing dentist's experience in years. The remaining teeth were classified into subcategories in relation to the missing molars.

RESULTS

Overall, 58 patients (29 in each group) selected by PS matching were evaluated in the final analysis. The total number of lost teeth was 35 (FISPs group: n = 10; RPDs group: n = 25). The mean (±SD) period to tooth loss and the 10-year survival rates in the FISPs and RPDs groups were 51.6 (±30.1) months and 42.3 (±29.7) months, 70.5% and 16.4%, respectively. The log-rank test showed that significantly longer survival time in FISPs compared with RPDs.

CONCLUSIONS

After adjustments for confounding factors using PS matching, replacing unilateral free-end missing teeth with FISPs may exhibit a lower tooth loss rate in adjacent and contralateral teeth compared to replacing with RPDs.

Histologic evaluation of edentulous alveolar ridge horizontal bone augmentations using a xenogeneic bone substitute and autologous platelet concentrates: a case series

OBJECTIVES

This case series aimed to assess the efficacy of a novel horizontal ridge augmentation modality using histology. Combinations of "sticky bone" and tenting screws without autologous bone were used as augmentative materials.

METHOD AND MATERIALS

Five individuals presenting healed, atrophic, partially edentulous sites that required horizontal bone augmentation before implant placement were enrolled. Patients underwent the same augmentation type and 5 months of postoperative reentry procedures. The first surgery served as implant site development, whereas the biopsy and corresponding implant placement were performed during reentry. The bone was qualitatively analyzed using histology and histomorphometry and quantitatively evaluated using CBCT.

RESULTS

Four individuals healed uneventfully. Early wound dehiscence occurred in one case. Histology showed favorable bone substitute incorporation into the newly formed bone and intimate contact between de novo bone and graft material in most cases. Histomorphometry revealed an average of 48 ± 28% newly formed bone, 19 ± 13% graft material, and 33 ± 26% soft tissue components. The CBCT-based mean alveolar ridge horizontal increase was 3.9 ± 0.6 mm at 5 months postoperatively.

CONCLUSIONS

The described augmentation method appears suitable for implant site development resulting in favorable bone quality according to histology. However, clinicians must accommodate 1 to 2 mm of resorption in augmentative material width at the buccal aspect.

Clinical Measurements of Force Exerted on Anterior Teeth in Partial Edentulous Distal Extension

PURPOSE

To determine the influence of partial edentulous distal extension and the use of removable partial dental prostheses in partially edentulous areas on the force exerted on the anterior teeth.

MATERIALS AND METHODS

A total of 83 volunteer patients participated in this study. The occlusal force was measured using an occlusal force measuring sheet in the patient's mouth. The occlusal forces and ratios were compared using the Wilcoxon signed-rank test (P < .05).

RESULTS

The force exerted on the anterior teeth increased significantly as the number of remaining teeth decreased in an edentulous distal extension. The force exerted on the anterior teeth decreased significantly with the use of a removable partial dental prosthesis.

CONCLUSIONS

In a clinical setting, when the number of remaining teeth in a partial edentulous distal extension decreases, the burden on the anterior teeth increases. Our findings suggest that, for patients with partial edentulous distal extension, using a removable partial dental prosthesis is effective in preserving the residual anterior teeth by reducing excessive force.

TranSDFNet: Transformer-Based Truncated Signed Distance Fields for the Shape Design of Removable Partial Denture Clasps

The ever-growing aging population has led to an increasing need for removable partial dentures (RPDs) since they are typically the least expensive treatment options for partial edentulism. However, the digital design of RPDs remains challenging for dental technicians due to the variety of partially edentulous scenarios and complex combinations of denture components. To accelerate the design of RPDs, we propose a U-shape network incorporated with Transformer blocks to automatically generate RPD clasps, one of the most frequently used RPD components. Unlike existing dental restoration design algorithms, we introduce the voxel-based truncated signed distance field (TSDF) as an intermediate representation, which reduces the sensitivity of the network to resolution and contributes to more smooth reconstruction. Besides, a selective insertion scheme is proposed for solving the memory issue caused by Transformer blocks and enables the algorithm to work well in scenarios with insufficient data. We further design two weighted loss functions to filter out the noisy signals generated from the zero-gradient areas in TSDF. Ablation and comparison studies demonstrate that our algorithm outperforms state-of-the-art reconstruction methods by a large margin and can serve as an intelligent auxiliary in denture design.

Removable partial dentures and mortality among partially edentulous adults

OBJECTIVES

The aim of this study was to evaluate whether the use of removable partial dentures (RPDs) has an effect on long-term survival outcomes amongst partially edentulous adults.

METHODS

Data were extracted from the Third National Health and Nutrition Examination Survey and linked to public-use mortality files for the period up to 2019. Partially edentulous adults with fewer than 20 teeth were included. RPD use and dentition status were determined by clinical examination. The cohort was propensity score weighted to create a sample which was balanced across 27 covariates (sociodemographics, health behaviors and insurance, laboratory markers, and general health status). Survival analysis was undertaken to compute absolute (mortality rate and median survival time) and relative (event time ratio [ETR]) measures of exposure effect.

RESULTS

The analyzed cohort included 1246 participants, which equated to 22,557 person-years of follow-up. The difference in all-cause mortality rate between RPD wearers and non-wearers was found to be -6.5 (95% CI: -11.6 to -1.4), with the median survival time in RPD wearers being 3.1 years longer (20.3 years versus 17.2 years). A 26% increase in survival time was observed in RPD wearers (ETR: 1.26, 95% CI: 1.17 to 1.37) and it was found that, for every 7.5 individuals treated with RPDs, one death would be prevented after 10 years of treatment.

CONCLUSIONS

The use of RPDs may have long-term benefits in reducing mortality amongst adults with a non-functional dentition, but further research is needed to validate these findings and assess the factors mediating the relationship.

CLINICAL SIGNIFICANCE

The use of RPDs may have long-term benefits in reducing mortality amongst adults with a non-functional dentition.

Tooth replacement options for partially dentate older adults: a survival analysis

OBJECTIVES

To compare the success of two different tooth replacement strategies for partially dentate older adults; namely resin bonded bridgework (RBB) provided to restore patients according to the principles of the shortened dental arch concept (SDA) and conventional full-arch rehabilitation with removable dental prostheses (RDPs).

METHODS

A randomised controlled clinical trial (RCT) was conducted with partially dentate adults aged 65 years or older. Each patient from the RDP group had all missing natural teeth replaced with cobalt-chromium framework RDPs. Each patient from the SDA group was restored to 10 occluding pairs of natural and replacement teeth using RBB. Patients were followed-up at 6, 12, 24, 36 months. Success rates were generated according to defined success criteria. Log-rank tests and Cox's proportional hazard models were used to compare the success of the two treatment strategies.

