Polymer-infiltrated ceramic CAD/CAM inlays and partial coverage restorations: 3-year results of a prospective clinical study over 5 years.

OBJECTIVE: The aim of this prospective clinical 5-year study was to evaluate the long-term behavior of monolithic computer-aided design and computer-aided manufacturing (CAD/CAM)-fabricated minimally invasive polymer-infiltrated ceramic network (PICN) inlays and partial coverage restorations (PCR). MATERIAL AND METHODS: Posterior teeth of 47 patients were restored with 103 restorations (45 inlays, 58 PCRs). After defect-oriented preparations, monolithic PICN restorations of VITA Enamic were fabricated with a CAD/CAM system (inEoS blue/CEREC inLab MCXL) and adhesively bonded (Variolink II). Clinical reevaluations were so far performed at baseline and 6, 12, 24, and 36 months after insertion according to modified United States Public Health Service (USPHS) criteria. Absolute failures were demonstrated by Kaplan-Meier survival rate and relative failures by Kaplan-Meier success rate. A logistic regression model was adjusted for modified USPHS criteria to investigate time and restoration effects (p < 0.05). RESULTS: After an observation time of 3 years, survival rates were 97.4% for inlays and 95.6% for PCRs. Three restorations had to be replaced due to clinically unacceptable fractures. Secondary caries and debonding were not observed. The 3-year Kaplan-Meier success rate was 84.8% for inlays and 82.4% for PCRs. The decrease in marginal adaption (p = 0.0005), increase in marginal discoloration (p < 0.0001), and surface roughness (p = 0.0005) over time were significant. Color match and anatomic form were excellent. No significant differences were found between both types of restorations for survival (p = 0.716) and success rate (p = 0.431). CONCLUSIONS: Minimally invasive PICN restorations showed a favorable clinical performance over an observation period of 36 months. However, clinical long-term data have to be awaited. CLINICAL RELEVANCE: PICN restorations are a suitable treatment option for posterior inlays and PCRs.

Five-year results of a prospective randomised controlled clinical trial of posterior computer-aided design-computer-aided manufacturing ZrSiO4 -ceramic crowns.

The aim of this prospective randomised controlled clinical trial was to evaluate the clinical outcome of shrinkage-free ZrSiO4 -ceramic full-coverage crowns on premolars and molars in comparison with conventional gold crowns over a 5-year period. Two hundred and twenty-three patients were included and randomly divided into two treatment groups. One hundred and twenty-three patients were restored with 123 ZrSiO4 -ceramic crowns, and 100 patients received 100 gold crowns, which served as the control. All crowns were conventionally cemented with glass-ionomer cement. After an observation period of 6, 12, 24, 36, 48 and 60 months, the survival probability (Kaplan-Meier) for the shrinkage-free ZrSiO4 -ceramic crowns was 98·3%, 92·0%, 84·7%, 79% and 73·2% and for the gold crowns, 99%, 97·9%, 95·7%, 94·6% and 92·3%, respectively. The difference between the test and control group was statistically significant (P = 0·0027). The gold crowns showed a better marginal integrity with less marginal discoloration than the ceramic crowns. The most common failure in the ceramic crown group was fracture of the crown. The 60-month results of this prospective randomised controlled clinical trial suggest that the use of these shrinkage-free ZrSiO4 -ceramic crowns in posterior tooth restorations cannot be recommended.

Effect of veneering technique on the fracture resistance of zirconia fixed dental prostheses.

