Questions and answers on titanium-ceramic dental restorative systems : a literature study

OBJECTIVE: Titanium ceramics has become a topic of interest for prosthetic applications, thanks to the documented biocompatibility of commercially pure titanium. A number of concepts have been presented, including metal frameworks produced by casting or milling and a number of materials and methods for veneering. However, the concept has not reached a clinical breakthrough since failures have been reported from clinical experiences. METHOD AND MATERIALS: A PubMed search on the following key words was performed: titanium ceramics, long-term results. RESULTS: This review illustrates the fact that it is possible to have success with titanium ceramics on crucial criteria: fit and marginal adaptation, bond strength between metal and ceramics, and esthetic outcome. A review of clinical studies indicates a tendency for success rates to increase with time, which must be explained as a normal learning curve for a technical concept. The learning curve also includes development of materials and methods and the fact that there is a certain amount of technique sensitivity involved in the success rate for titanium ceramics. CONCLUSIONS: There is reason to believe that the outstanding clinical properties of titanium will further catalyze the development of titanium ceramics, and recent experiences clearly indicate that titanium ceramics, being a clinical product ready for use in fixed partial dentures, might already today challenge standard metal ceramics

Bonding between titanium and dental porcelain: A systematic review

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Porcelain bonding to titanium with two veneering principles and two firing temperatures

Dental literature, as well as dental laboratories, has described problems with ceramic veneering of titanium, while clinical and in vitro studies have reported good results. The objective of this study was to investigate the effect of firing temperature, thermo cycling, and veneering methods on bond strength between porcelain and titanium. Eighty titanium specimens were prepared with one of two methods: a bonding agent firing or an oxidation firing. During veneering, half of the specimens in each group were fired at 30 degrees C above and half at the manufacturer's recommended temperature. In the bonding agent group and in the oxidation group, half of each firing group was thermocycled. Bond strength was calculated in a three-point bending test. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analyses of the titanium and the porcelain fracture surfaces of one specimen from each subgroup was used in order to study the composition of the interface between titanium and porcelain surfaces after fracture. No significant difference in bond strength was found when firing at a higher temperature compared with firing at the recommended temperature. An oxidation firing before veneering yielded significantly higher bond strength in a three-point bending test than when firing with a bonding agent. SEM and EDS analyses indicated a higher frequency of titanium oxide fractures in the oxidation than in the bonding agent group.The main finding is that firing at 30 degrees C above the recommended temperature does not significantly affect bond strength between titanium and porcelain. SEM and EDS analysis indicate that fractures occur in the titanium oxide layer by oxidation firing and in the interface between titanium oxide layer and veneering material by bonding agent firing.This finding might indicate that three- point bending test is not a relevant method for determining bond strength in this case, since the firing methods might influence the ductility of the samples

Är korta tandbågar förenligt med god oral funktion hos äldre

Eftersom tandhälsan förbättras och dagens äldre kan förväntas få behålla fler tänder kommer det att ställas större krav på äldretandvården i framtiden. Samtidigt kommer tandvården att ha en begränsad tillgång på tandläkare som förväntas balansera samhällets allt mer restriktiva ekonomiska ersättning till tandvården mot patientens och de anhörigas ökade och därmed kostsammare krav på god funktionell tandvård. Mot denna bakgrund genomfördes en litteraturgenomgång i syfte att närmare kunna presentera sda-konceptet (”The shortened dental archkonceptet”) och dess möjliga kliniska applikation inom äldretandvården. En försiktig extrapolering som baserats på resultat från studier som rör patienter i yngre åldrar visar att ”the shortened dental arch-konceptet” även är tillämpbart inom tandvården för äldre

On the Accuracy of Some In Vitro Models for Mechanical Studies of Maxillary Removable Partial Dentures

OBJECTIVES: Comparative in vitro/in vivo studies show wide differences in functional strain magnitudes and patterns of functional strain distribution in prosthetic devices. The aim of this study was to evaluate the accuracy of three in vitro models for biomechanical studies of prosthetic devices. METHODS: Strain gages were attached to the test RPDs of six subjects. In vitro maxillary models with simple (model A), intermediate (model B) and advanced (model C) features for the anatomical simulation of supporting structures were manufactured for each subject. The dentures were subjected to two separate series of standardized functional and laboratorial loading tests. The principal maximum strain value (epsilon (1)) obtained for each gage and experiment was used to calculate the intra-experiment variance and inter-experiment variance for the in vivo and in vitro experiments. The integrated strain gage difference value between the in vitro and in vivo data (Sigma(diff)) was calculated for every loading test and compared to the in vivo inter-experiment variance with ANOVA and Scheffes test. RESULTS: The bite forces recorded were similar for each subject and loading position and between the two loading sessions. The inter- and intra-experiment variance was found to be higher for in vivo loadings than for in vitro. Results showed that the (Sigma(diff)) values for model B and model C were significantly different from the in vivo strain interexperiment variance (p<0.05). SIGNIFICANCE: This study showed that the anatomical simulation of in vitro models is insufficient to allow for accurate mechanical analyses of maxillary RPDs and that only simple verifications of the strain levels in prosthetic appliances can be attained in vitro