RESULTS

After 36 months, 89 patients completed the RCT; n = 45 in the RDP group and n = 44 in the SDA group. The overall success rate of the SDA treatment was 90.4% compared to 73.0% for RDPs (p = 0.005). In the upper arch SDA treatment was 100% successful compared to 86.4% for RDPs (p = 0.019). In the lower arch, lower success rates were reported for both the SDA treatment (80.0%) and RDPs (60.0%) (p = 0.054). Further analyses with cox's proportional hazard models demonstrated that SDA treatment was significantly more successful than RDPs (Hazard Ratio: 2.47, p = 0.04).

CONCLUSIONS

After 36 months SDA treatment using RBB was significantly more successful than RDPs used for conventional full-arch rehabilitation in partially dentate older adults.

CLINICAL SIGNIFICANCE

Functionally orientated treatment according to the principles of the SDA is a feasible alternative to RDPs for partially dentate older patients. SDA treatment using RBB can achieve higher success rates compared to RDPs in this patient group.

Functionally Orientated Tooth Replacement for Older Patients

Across the globe the population is ageing. In addition, older patients are retaining increasing numbers of natural teeth into old age. Therefore, clinicians are faced with the challenges of managing chronic dental diseases, including caries and periodontal disease, alongside replacing missing units. A number of treatment options are available to replace missing teeth for such patients with large numbers currently receiving removable partial dentures. Alternative approaches to treatment should be considered for this population group, including functionally orientated tooth replacement according to the principles of the shortened dental arch concept. In correctly chosen cases, this approach can provide patients with an acceptable, functional and aesthetic reduced dentition. Additionally, evidence suggests that such an approach can significantly reduce the maintenance burden for patients and clinicians which can ultimately deliver a more cost effective solution compared to removable alternatives.

Influence of mandibular free-end partial edentulism on the force exerted on maxillary anterior teeth

PURPOSE

The purpose of this study was to determine the influence of mandibular free-end partial edentulism and the wearing of removable partial dentures in the partially edentulous area on the force exerted on maxillary anterior teeth.

METHODS

A commercially available jaw model with exchangeable teeth was used. Seven experimental conditions of mandibular free-end edentulism were set up and a distal extension removable partial denture to replace missing posterior teeth was fabricated. Strain gauges were attached to the root surface of the maxillary left central incisor, canine, first premolar and first molar, and the force exerted on them was calculated based on the calibration coefficient. An occlusal load of 49 N was applied and the forces were compared with the Kruskal-Wallis test (P < 0.05).

RESULTS

The force exerted on the maxillary anterior teeth increased significantly as the number of remaining teeth decreased. The force exerted on the maxillary anterior teeth decreased significantly with use of a removable partial denture.

CONCLUSIONS

When the number of remaining teeth decreases in mandibular free-end partial edentulism, the burden on the maxillary anterior teeth increases. Our findings suggest that for patients with mandibular free-end partial edentulism, wearing a removable partial denture is effective in preserving the remaining teeth by reducing excessive stress.

Dental Implants for Patients with Periodontitis

This article provides a narrative review of the use of dental implants in patients with periodontitis. using clinical examples where possible, consideration is given to the survival and success of implants, peri-implantitis, comparison of periodontally compromised teeth to implants and to treatment planning to help achieve favourable outcomes.<br/> The challenges associated with restoring an edentulous arch or partially dentate dentition with implants where significant alveolar atrophy has occurred can be considerable. Compromised outcomes may be commonplace.<br/> Dental implant treatment is more likely to be successful for those patients who attain and maintain excellent plaque control. Professional support should focus on managing underlying periodontitis prior to commencing implant therapy and providing long term, regular supportive periodontal care upon completion of treatment.

Interocclusal Records in Fixed Prosthodontics

An accurate interocclusal record is essential for the successful delivery of fixed prosthodontic restorations. There are various materials and techniques used to obtain an interocclusal record in order to facilitate mounting of the dental casts on an articulator. The interocclusal record describes the vertical and horizontal relationship of the maxillary and mandibular teeth. In circumstances where the vertical relationship is not supported through a tripod of widely spaced opposing contacts, the interocclusal record will be needed to restore this vertical support to prevent inaccurate mounting. The clinician should understand when an interocclusal record is required and have an awareness of the different materials and techniques available to record an interocclusal registration.

Guided biopsy of osseous pathologies in the jaw bone using a 3D-printed, tooth-supported drilling template

Suspicious radiological findings in the jaw bone require histopathological examination for the confirmation of a diagnosis. As pathologies in this region are difficult to reach or are in close proximity to relevant anatomical structures, e.g. tooth roots or nerves, they often represent a challenge. Such factors may adversely affect the predictability of the surgical outcome of a biopsy of the osseous tissues. This technical note introduces a novel method for performing a digitally planned, guided biopsy. For this purpose, a cone beam computed tomography scan and an intraoral scan are superimposed using specific planning software. The resulting three-dimensionally printed, tooth-supported drilling template is designed for a trephine biopsy. It allows a precise, minimally invasive approach, with an exact three-dimensional determination of the biopsy location prior to surgery. The risk of devitalization of the neighbouring teeth or possible damage to the nerve structures can be minimized. Furthermore, a small access flap can be sufficient. In summary, the method of bone biopsy presented here allows high precision and greater predictability for biopsy sampling and is minimally invasive for the patient.

Revisiting the Removable Partial Denture

The partial edentulous population is increasing because of an increasing aging population, increased life expectancy, and individuals retaining more teeth at an older age. Therefore, the need for fixed and removable partial denture (RPD) therapy will remain high and will continue into the future. RPDs provide minimally invasive, cost-effective, timely care, and are preferred to fixed dental prostheses using teeth or implant therapy in many clinical scenarios. This article discusses RPD classification systems to review basic concepts and special framework design considerations, and explores advancements in the field such as implant-assisted RPD, CAD/CAM RPD, and new polymer framework materials.

Prosthodontic Treatment Outcomes in Periodontally Compromised Patients: A 6- to 20-Year Long-Term Cohort Study

PURPOSE

To report and analyze long-term treatment outcomes in a patient cohort with severe periodontal disease treated with an employed protocol combining use of implants and double-crown prosthetic support.

MATERIALS AND METHODS

A convenience sample of 16 patients with generalized severe periodontal disease were prosthodontically managed with support from 83 dental implants and 21 removable prostheses using a double-crown concept (11 implant-tooth supported and 10 implant supported). Each patient was examined 2 to 4 weeks before scheduled teeth extraction and examined again following treatment completion at the time of insertion of the superstructures. Subsequent recall examinations were performed every 3 months over a 6- to 20-year period. Predetermined clinical parameters were recorded at each session, and intraoral radiographs were taken after insertion of the superstructure and at intervals of 1, 3, 5, 10, and 20 years.