To compare the fracture resistance of zirconia 3-unit posterior fixed dental prostheses (FDPs) frameworks veneered with different veneering materials and techniques before and after artificial ageing. Forty-eight zirconia 3-unit FDPs, representing a missing first molar, were adhesively cemented on human teeth. The zirconia frameworks were randomly distributed according to the veneering materials and techniques into three groups, each containing 16 samples: group LV (layering technique/Vintage ZR), group LZ (layering technique/ZIROX) and group PP (CAD/CAM and press-over techniques/PressXZr). Half of each group was artificially aged through dynamic loading and thermocycling to simulate 5 years of clinical service. Afterwards, all specimens were tested for fracture resistance using compressive load. An analysis of variance (anova) was used to assess the effect of veneering ceramic and artificial ageing on fracture resistance (P < 0·05). Except for one minor cohesive chipping in group LV1, all specimens survived artificial ageing. The mean fracture resistance values (in Newton) of different non-aged (± s.d.)/aged (± s.d.) groups were as follows: LV0 2034 (± 401)/LV1 1625 (± 291); LZ0 2373 (± 718)/LZ1 1769 (± 136); and PP0 1959 (± 453)/PP1 1897 (± 329). Artificial ageing significantly reduced the fracture resistance in groups veneered with the layering technique (P < 0·05), whereas no significant effect was found in specimens veneered with the CAD/CAM and press-over techniques. All tested systems have the potential to withstand occlusal forces applied in the posterior region. The combination of the CAD/CAM and press-over techniques for the veneering process improved the overall stability after artificial ageing, relative to the layering technique.

Success rates of prosthetic restorations on endodontically treated teeth; a systematic review after 6 years.

The aims of this systematic review were to investigate the success rates of prosthetic restorations on endodontically treated teeth and their manner of failure. PubMed and hand literature searches were conducted on studies published until June 2012. Only clinical studies on human subjects referring to the success rates of prosthetic restorations on endodontically treated teeth with a follow-up period of at least 6 years were reviewed. A total of four studies were identified. Meta-analysis showed the success rate to be 92% (CI 82-98%) for single crowns on endodontically treated teeth and 79% (72-86%) for fixed dental prostheses. Only one study reported on removable dental prostheses with a success rate of 66%. Single crowns on teeth restored without posts demonstrated a success rate of 94% (CI 84-99%), whereas where posts were placed, the success rate was lower (92% CI 82-98%). Single crowns over cast post-and-cores and prefabricated posts showed success rates of 93% (CI 82-99%) and 94% (CI 90-97%), respectively; both differences were not statistically significant (significance level of 5%). The most common reason for failure was post-debonding. Single crowns seem to be the best treatment modality for endodontically treated teeth. However, due to the low number of studies included and their design, the results of this systematic review should be interpreted with caution. Further clinical studies are needed to provide high-quality evidence on the topic.

Prognosis of immediately loaded implants and their restorations: a systematic literature review.

Immediate loading of oral implants has become popular because of the increasing demands of a shortened treatment time. This literature review evaluates the prognosis of immediately loaded implants and their restorations with immediate or delayed implant placement. Special attention was given to the impact of type of jaw, bone quality, implant length, time of implant placement and type of restoration. An electronic (PubMed) and a manual search in relevant journals were conducted until February 2012. Only publications in English, in peer-reviewed journals, were considered. Nine studies met the inclusion criteria: five studies dealt with fixed restorations, two studies with removable rehabilitation of edentulous jaws and two studies dealt with partially edentulous patients. Implant survival rates ranged from 95·8% to 100%, implant success rates in the treatment for the mandible from 79% to 100% and restoration survival rates for both jaws from 96·4% to 100%. Within the limits of this review, appropriate patient selection, primary implant stability, splinting of implants and the expertise of surgeons seem to be important for the prognosis of immediately loaded implants and their restorations. Good bone quality and use of long implants appear to play a role. However, careful interpretation is required because conclusions are based on articles with low level of evidence. While immediate loading of oral implants in the mandible shows encouraging and predictable results, further multicenter randomised controlled clinical trials with sufficient statistical power are needed to examine (i) the outcome of immediately loaded implants in the maxilla and (ii) the outcome of immediate loading of immediately placed implants.

Prognosis of implants and fixed restorations after lateral sinus elevation: a literature review.