RESULTS

No implant or tooth loss occurred during the individual observation periods. Mucositis was recorded around 65% of the implants and was accompanied by additional maxillary marginal bone loss around 27.7% of the implants. Mean marginal bone loss at implant sites after 5 years was 0.75 ± 0.66 mm, and after 20 years was 1.50 ± 1.45 mm. Moderate bone loss around teeth was registered after 5 years (2.8%) and 20 years (7.3%). No significant differences were found between implants in patients with tooth-implant-supported and those with implant-supported double-crown restorations.

CONCLUSION

These results suggest that severely periodontally compromised patients can be successfully managed in the long term with the described clinical protocol.

IMPROVED DESIGN OF TEMPORARY PROSTHESIS FOR THE BONE AUGMENTATION AND TWO-STAGE DENTAL IMPLANTS OSSEOINTEGRATION PERIOD

The study was performed on 21 edentulous patients, treated during the period of 2017 - 2018 at the Surgical Dentistry Department at the Moscow State University of Medicine and Dentistry. The patients underwent the procedures of bone augmentation, dental implant placement, and placement of various design temporary dentures for the periods preceding the placement of the permanent implant-supported dentures. The authors have developed and implemented a medical-prophylactic device - an acrylic partial denture supported by temporary dental implant and Klammer fixation on the existing crowns in front of the edentulous area. The results of the use of the device during the post-operative period were analyzed and compared to those of traditionally designed removable partial devices. The comparative analysis has shown that the medical-prophylactic device is superior to the temporary removable partial dentures and vacuum-formed retainers.

[Implant surgery in partially edentulous patients with alveolar bone deficiency]

The article presents the analysis of possible options of dental implant surgical treatment of partially edentulous patients with insufficient alveolar bone volume in the period from 2008 to 2017 (n=1004). Highlighted are three main options for surgical treatment: a staged approach, including alveolar ridge augmentation, subsequent dental implantation (n=562); dental implantation with simultaneous alveolar ridge augmentation (n=362); using of 'narrow/short' dental implants (n=80). The data on the frequency of intra - and postoperative complications before prosthetics are given. Over the past period, there has been a declining tendency in the number of staged procedures with an increase in the number of simultaneous operations installations of 'narrow/short' implants.

Versatility of Overpartial Abutments Key to Economical Restoration of Patient's Smile

Combination syndrome (CS) is a dental condition commonly seen in patients with a completely edentulous maxilla and partially edentulous mandible with preserved anterior teeth. Overgrowth of the tuberosities, papillary hyperplasia of palatal mucosa, and decreased occlusal vertical dimension are typically associated with this syndrome. This article describes a case report where the patient was showing initial signs of CS with irritation from an ill-fitting maxillary denture and a loose mandibular acrylic partial denture. As part of the treatment, implant-supported abutments were used to stabilize the maxillary denture, and implants were placed in the posterior mandible to prevent further resorption. The case demonstrates the use of LOCATOR R-Tx® abutments (Zest Dental Solutions) to enable the patient to regain her smile and confidence, showing the versatility of these overpartial abutments.

Biological complications of removable dental prostheses in the moderately reduced dentition: a systematic literature review

OBJECTIVES

The aim of the present study was a systematic review and subsequent meta-analysis on biological complications of removable prostheses in the moderately reduced dentition.

MATERIALS AND METHODS

A systematic literature search in established medical databases (MEDLINE, EMBASE, BIOSIS, SciSearch, Cochrane, FIZ Technik Web) and a hand search of relevant dental journals was conducted. The search terms were relevant MeSH terms, free search terms, and combinations of the two. The search included randomized controlled trials, prospective and retrospective studies with data on biological complications of removable dental prostheses in the moderately reduced dentition with at least 15 participants, an observation period of at least 2 years, and a drop-out rate of less than 25%. The selection of relevant publications was carried out at the title, abstract, and full-text level by at least two of the authors involved. The publications included were tabulated and analyzed.

RESULTS

Of the original 12,994 matches, 1923 were analyzed by title, 650 by abstract, and 111 according to the full text. A total of 42 publications were ultimately included. The following parameters were evaluated.

TOOTH LOSS

Results varied, depending on the observation period, between 0 and 18.1% for clasp-retained removable dental prostheses (RDPs), between 5.5 and 29% for attachment-retained RDPs, and between 5.5 and 51.7% for double crown-retained RDPs.

CARIES

Results varied, depending on the observation period, between 0 and 32.7% for clasp-retained RDPs, between 1.8 and 29% for attachment-retained RDPs, and between 1.8 and 16.4% for double crown-retained RDPs.

ENDODONTIC TREATMENT

Results varied, depending on the observation period, between 3.5 and 19.2% for clasp-retained RDPs, between 6.9 and 16.4% for attachment-retained RDPs, and between 0.6 and 13.9% for double crown-retained RDPs.

TOOTH FRACTURE

Results varied, depending on the observation period, between 1.7 and 5.3% for clasp-retained RDPs, between 12.7 and 40% for attachment-retained RDPs, and between 0.4 and 4.4% for double crown-retained RDPs.

TOOTH MOBILITY

There were no changes or improvements for clasp-retained RDPs. The better the pre-treatment and supportive care is, the smaller the differences are. For double crown-retained RDPs, a slight increase was found in one study. The results for the parameters probing depth and radiological bone loss were inconclusive.

GINGIVAL RECESSION

Gingival recession seemed to be favored by a mandibular sublingual bar. Compared to fixed restorations, removable restorations seemed to be associated with a more pronounced need for dental treatment. Stringent pre-treatment and supportive care reduced the complication rates.

CONCLUSIONS

Heterogeneous study designs and data analyses rendered a meta-analysis impossible, so that an evaluation at the highest level of evidence could not be performed.

CLINICAL RELEVANCE

Within the limitations of this study, it would be correct to state that removable dental prostheses require intensive maintenance. Suitable pre-treatment and supportive care can lower the complication rates, in the absence of which they constitute trigger factors for (additional) biological complications.

[Iatrogenic, intrinsic irritation of the oral mucosa]

The behaviour of a 78-year-old, edentulous female resident of a care home, suffering from dementia indicated to her care providers that she was experiencing oral pain. At the left (pre)molar region of the mandibular residual alveolar ridge, an irritated, red-coloured, sharply restricted mucosal area was seen, extending in width from the buccal to the lingual border of the ridge. Eventually it was identified as mucosal irritation, apparently due to hydroxylapatite cones that had previously been inserted to augment the residual alveolar ridge. Preservation and augmentation of an edentulous part of an alveolar ridge or of a fully edentulous alveolar ridge are both possible using alveolar implants and/or several surgical procedures. In the current case, such previous treatment was not known to have taken place. Consequently, the dentist was not able to provide treatment immediately. This case illustrates the need for general dental practitioners to keep an eye on their older patients and to provide all relevant information when the oral health care provision is taken over by another dentist.