Aim of this review was to investigate the prognosis of implants inserted in augmented sinuses and fixed restorations supported by these implants. Special attention was given to the impact of grafting material, time of implant placement, residual bone height and type of fixed restoration. An electronic search in PubMed, the German database medpilot and the Cochrane Library was executed followed by supplementary manual search in relevant journals. The search was limited to human studies published up to November 2010. Only publications in English and German, in peer-reviewed journals, were considered. After the initial search and application of selection criteria on titles and abstracts, a full-text analysis of 67 articles was performed, out of which six prospective and three retrospective studies were finally included in the review. The heterogeneous properties of the identified articles did not allow systematic analysis of the data. Success rates of implants were between 96·3% and 100%, survival rates were between 75% and 100%, and survival rates of single crowns, splinted crowns and fixed partial dentures ranged between 96·4% and 100% after a follow-up of 12-101 months. Within the limits of this review, the prognosis of implants and fixed restorations seemed not to be influenced by the type of restorations, graft material, residual bone height and time of implant placement. However, conclusions of this review are based on studies with low level of evidence; therefore, careful interpretation is required. Multicentre randomised controlled clinical trials with sufficient statistical power concentrating on few factors are needed to reach sound conclusions.

The dental patient on oral anticoagulant medication: a literature review.

Specific diseases and medications may considerably influence the delivery of oral care and the course of dental therapy. The purpose of this literature review is to examine the relationship between oral anticoagulant medication and dental treatment. Electronic and manual searches were conducted for clinical studies in the English literature for the years 1988-2010. The review process provided a total of 110 pertinent literature references, out of which 38 studies dealt with oral anticoagulants and dental treatment. Different treatment strategies relative to dental periprocedural anticoagulation regimens have been identified, and their accompanying thromboembolic and bleeding risks are being presented and discussed. Regarding to what extent a safe and successful dental treatment in patients on anticoagulant medication is feasible, the level of evidence is lacking. Until high-level data are provided, an individualised treatment approach after consultation with the physician of the patient is highly recommended.

Prosthetic outcome of cement-retained implant-supported fixed dental restorations: a systematic review.

The aim of the article is to assess the current literature in terms of the prosthetic outcome of cement-retained implant-supported fixed restorations, as well as to determine the type of cement that can be recommended for clinical application. A review of the literature published up to May 2010 was conducted to identify clinical studies about cement-retained implant-supported fixed restorations. The search strategy applied was a combination of MeSH terms and free text words, including the following keywords: implants, implant-supported fixed dental prostheses (FDPs), bridges, implant-supported single crowns (SCs), cement-retained, cement fixation, cement, cementation, cement failure, retention, and loss of retention, technical complications, mechanical complications, prosthetic complication, retrievability and maintenance. Thirty-two studies met the inclusion criteria. The studies were divided into two categories: 15 short-term clinical studies with an observation period of less than 5 years, and 17 long-term clinical studies with an observation period of 5 years and more. The most common technical complications of cement-retained implant-supported fixed restorations were loss of retention, chipping and abutment screw loosening. The results of the current review revealed no guidelines about cement or cementation procedures. It may be stated that despite the questionable retrievability of cement-retained implant-supported fixed restorations, this treatment modality is a reliable and effective option, especially for implant-supported SCs and short-span FDPs. The literature does not provide accurate information about the clinical outcome of cement-retained implant-supported fixed restorations nor about the ideal type of cement that facilitates stability and maintains retrievability. Standardised randomised clinical trials will provide valuable information to this issue.

Results of a prospective randomized controlled trial of posterior ZrSiO(4)-ceramic crowns.

The aim of this randomized controlled clinical trial was to evaluate over a 5-year period, the clinical outcome of shrinkage-free ZrSiO(4)-ceramic (KaVo Everest HPC) full coverage crowns on posterior teeth in comparison with conventional gold crowns that served as the control. This study reports results of a 5-year study protocol up to 24 months. Patients totalling 224 were randomly divided into two treatment groups. Of these, 123 patients were restored with 123 Everest HPC crowns, fabricated by the Kavo Everest computer-aided manufacturing (CAM) procedure and 101 patients received 101 gold crowns, but two were excluded from analysis. All crowns were conventionally cemented with glass-ionomer cement. After an observation period of 6, 12 and 24 months, the prospective survival rates (Kaplan-Meier) for the KaVo Everest HPC crowns were 97.9%, 95.1% and 89.8% and for the gold crowns 100%, 94.8% and 92.7%, respectively. There were no significant differences between the two groups (P = 0.2). The 1-year failure rates were 4.9% for the KaVo Everest HPC crowns and 5.2% for the gold crowns. The 1-year cumulative risks for loss of vitality, secondary caries, fractures, loss of crown and extraction of abutment of the analyzed abutments (88) were 8.9%, 0%, 0%, 1.1% and 1.1%, respectively, for the gold crowns and 2.8%, 0%, 4.7%, 0% and 0.9%, respectively, for the ceramic crowns (107 analyzed abutments). No perfect marginal fit was shown by 49.5% of the evaluated ceramic crowns and 26.1% of the gold crowns. Only 1.9% of the KaVo Everest HPC crowns had a marginal crevice. In conclusion, Everest HPC crowns with an adequate occlusal tooth reduction of >1.5 mm are suitable for posterior restorations, but the marginal fit shows a potential for improvement.

Dental occlusion: a critical reflection on past, present and future concepts.

For nearly a century, the diversity of concepts about 'normal' and 'ideal' dental occlusal relationships has led to confusion in trying to describe the occlusion of any individual patient. In addition, a similar controversy arises when trying to formulate treatment plans for patients who need extensive dental restorations or orthodontic treatment. And finally, the application of occlusal concepts to patients with temporomandibular pain and dysfunction has created a third area of debate. Over the past few decades, however, an appreciable part of the tenacious dogmatic heritage of this topic has been challenged. As a result, the acceptance of morphological and functional variability of the stomatognathic system has gained increasing support, and this change has important consequences for modern dental practice. In this article, the past, present and future of the subject of occlusion will be considered.

Material characteristics of a novel shrinkage-free ZrSiO(4) ceramic for the fabrication of posterior crowns.

OBJECTIVE: To confirm the clinical applicability of a novel ZrSiO(4) (zircon) based shrinkage-free ceramic material, the flexural strength, fracture toughness and chemical solubility were tested. In addition, the fracture load of full crowns made from this material was tested after cyclic thermomechanical loading. METHODS: Flexural strength of 12 specimens was measured using a biaxial bending test. Fracture toughness was measured using 10 slotted box shaped specimens. The specimens were fractured using a universal testing machine; fracture loads were recorded. A chemical solubility test was performed in accordance with ISO norm 6872. Additionally, 32 ZrSiO(4) all-ceramic crowns were fabricated on extracted caries-free human molars. Sixteen Empress 2 and 16 PFM crowns served as a reference control. After artificial aging of 1.2 million cycles in the chewing simulator, the survival rate of the crowns was determined. The fracture load of all surviving specimens was obtained by loading the crowns until fracture in a universal testing machine. RESULTS: A flexural strength of 328MPa was found. The fracture toughness of the ZrSiO(4) ceramic was 5.16MPam(0.5). The chemical solubility amounted to 7.2microg/cm(2). All specimens survived the chewing simulation (survival rate: 100%); no crowns had to be re-cemented. A mean fracture strength of 1790N was found for Everest HPC for Empress 2 crowns, 1715N for Empress 2 crowns and 2416N for PFM crowns. Fracture loads of PFM crowns were significantly higher than for Empress 2 crowns (P=0.032) as well as ZrSiO(4)-crowns (P=0.007). There was no significant difference between ZrSiO(4)-crowns and Empress 2 crowns (P=0.743). SIGNIFICANCE: At the present stage, Everest HPC can be recommended for the fabrication of single crowns as an alternative to conventional PFM and other all-ceramic crowns, because its fracture strength exceeds average masticatory forces in the posterior region.