A 4-Year Retrospective Radiographic Study of Marginal Bone Loss of 156 Titanium Implants Placed with Ultrasonic Site Preparation

This retrospective study evaluated implant survival rate (SR) and marginal bone loss around dental implants placed with ultrasonic implant site preparation. A total of 156 implants were placed in 28 totally and partially edentulous patients. Bone loss was measured on intraoral paralleling digital radiographs taken at the impression phase and after 4 years of loading. As 3 implants (1.92%) failed at the second surgery stage, the SR was 98.08% after 4 years. The mean marginal bone loss was 0.52 ± 0.33 mm (0.51 ± 0.35 mm mesially and 0.53 ± 0.35 mm distally), with comparable values for implants inserted into the maxilla (0.52 ± 0.32 mm) and the mandible (0.52 ± 0.35 mm).

Monolithic zirconia multiple-unit implant reconstructions on titanium bonding bases

The development of titanium bonding bases allows for the use of implant-supported monolithic reconstructions in a digital workflow. Different base configurations are available according to each clinical indication. In this case report, the selection of titanium bonding bases for crowns was considered for a multiple-unit fixed dental prosthesis (FDP).

6 mm vs 10 mm-long implants in the rehabilitation of posterior jaws: A 10-year follow-up of a randomised controlled trial

PURPOSE

The aim of this study was to compare survival and success rates of 6 mm-long and 10 mm-long implants in partially edentulous posterior areas.

MATERIALS AND METHODS

Twenty-four patients with a partially edentulous area were included in the study. Patients were randomly allocated according to a parallel group design to receive 6 mm or 10 mm-long implants. A total of 54 implants were placed (26 × 6 mm implants). Patients were followed for 10 years after prosthetic loading. Outcome measures were prosthesis and implant survival, marginal bone level changes and complications.

RESULTS

After 10 years, 17 patients (eight with 6 mm implants and nine with 10 mm implants) were available: three 6 mm and four 10 mm patients were lost to follow-up. One 6 mm implant failed during the healing period and its related prosthesis could not be placed. No implants were lost after loading. Nine patients in the 6 mm group registered a total of 15 complications: two mucositis, six decementations and seven chippings. Ten patients in the 10 mm group registered a total of 13 complications: five mucositis, two decementations and six chippings. Overall the difference for complications between the two groups was not statistically significant (P = 0.22; difference in proportion = -0.02; 95% CI: -0.31 to 0.27). Decementations in the 6 mm group were statistically significant higher than the 10 mm group (P = 0.04; difference in proportion = 0.39; 95% CI: 0.03 to 0.74). Marginal bone loss at 10 years was 0.84 and 0.37 mm with the 6 mm and 10 mm groups, respectively (difference between the two groups 0.49 mm; 95% CI -0.31; 1.29; not statistically significant: t test P = 0.22).

CONCLUSIONS

Rehabilitations supported by 6 mm or 10 mm-long implants showed similar clinical outcomes in terms of survival and success rates, although 6 mm implants had more decementations.

Maxillary Sinus Lift with Beta-Tricalcium Phosphate (β-TCP) in Edentulous Patients: A Nanotomographic and Raman Study

Sinus lift elevation restores bone mass at the maxilla in edentulate patients before the placement of dental implants. It consists of opening the lateral side of the sinus and grafting beta-tricalcium phosphate granules (β-TCP) under the olfactory membrane. Bone biopsies were obtained in five patients after 60 weeks. They were embedded undecalcified in poly(methyl methacrylate) (pMMA); blocks were analyzed by nanocomputed tomography (nanoCT); specific areas were studied by Raman microspectroscopy. Remnants of β-TCP were osseointegrated and covered with mineralized bone; osteoid tissue was also filling the inner porosity. Macrophages having engulfed numerous β-TCP grains were observed in marrow spaces. β-TCP was identified by nanoCT as osseointegrated particles and as granules in the cytoplasm of macrophages. Raman microspectroscopy permitted to compare the spectra of β-TCP and bone in different areas. The ratio of the ~820 cm^-1 band of pMMA (-CH₂ groups) on the ν1 phosphate band at 960 cm^-1 reflected tissue hydration because water was substituted by MMA during histological processing. In bone, the ratio of the ~960 cm^-1 phosphate to the amide 1 band and the ratio ν2 phosphate band by the 1240-1250 amide III band reflect the mineralization degree. Specific bands of β-TCP were found in osseointegrated β-TCP granules and in the grains phagocytized by the macrophages. The hydration degree was maximal for β-TCP phagocytized by macrophages. Raman microspectroscopy associated with nanoCT is a powerful tool in the analysis of the biomaterial degradation and osseointegration.

Subcrestal placement of dental implants with an internal conical connection of 0.5 mm versus 1.5 mm: Outcome of a multicentre randomised controlled trial 1 year after loading

PURPOSE

To evaluate whether there are some clinical benefits by placing single dental implants either 0.5 or 1.5 mm subcrestally in healed bone crests.

MATERIALS AND METHODS

Sixty partially edentulous patients requiring two single implant-supported crowns had both sites randomly allocated either to 0.5 mm or 1.5 mm subcrestal implant placement according to a split-mouth design at six centres. Implants were submerged in aesthetic areas or non-submerged in non-aesthetic areas for 3 months. Provisional acrylic crowns were delivered and were replaced after 2 months by definitive metal-ceramic crowns. Patients were followed to 1 year after loading. Outcome measures were: crown and implant failures; complications; aesthetics assessed using the pink esthetic score (PES); peri-implant marginal bone level changes; and patient preference, recorded by blinded assessors.

RESULTS

One patient dropped out. One patient lost both implants to infection at impression taking. Three complications affected three patients of the 0.5 mm group and two complications affected two patients of the 1.5 mm subcrestally placed implants. One patient had complications at both implants. There were no statistically significant differences for complications between group (difference of proportion = 0.02; 95% CI -0.06 to 0.09; P (McNemar test) = 1.000). At delivery of definitive crowns, 2 months after loading, the mean aesthetic score was 11.22 ± 1.91 and 11.12 ± 1.59 for the 0.5 and 1.5 mm group, respectively. At 1 year after loading, the mean aesthetic score was 12.09 ± 1.66 and 12.10 ± 1.52 for the 0.5 and 1.5 mm group, respectively. There were no statistically significant differences between the two groups at 2 months (P (paired t test) = 0.626) or at 1 year (P (paired t test) = 0.920). One year after loading, patients of the 0.5 mm lost on average 0.21 ± 0.51 mm and those of the 1.5 mm group 0.11 ± 0.36 mm, the difference being not statistically significant (difference = 0.10; 95% CI -0.01 to 0.20; P (paired t test) = 0.078). Patients did not prefer any depth of the implant placement over the other. There were no differences in outcomes between centres.