Marginal adaptation of different types of all-ceramic partial coverage restorations after exposure to an artificial mouth.

OBJECTIVES: To determine the influence of the preparation design and the dimensions of all-ceramic partial coverage restorations (PCR) on the marginal accuracy before and after masticatory simulation. METHODS: In this in vitro study 80 extracted human maxillary molars were restored with MOD inlay restorations and four different modified PCR restorations using a new press ceramic IPS e.max Press (IPS e.max Press VP 1989). The teeth were divided into five groups of 16 specimens each and prepared as follows: Group A received an MOD inlay preparation and Group B, C, D and E received modified PCR. The restorations were adhesively luted and exposed to a mastication simulator. The discrepancies of the marginal fit were examined on epoxy replicas before and after luting as well as after masticatory simulation at 200x magnification. RESULTS: The mean (geometrical) [95% confidence limits] marginal gap decreased from Group A to E before cementation (A-83[77-90]microm, B-68[65-70]microm, C-59[55-64]microm, D-56[52-61]microm, E-50[45-55]microm). Group A had significantly higher marginal gap values than group B (p = 0.017) and the other groups (p<0.0001). After cementation the marginal accuracy was recorded as following: A-103[93-114]microm, B-101[94-108]microm, C-93[89-98]microm, D-102[98-105]microm and E-99[96-102]microm. Cementation increased the marginal gap in groups B-E significantly (p<0.00001), not significantly in group A (p = 0.059). Artificial ageing (A-116[106-127]microm, B-114[109-120]microm, C-106[103-110]microm, D-109[100-118]microm and E-109[105-112]microm) led to further significant decrease of marginal accuracy in Group B (p = 0.029) and C (p = 0.026) only. After cementation and masticatory simulation of the ceramic restorations, the marginal gap values of Groups A, B, C, D and E did not significantly differ from each other (p = 1.00). CONCLUSIONS: The result of this in vitro study showed that IPS e.max Press can be used to fabricate all-ceramic inlays and PCR which meet the requirements in terms of a clinically acceptable marginal gap, irrespective of the preparation design used. However, the preparation design and dimensions of the restorations appeared to affect the initial marginal fit and flowing off of luting material during the cementation process. The factors responsible for these findings require further substantiation.

Comparison of tricalcium phosphate and frozen allogenic bone implants in man.

As part of their treatment, eight patients with 47 infrabony pockets and horizontal bone defects had 29 tricalcium phosphate and 18 frozen allogenic bone implants placed. One year after surgery the sites were reentered. At the tricalcium phosphate implant sites the average amount of bone apposition was 1.2 mm and pocket depth induction 1.8 mm; 38% of the pockets remained deeper than 3.0 mm. At the allogenic bone sites the average amount of bone apposition was 1.5 mm and pocket depth reduction was 2.0 mm; 22% of the pockets remained deeper than 3.0 mm. The implant materials were well tolerated and there were no complications during the period of the study. Though storage and handling of tricalcium phosphate was simpler, use of allogenic bone led to greater bone apposition and reduction in pocket depth.

Immunohistochemical distribution of extracellular matrix proteins as a diagnostic parameter in healthy and diseased gingiva.

This study showed histopathological findings of the extracellular matrix in healthy, inflamed, and hyperplastic human gingiva with immunohistochemical techniques. The distribution of collagen types V and VI, as well as of glycoprotein fibronectin, shows that they are extracellular matrix structural components which differentiate the tissue pathology. The orientation of the collagen fibers, the intensity of the fluorescent staining, the thickness of the fibrillar component, and the topographical localization of the connective tissue proteins are important parameters for tissue morphology. Therefore, bacterial deposits and the pharmacodynamic properties of drugs associated with gingival hyperplasia lead to an alteration of the matrix compared to the healthy tissues. This may be important in the tissue pathology in cases when the medical history of the patient is not known, as well as in forensic medicine.