CONCLUSIONS

No statistical or clinical differences were noticed when placing implants 0.5 mm or 1.5 mm subcrestally, therefore clinicians can do as they prefer. Conflict-of-interest statement: Anthogyr (Sallanches, France), the manufacturer of the implants used in this investigation, partially funded this trial and donated the implants and the prosthetic components, however data belonged to the authors and by no means did the sponsor interfere with the conduct of the trial or the publication of its results.

The Shortened Dental Arch concept from the perspective of Swedish General Dental Practitioners: a qualitative study

The aim was to study the cognizance of and attitudes towards the Shortened Dental Arch (SDA) concept among Swedish General Dental Practitioners (GDPs) and the application of the SDA concept in their treatment planning using Qualitative Content Analysis. Eleven Swedish GDPs were purposively selected and all agreed to participate. In-depth semi-structured interviews were conducted and covered treatment considerations concerning two patient cases and the participants' reflections regarding pre-formulated statements about the SDA concept. Qualitative content analysis was used to analyze this data.The emerging theme was "the SDA concept is irrelevant" in the sense of the GDPs disregarding treatments providing dentitions with loss of posterior teeth. There was a strong reluctance to extract teeth, without consideration of the SDA concept, and a firmly patient-focused attitude towards the needs, age and financial situation of the patients. Within the limitations of this study, Swedish GDPs show little or no cognizance of the SDA concept and it does not seem to be applied in their treatment planning. The results show that the qualitative methodology can be beneficial for further understanding of cognizance and attitudes towards the SDA concept.

Accuracy of implant impressions for partially and completely edentulous patients: a systematic review

PURPOSE

To compare the accuracy of digital and conventional impression techniques for partially and completely edentulous patients and to determine the effect of different variables on the accuracy outcomes.

MATERIALS AND METHODS

An electronic and manual search was conducted to identify studies reporting on the accuracy of implant impressions. Pooled data were descriptively analyzed. Factors affecting the accuracy were identified, and their impact on accuracy outcomes was assessed.

RESULTS

The 76 studies that fulfilled the inclusion criteria featured 4 clinical studies and 72 in vitro studies. Studies were grouped according to edentulism; 41 reported on completely edentulous and 35 on partially edentulous patients. For completely edentulous patients, most in vitro studies and all three clinical studies demonstrated better accuracy with the splinted vs the nonsplinted technique (15 studies, splint; 1, nonsplint; 9, no difference). One clinical study and half of the in vitro studies reported better accuracy with the open-tray vs the closed-tray technique (10 studies, open-tray; 1, closed-tray; 10, no difference). For partially edentulous patients, one clinical study and most in vitro studies showed better accuracy with the splinted vs the nonsplinted technique (8 studies, splint; 2, nonsplint; 3, no difference). The majority of in vitro studies showed better accuracy with the open-tray vs the closed-tray technique (10 studies, open-tray; 1, closed-tray; 7, no difference), but the only clinical study reported no difference.

CONCLUSION

The splinted impression technique is more accurate for both partially and completely edentulous patients. The open-tray technique is more accurate than the closed-tray for completely edentulous patients, but for partially edentulous patients there seems to be no difference. The impression material (polyether or polyvinylsiloxane) has no effect on the accuracy. The implant angulation affects the accuracy of implant impressions, while there are insufficient studies for the effect of implant connection type. Further accuracy studies are needed regarding digital implant impressions.

Assessment of the consequences in premature loss of the temporary lower molars

The consequences of premature loss of temporary teeth are complex, both of functional and morphological order and the clinical presentation depends on multiple factors: the temporary tooth loss rate as compared with permanent tooth eruption sequence and the number and topography of teeth extracted, so the clinical form of edentulous, which can be frontal or lateral, symmetric or asymmetric, isolated or continuous.

A preliminary study on local administration of dexamethasone after tooth extraction--Better preservation of residual alveolar ridge?

BACKGROUND/AIM

It is important that the height of the edentulous alveolar ridge after tooth extraction remains at a reasonable acceptable level for as long as possible. The aim of this study was to report preliminary results of the clinical effect of local oral submucous administration of dexamethasone after tooth extractions in order to prepare alveolar supporting tissues for acceptance of removable dentures.

METHODS

In a total of 15 patients (11 partially and 4 completely edentulous) the quantity of 0.25 mL to 0.5 mL of dexamethasone was injected bucally and orally in the region of the tooth socket after complicated extractions.

RESULTS

Healing of extraction wounds was uneventful in all the patients, without pain or local inflammation.

CONCLUSION

Dexamethasone can be locally applied to oral tissues to prevent post-extraction inflammation and extensive resorption of the residual alveolar ridge. The obtained results are promising for patients undergoing classic prosthodontic rehabilitation soon after tooth extraction, demonstrating that there are no adverse effects after local oral corticosteroids administration.

Influence of crown-to-implant ratio, retention system, restorative material, and occlusal loading on stress concentrations in single short implants

PURPOSE

The aim of this study was to assess the contributions of some prosthetic parameters such as crown-to-implant (C/I) ratio, retention system, restorative material, and occlusal loading on stress concentrations within a single posterior crown supported by a short implant.

MATERIALS AND METHODS

Computer-aided design software was used to create 32 finite element models of an atrophic posterior partially edentulous mandible with a single external-hexagon implant (5 mm wide x 7 mm long) in the first molar region. Finite element analysis software with a convergence analysis of 5% to mesh refinement was used to evaluate the effects of C/I ratio (1:1; 1.5:1; 2:1, or 2.5:1), prosthetic retention system (cemented or screwed), and restorative material (metal-ceramic or all ceramic). The crowns were loaded with simulated normal or traumatic occlusal forces. The maximum principal stress (stressmax) for cortical and cancellous bone and von Mises stress (stressvM) for the implant and abutment screw were computed and analyzed. The percent contribution of each variable to the stress concentration was calculated from the sum of squares analysis.

RESULTS

Traumatic occlusion and a high C/I ratio increased stress concentrations. The C/I ratio was responsible for 11.45% of the total stress in the cortical bone, whereas occlusal loading contributed 70.92% to the total stress in the implant. The retention system contributed 0.91% of the total stress in the cortical bone. The restorative material was responsible for only 0.09% of the total stress in the cancellous bone.

CONCLUSION

Occlusal loading was the most important stress concentration factor in the finite element model of a single posterior crown supported by a short implant.