Changes in peri-implant tissues subjected to orthodontic forces and ligature breakdown in monkeys.

The aims of this investigation were to histologically evaluate in monkeys the effect of a repetitive mechanical trauma alone on the peri-implant tissues, and the effect of a repetitive mechanical trauma in combination with ligature-induced peri-implantitis on the peri-implant tissues. The study used 5 male cynomolgus monkeys. Prior to the start of the study, all premolars and the first and second molars in the mandible were extracted. After a healing period of 12 weeks, following tooth extraction, split/full thickness flaps were elevated on both sides of the mandible in order to expose the bony ridge. Four implants, of 3.75 mm in diameter and 7 mm in length, were then inserted on each side and the flaps were readapted and sutured in place. Following a healing period of 16 weeks, the second stage procedure was performed, impressions were taken, and custom-made crowns using a non-precious metal alloy were fabricated and inserted on all implants 4 weeks after abutment connection. At the same time peri-implantitis was induced on one side of the mandible by placing plaque-retentive ligatures around the implants. On the other side, an oral hygiene program consisting of thrice weekly brushing with a toothbrush and flour of pumice mixed with 2% chlorhexidine was initiated. Four months later, a repetitive mechanical trauma was initiated on implants 1 and 2 on both sides in the mandible. Consequently, a split mouth design was obtained: 1) test 1=ligature-induced peri-implantitis alone (LPNO); 2) test 2=ligature-induced peri-implantitits with a repetitive mechanical trauma (LPMT); 3) test 3=healthy peri-implant tissues with a repetitive mechanical trauma (MT); and 4) control (NO)=healthy peri-implant tissues with no repetitive mechanical trauma. Following 16 weeks of repetitive mechanical trauma the animals were sacrificed. Histologic observations and computed-assisted histometric and histomorphometric analyses were performed to determine the amount of peri-implant bone loss and the percentage of direct mineralized bone-to-implant contact around each endosseous oral implant. Histologically, all implants yielded osseointegration at the light microscopic level. There was a significant difference regarding the mean direct mineralized bone-to-implant contact length as a fraction of the total implant length between the healthy (i.e., MT and NO) and diseased sites (i.e., LPNO and LPMT) (P < 0.05). When comparing the percent of direct mineralized bone-to-implant contact for the 2 best threads of each implant and group, no significant difference (P=0.675) could be detected. Under the conditions of this study, the repetitive mechanical trauma showed no histologic effect on the peri-implant bone loss neither in healthy nor in diseased implant sites. The effects of excessive loading on osseointegration are presently not clearly understood. The key problem seems to be the determination when loading on implants exceeds the physiological range of bone adaptation which may then cause implant failure. Further research to elucidate this problem is essential.

Inflamed human periodontal versus peri-implant gingival tissues: an immunohistochemical differentiation of the extracellular matrix.

Inflamed human periodontal and peri-implant (ITI Bonefit) gingival tissues were studied immunohistochemically to evaluate the possible presence of structural differences in the extracellular matrix protein localization. Collagen types I, III, IV, V, VI, and VII and fibronectin showed a similar distribution in these tissues. Data show that morphologic structural differences between these inflamed tissues are not present. According to these findings, the connective tissue response of inflamed peri-implant as well as periodontal gingival tissues should be similar during treatment when the inflammation is localized only in the soft tissue level.

Treatment of ligature-induced peri-implantitis using guided tissue regeneration: a clinical and histologic study in the beagle dog.