[A case of occlusal support loss in the molar region due to distal extension missing of the left of the upper and right of the lower jaws]

PATIENT

A 74-year-old woman visited our hospital with a chief complaint of masticatory dysfunction due to upper left molar denture breakage and poor retention of upper and lower dentures. The cause of the denture breakage was a lack of clearance, and that of denture instability was the unilateral design in the upper jaw, and breakage of the indirect retainer in the lower jaw. The treatment plan was set to securing the denture strength and bracing via a bilateral design.

DISCUSSION

Stability was improved by bilateral design. Ensuring clearance and subsequent place on the dentures may have secured the strength.

CONCLUSION

The ability of mastication was improved by the new dentures. Regarding the strength, no breakage of the dentures occurred during the follow-up period, indicating that prosthetic treatment was appropriate.

[Case report of cone crown telescopic denture for bilateral lower free end missing]

PATIENT

The patient was a 46-year-old woman who complained of masticatory dysfunction with bilateral lower free end missing. At first, she wanted to receive dental implants, but she was afraid of undergoing surgery for implant insertion. Therefore she had taken an immediate removable partial denture. However, she was not satisfied with this denture on her requirements of retention, stability, and aesthetics. Considering this situation, we applied her cone crown telescopic denture.

DISCUSSION

The new cone crown telescopic denture has an excellent prognosis for the long-term. This denture, which has a rigid support design with adequate diagnosis, was indispensable to obtain such a fine result.

CONCLUSION

It is suggested that the cone crown telescopic denture was the best selection for the prosthetic treatment of this patient. Repeated maintenance of the denture and regular examination of periodontal tissue will be necessary to keep the good prognosis.

Interventions for replacing missing teeth: antibiotics at dental implant placement to prevent complications

BACKGROUND

Some dental implant failures may be due to bacterial contamination at implant insertion. Infections around biomaterials are difficult to treat and almost all infected implants have to be removed. In general, antibiotic prophylaxis in surgery is only indicated for patients at risk of infectious endocarditis, for patients with reduced host-response, when surgery is performed in infected sites, in cases of extensive and prolonged surgical interventions and when large foreign materials are implanted. To minimize infections after dental implant placement various prophylactic systemic antibiotic regimens have been suggested. More recent protocols recommended short term prophylaxis, if antibiotics have to be used. With the administration of antibiotics adverse events may occur, ranging from diarrhoea to life-threatening allergic reactions. Another major concern associated with the widespread use of antibiotics is the selection of antibiotic-resistant bacteria. The use of prophylactic antibiotics in implant dentistry is controversial.

OBJECTIVES

To assess the beneficial or harmful effects of systemic prophylactic antibiotics at dental implant placement versus no antibiotic/placebo administration and, if antibiotics are of benefit, to find which type, dosage and duration is the most effective.

SEARCH STRATEGY

The Cochrane Oral Health Group's Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE were searched up to 9th January 2008. Several dental journals were handsearched. There were no language restrictions.

SELECTION CRITERIA

Randomised controlled clinical trials (RCTs) with a follow up of at least 3 months comparing the administration of various prophylactic antibiotic regimens versus no antibiotics to patients undergoing dental implant placement. Outcome measures were prosthesis failures, implant failures, postoperative infections and adverse events (gastrointestinal, hypersensitivity, etc.).

DATA COLLECTION AND ANALYSIS

Screening of eligible studies, assessment of the methodological quality of the trials and data extraction were conducted in duplicate and independently by two review authors. Results were expressed as random-effects models using risk ratios (RRs) for dichotomous outcomes with 95% confidence intervals (CIs). Heterogeneity was to be investigated including both clinical and methodological factors.

MAIN RESULTS

Two RCTs were identified: one comparing 2 g of preoperative amoxicillin versus placebo (316 patients) and the other comparing 2 g of preoperative amoxicillin plus 500 mg 4 times a day for 2 days versus no antibiotics (80 patients). The meta-analyses of the two trials showed a statistically significant higher number of patients experiencing implant failures in the group not receiving antibiotics: RR = 0.22 (95% CI 0.06 to 0.86). The number needed to treat (NNT) to prevent one patient having an implant failure is 25 (95% CI 13 to 100), based on a patient implant failure rate of 6% in patients not receiving antibiotics. The other outcomes were not statistically significant, and only two minor adverse events were recorded, one of which in the placebo group.

AUTHORS' CONCLUSIONS

There is some evidence suggesting that 2 g of amoxicillin given orally 1 hour preoperatively significantly reduce failures of dental implants placed in ordinary conditions. It remains unclear whether postoperative antibiotics are beneficial, and which is the most effective antibiotic. It might be recommendable to suggest the use of one dose of prophylactic antibiotics prior to dental implant placement.

[Clinical application and follow-up evaluation of attachments in partial edentulous jaw prosthodontics]

OBJECTIVE

To evaluate the outcomes of attachments prosthesis in patients with complicated intraoral situation.

METHODS

Thirty-eight patients provided with fixed-removable partial denture were followed up for 1 to 5 years. A total of 51 attachments restoration supported by 139 abutments were included.

RESULTS

Good retention and stability of the restoration were achieved; masticatory function and esthetic effects were recovered satisfactorily.

CONCLUSIONS

Fixed-removable partial denture is an effective method for patients with complicated intraoral situation.

An investigation of overeruption of posterior teeth with partial occlusal contact

The need and demand for replacement of missing posterior teeth may increase as the UK population is predicted to be at least partially dentate for life. Replacement with either fixed or removable prostheses may be indicated, and the tooth positional changes of adjacent or opposing teeth may require consideration. The objectives of this study are to: (1) Investigate the extent of overeruption associated with partially opposed posterior teeth; (2) Determine if overeruption is associated with tipping of the partially opposed tooth and examine the extent of tip. Ninety-one patients with either partially or completely unopposed posterior teeth were included in the study. For each group the extent of overeruption of the tooth was measured. Differences in the extent of overeruption and tipping were analysed. Correlations between the presence of partial tooth contact and the extent of overeruption and degree of tipping of the unopposed tooth were analysed. There was no significant difference in the extent of overeruption between the unopposed and partially opposed groups. The partially opposed teeth displayed a greater degree of tipping than the unopposed group. There was no significant correlation between the extent of overeruption and the degree of tipping, nor between the extent of overeruption and the presence of partial tooth contact. There was, a significant correlation between the degree of tooth tip and the presence of partial tooth contact. (1) Partial tooth contact does not appear to prevent or reduce overeruption; (2) Partially opposed teeth show an increased degree of tip relative to teeth with complete lack of occlusal contact. The findings suggest that partial tooth contact should not be relied on clinically to maintain vertical tooth position.

Incidence, types and clinical implications of a non-metrical variant--mylohyoid bridging in human mandibles

Mylohyoid bridging (MB) is a non-metrical variant of the human mandible. The incidence and types of MB were investigated in 264 mandibles (edentulous 116, semi-dentulous 90 and dentulous 58). No mandible showed a complete type of MB, although 19 (7.2%) mandibles had a partial type. These were classified into two subtypes: distal partial (DP; Type I) and proximal partial (PP; Type II), depending on their location over the mylohyoid groove. The MB was present unilaterally in 7.76% of edentulous mandibles: right side 5.17% (3.45% PP type and 1.72% DP type) and left side 2.59% (1.72% PP type and 0.86% DP type). Of the semi-dentulous mandibles 3.33% had DP type of MB, 1.11% on the right side and 2.22% on the left side, and of the dentulous mandibles 1.72% had DP type of MB on the right side. A total of 13 mandibles out of 264 (4.92%) had unilateral MB. No dentulous mandible had bilateral MB, but 3.45% of edentulous and 2.22% of semi-dentulous mandibles did have. In total, 6 mandibles out of 264 bones (2.27%) had bilateral MB. Of the bilateral incidences 1.72% of edentulous mandibles had a DP-DP combination and the remaining 1.72% had a PP-DP combination. However, both instances of bilateral MB in semi-dentulous mandibles were of PP-DP combination. The incidence or types of MB showed no statistically significant differences between the groups or sides (p > 0.5; chi(2) test). In conclusion, the complete type of MB is a rare occurrence. The incidence increases with age, as edentulous mandibles had a higher incidence of MB than the other two groups. Clinically, MB may compress the mylohyoid neurovascular bundle, leading to neurological or vascular disorders.

Root Surface Caries in Older Individuals from Sri Lanka

The aim of the present study was to assess the prevalence and factors associated with root surface caries in older individuals from Sri Lanka. A total of 600 urban subjects aged 60 years and above was selected using a two-stage cluster sampling combined with probability-proportionate-to-size technique. The data were collected by means of an interviewer-administered questionnaire and an oral examination. The mean number of teeth present was 13.4 +/- 8.7. The prevalence of root surface caries was 89.7%. The mean number of root surfaces with decay or fillings and the mean root caries index (RCI) per subject were 3.8 and 25.0%, respectively. In both arches, the molars were the most affected by root caries. A multiple logistic regression analysis showed that betel chewing (OR = 0.36; 95% CI 0.20, 0.65), being >80 years of age (OR = 0.24; CI 0.09, 0.57), number of retained teeth (OR = 0.88; CI 0.83, 0.93) and number of root surfaces with recession (OR = 1.03; CI 1.01, 1.07) were significantly associated with the presence of root surface caries. In conclusion, it was evident from the study that the prevalence of root surface caries was high in this group of older individuals. Chewing betel, age, number of retained teeth and the number of root surfaces with recession emerged as significant predictors of root caries.

Prosthetic implant treatment of the edentulous maxilla with overdenture

The literature concerning the success of prosthetic implant treatment with maxillary overdenture is reviewed, and variables affecting treatment from the implant and prosthetic standpoint are analysed. Guidelines for the fabrication of maxillary overimplants comparable to those for mandibular overimplants are still lacking, as are evidence-based prosthetic design concepts. Individual methods and techniques have been described, but evaluation standards for the outcome of maxillary prosthetic-implant treatment are lacking or individually interpreted. The biomechanics involved in the proposed system are described, together with the advantages of telescopic crowns for the retention of removable partial prosthesis supported by maxillary implants. The positive influence, in terms of long-term prognosis, of the perio-protective design of removable partial prostheses supported by maxillary overimplants is also discussed. The proposed system not only provides stability, support and retention for removable partial prostheses supported by maxillary implants, but also enables implant survival rates to be improved, both for biomechanical reasons and due to improved oral hygiene. The simplification of fabrication procedures, repair, rebasing and re-operating also reduce the cost of follow-up and improve the cost/benefit ratio. However, additional studies are needed to clarify the number and most appropriate distribution of implants, as well as the most favourable prosthetic designs for maxillary overimplants.

Prevalence of temporomandibular disorder signs in patients with complete versus partial dentures

OBJECTIVES

To determine the prevalence of signs of a temporomandibular disorder (TMD) in completely edentulous patients wearing upper and lower complete dentures (CD) and to compare this to the prevalence of signs in partially edentulous patients wearing upper and lower clasp-retained acrylic removable partial dentures (RPD).

MATERIALS AND METHODS

A questionnaire and a clinical examination were used to assess 200 patients. One hundred of these were complete denture wearers being treated for the provision of replacement CD. The other 100 patients were partially edentulous patients, who had RPD replacing upper and lower partially missing teeth and their supporting structures.

RESULTS

It was shown that there was a statistically significant difference between the two groups regarding the presence of temporomandibular signs. Partially edentulous patients wearing upper and lower RPD had a significantly higher prevalence of TMD signs than edentulous patients wearing CD (36% compared to 17%). They also exhibited significantly (P<0.04) more signs of joint tenderness (18%) on clinical examination compared to (5%) only in the CD-wearing patients. Tenderness upon palpation in the periauricular region was the most common site reported in both groups.

CONCLUSIONS

The partially edentulous patients (wearing RPD) exhibited more TMD signs when compared with the CD-wearing patients. Significantly, more partially edentulous patients had joint tenderness (P<0.04) than did CD-wearing patients. The masseter muscle most commonly demonstrated muscle tenderness.

A study of the proximity of the Broadrick ideal occlusal curve to the existing occlusal curve in dentate patients

Increasingly, clinicians are called upon to restore dentitions, which have become mutilated because of tooth loss, wear, trauma and disease. In many cases, restoration of the occlusal plane may be required. A simple tool, which provides the laboratory technician with an approximation of the patient's original occlusal curve may be useful. The purpose of this study is to determine the accuracy of the occlusal curve designed using the Broadrick flag. A total of 100 patients with intact dental arches were examined, and deviations from the Broadrick curve were measured on scanned study models using a software package. Simple descriptive statistics were used to investigate the data, and intra-examiner reliability was examined using a Bland Altman plot. The results demonstrated little deviation from the Broadrick curve in natural adult dentitions, mean deviation 0.1262 mm, 95% confidence interval -0.32 to 0.2844. Good intra-examiner reliability was achieved. It can be concluded that the Broadrick flag method may be of use in determining an appropriate occlusal curve for dentate individuals with deranged occlusal planes.