This study evaluated the treatment of ligature-induced peri-implantitis using guided tissue regeneration (GTR) around submerged and nonsubmerged implants in beagle dogs. Two titanium implants were placed bilaterally in the premolar regions of the mandible in each of 10 beagle dogs. Cotton floss ligatures were placed around the implant necks and no oral hygiene procedures were performed for 5 months. Periodontal surgery was performed, and in five dogs (submerged group) the abutments were removed and an e-PTFE barrier was placed to cover the test implants and their adjacent osseous defects, while the control implants received no barriers. In the other five dogs (nonsubmerged group), flap surgery was performed without removing the abutments. In the test sites, an e-PTFE barrier was placed around the abutment and adjacent defects, while on the control sites no barrier was placed. Nondecalcified specimens were prepared using standard histologic methods and analyzed. No differences were found between any of the clinical parameters in both the control and experimental sites from the submerged and nonsubmerged groups. Histologic and histomorphometric analyses also revealed no significant differences between groups with regard to new bone formation. In the experimental (GTR) groups, however, the amount of regenerated connective tissue was significantly greater than on the control groups. Under the conditions of this study, the treatment of peri-implantitis using GTR did not enhance clinical parameters or bone formation around "diseased" implants.

Health human periodontal versus peri-implant gingival tissues: an immunohistochemical differentiation of the extracellular matrix.

Healthy human periodontal and peri-implant (ITI Bonefit) keratinized gingival tissues were studied immunohistochemically to evaluate the possible presence of structural differences in the extracellular matrix protein localization. Collagen types I, III, IV, and VII and fibronectin showed similar distribution in these tissues. Compared to the periodontal tissues, collagen type V was localized in higher amounts in the lamina propria of the peri-implant gingival tissues. Collagen type VI stained the periodontal tissues as a delicate microfibrillar network contrasting to the not well-stained peri-implant gingival tissues. The data show that structural differences between these tissues are present. The structural differences may be responsible for the defense of peri-implant keratinized gingival connective tissues to bacterial penetration, because of the high amount of the collagen type V component, which is responsible for the higher collagenase stability.

Computerized axiographic evaluation of condylar movements in cases with fractures of the condylar process: a follow up over 19 years.

The treatment of fractures of the mandibular condylar process(es) can be conservative or surgical. However, in many cases, a definitive judgment on the functional long-term outcome of the chosen therapy can only be given many years after the intervention. As a result, it is clearly useful to be able to review the effects of treatment undertaken at least 15 years previously. Even so, only two such studies have been identified. Therefore, the aim of the present study is to evaluate the current functional capacity of the mandibular condyles of 20 subjects who had had an uni- or bilateral fracture of the condylar process, on average 19 years ago. The individuals, who all had been treated conservatively, were compared with a control group of healthy volunteers matched for gender and age. Besides measuring maximum mouth opening (MMO), computerized axiographies in the sagittal plane were made for each condyle during MMO, maximum protrusion and maximum mediotrusion. In spite of the high degree of inter-individual variability in both groups, the data showed that the amount of condylar movement was in most cases greater in the control group. In general, it appears that the risk of developing functional problems after conservative treatment is highest in the case of a fracture of the condylar process accompanied by condylar luxation, rather than by a condylar dislocation or without it.

Bonding to alumina ceramic in restorative dentistry: clinical results over up to 5 years.

OBJECTIVES: The purpose of this clinical pilot study was to evaluate the resin bond to alumina ceramic in vivo when using a bonding method which had been shown to be successful in laboratory testing. METHODS: Seventeen resin-bonded all-ceramic bridges and splints fabricated from a glass-infiltrated alumina ceramic were tribochemically silica coated and resin bonded to their abutment teeth. The patients were recalled every 6 months to evaluate the restorations with regard to function and possible failures. RESULTS: Over a mean observation time of 3.8 +/- 1.6 years some ceramic fractures occurred. However, the resin bond between the teeth and the alumina ceramic always remained stable. CONCLUSIONS: Silica coating of alumina ceramic resulted in a durable resin bond over up to 5 years.