Clinical quality of removable dentures provided by dentists, denturists and laboratory technicians

The aim of this study was to evaluate the clinical quality of removable dentures of elderly Finnish men, which had been prepared either by dentists, denturists or dental laboratory technicians. The participants comprised 242 denture-wearing subjects, with 231 maxillary and 177 mandibular removable dentures which had been prepared either by dentists, denturists or dental laboratory technicians. Clinical examinations were carried out without the examining dentist knowing who had provided the dentures. Complete dentures which had been illegally provided by laboratory technicians had significantly poorer retention and fitted less well in tuber and alveolar areas than those provided by either dentists or denturists. Complete maxillary dentures which had been provided illegally by laboratory technicians had significantly (P < 0.01) higher occurrence (90%) of some unacceptable characteristics than those (43%) provided by dentists or denturists. The difference between complete mandibular dentures was also obvious, 86% versus 59%, although statistically non-significant. Of those partial maxillary dentures provided by dentists 53% had some unacceptable characteristics, compared with 80% of those illegally provided by denturists or laboratory technicians (NS). In the case of partial mandibular dentures, 36% of those provided by dentists and 32% of those by denturists or laboratory technicians had some unacceptable characteristic (NS). Illegal provision of removable dentures seemed to be related to decreased clinical quality.

Stability of implants and natural teeth as determined by the Periotest over 60 months of function

Various methods for evaluating tooth mobility have been developed throughout the years, but their acceptance has been limited because of the subjectivity associated with their use. In recent years, the Periotest has been studied and used to evaluate the mobility of natural teeth and is claimed to b e potentially reliable in assessing the stability of the implant-bone interface. Few clinical implant studies have used natural teeth as controls to monitor changes in mobility associated with dental implants. The Dental Implant Clinical Research Group initiated a long-term clinical study in 1991 to assess the influence of design, application, and site of placement on clinical success and crestal bone height. As part of the study, Periotest values (PTVs) were recorded for 2,623 of the 2,998 implants placed and uncovered. For the statistical analysis, 2,623 implants were tested at second-stage surgery, with the number of implants tested varying at each follow-up visit. Data were collected from investigators at 32 study centers for periods ranging up to 60 months. A total of 975 natural teeth from 409 partially edentulous study subjects served as controls. FPVs on natural teeth and implants were combined, and the overall average Periotest values (OA-PTVs) were compared with values for individual subjects. The effect of implant and natural tooth locations on mobility were evaluated and compared with each other. The combined OA-PTV for all natural teeth was +1.8 and the OA-PTV for all implants was -3.4 PTVs. Compared with those in the maxillae, mandibular teeth and implants were found to be more stable Implants were found to be significantly more stable as compared with natural teeth. The recorded variations in PTVs for natural teeth and implants over the entire evaluation period were not found to be significantly different. This study developed the following conclusions: (1) implants were found to be significantly less mobile as compared with natural teeth for individual subjects; (2) the PTVs for natural teeth and implants did not exhibit significant variation over the evaluation period; (3) the Periotest can provide reproducible assessment of stability in a long-term clinical study; and (4) changes in PTVs may be helpful in evaluating improvement or degradation of the implant-bone complex.

[Oral care reduces pneumonia of elderly patients in nursing homes, irrespective of dentate or edentate status]

Aspiration of oral secretions and their bacteria, especially gram-negative bacilli, is increasingly being recognized as an important factor in pneumonia. We investigated whether oral care reduces the frequency of pneumonia in the institutionalized elderly. Nurses or caregivers cleaned patients' teeth with toothbrushes after each meal, and scrubbed the oropharynx with an applicator with povidone iodine (1%) every day. Dentists or dental hygienists gave professional care once a week. During follow up, pneumonia decreased significantly in patients with oral care. Oral care was of benefit for both edentate as well as dentate subjects, although periodontal diseases might cause pneumonia. We suggest that oral care may be useful in preventing pneumonia in institutionalized elderly, irrespective of dentate or edentate status.

[Prosthodontic treatment of missing molars (distal edentulous state class 1B); practice in Hungary based on mass screening]

Between the years of 1985 and 1989 we examined 9991 people. From the examined patients those people were selected, who lost their molars on one or both side, but they had no greater continuous edentate area in their dental arch than four teeth. The recorded data were evaluated separately by arches. 486 upper and 1568 lower arches filled the requirements of us. Patients wore in the upper jaw in 216 cases (46%) fixed prostheses with posterior cantilever pontic, in 26 cases (5%) combined prostheses (fixed + removable partial denture), in 18 cases (4%) removable partial dentures. 208 (45%) cases were untreated. In the lower arch in 417 cases (27%) fixed prostheses with a posterior cantilever pontic, in 97 cases (6%) combined prostheses (fixed + removable partial denture), in 57 cases (3%) removable partial dentures were constructed. 997 cases were (63%) were untreated. The results of this study indicate, that the treatment of distal edenate arches in the everyday practice is also verifying our prosthetic planning guidelines.

[Distribution of the position of the last remaining tooth in otherwise edentulous mouth, based on mass screening]

The authors examined the frequency of the last remaining tooth's positions in both arches and they found the canine in the lower arch in 63% and the second molar in 13% of the second molar. In single remaining tooth situations the rate of wearing denture is 73%. The cariological status of these teeth is negligible in relation to the bad periodontal health conditions, which are not influenced essentially by crowns or wearing dentures.

Impression technique for arches requiring both implant and natural tooth restorations

Implant impression copings reduce access to prepared teeth during the impression-making process. If the impression copings and teeth are in close proximity, it may be difficult to extrude impression material circumferentially around the margins of the tooth preparations. A technique is described that allows the impressions of the prepared teeth to be made without the implant impression copings interfering. The advantages and disadvantages of the technique are discussed.

[Five-year evaluation of implants in the resorbed maxilla]

The survival of implants placed in the resorbed maxillae was investigated. Both edentulous and partially edentulous patients were evaluated including those who underwent 'sinus lift' procedures. The group of patients with a sinus floor augmentation showed a five-year cumulative survival rate varying between 100% for fixed bridges on implants in the partially edentulous maxillae and 75.6% for implants under overdentures placed in severely resorbed edentulous maxillae. It is concluded that placement of implants in the augmented sinus-floor is justified, if the patient is well informed. The procedure can provide a good solution for the prosthetic problems of patients with a resorbed maxilla.

A retrospective study of the maintenance requirements associated with implant stabilised mandibular overdentures

The maintenance requirements of a group of 58 patients, treated with the IMZ osseointegrated implant system and mandibular overdentures were investigated. Prostheses were retained by either bar and clip or separate stud attachments. The patients were followed up regularly for periods of between one and six years. The median number of maintenance procedures required per patient per year varied between 1-5. Detailed examination of the data revealed that a wide range of maintenance procedures was required, including replacement prostheses in 46% of cases. There were some differences related to the retentive elements used for the prostheses.