All-ceramic Fixed Partial Dentures Designed According to the DC-Zirkon Technique. A 2-year Clinical Study

The aim of the present in-vitro study was to compare the fracture strength of all-ceramic Fixed Partial Dentures supported by tooth-analogues and periodontal membrane with the same supported by dental implants. As ceramics are highly brittle, they cannot withstand deformations of more than 0.1% without fracturing. Hence, when planning an all-ceramic FPD, it is essential to evaluate abutment sup-port, as the fracture strength of all-ceramic constructions depends on the stability of the support to reduce strain in the beam of the prosthe-sis. The support provided by implants differs, however, from the sup-port provided by natural teeth as the implants are anchored directly in the bone with no intermediate tissue. One question that arises is whether strain and stress in the prosthesis are lower when the prosthe-sis is loaded on implants compared to natural teeth and hence if all-ceramic FPDs benefit from implant support. Twenty-four three-unit all-ceramic FPDs-12 supported by two dental implants and 12 by two tooth-analogues serving as end abutments-were made. All FPDs were subjected to preloading in a preloading procedure and subsequently subjected to load until fracture occurred. Load at fracture were regis-tered and comparisons between the two groups were made. The loads at fracture were statistically significant higher in the group supported by implants compared to the group supported by tooth-analogues (p = 0.003). Within the limitations of this in-vitro study, the following con-clusions can be drawn: All-ceramic fixed partial dentures can be used in combination with dental implants. The solid support gained from implants might thus be beneficial for the outcome of such treatment due to decreased strain and stress levels in the prosthesis when loaded on implants compared to when loaded on natural teeth. Clinical stud-ies are, however, needed to confirm these findings as there are more factors that influence the final clinical outcome

A prospective study of implant-supported full-arch yttria-stabilized tetragonal zirconia polycrystal mandibular fixed dental prostheses : three-year results

PURPOSE: The development of high-strength oxide ceramic materials has led to increased interest in all-ceramic fixed dental prostheses (FDPs). Success rates reported in clinical studies for all-ceramic FDPs based on high-strength oxide ceramic materials reportedly approach those of porcelain-fused-to-metal FDPs. These reconstructions, however, are still of limited size and have mainly concerned FDPs supported by natural teeth. The purpose of this study was to evaluate the clinical performance of multiunit all-ceramic FDPs supported by dental implants. MATERIALS AND METHODS: Ten patients received mandibular yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) FDPs manufactured according to the Cercon technique and supported by four Astra Tech implants. Nine patients received 10-unit FDPs and one patient received a 9-unit FDP. The FDPs were cemented with Panavia F 2.0 onto individually prepared titanium abutments. The FDPs were evaluated at baseline and after 12, 24, and 36 months. RESULTS: At the 3-year follow-up, all FDPs were in use, and all patients were fully satisfied with their treatment. None of the reconstructions had fractured. Superficial chip-off fractures of the veneering porcelain were, however, observed in nine patients (34 of 99 units, 34%). CONCLUSION: Results from this 3-year study suggest that implant-supported full-arch Y-TZP FDPs manufactured according to the Cercon technique should be viewed as a treatment alternative cautiously. A better understanding of the factors resulting in chip-off fractures is needed, together with longer follow-up studies involving larger numbers of patients, before the material and technique can be recommended for general use

Implant periapical lesion

One complication in implant dentistry is the implant periapical lesion. This case report describes a 30-year-old man who after an injury was treated with a single implant that caused a fistula that appeared four months after the implant installation. Proper pharmaceutical intervention was not successful. The fistula did not disappear until the apical part of the implant together with granulomatous tissue was surgically removed. It is concluded that an extended period of pain after implant installation might be an early indication that the treatment is not uneventful, that a fistula always should lead up to a fistulography, and that the condition can be successfully treated with surgery

Use of Abutment-teeth vs. Dental Implants to Support All-ceramic Fixed Partial Dentures : An In-vitro Study on Fracture Strength

The aim of the present in-vitro study was to compare the fracture strength of all-ceramic Fixed Partial Dentures supported by tooth-analogues and periodontal membrane with the same supported by dental implants. As ceramics are highly brittle, they cannot withstand deformations of more than 0.1% without fracturing. Hence, when planning an all-ceramic FPD, it is essential to evaluate abutment sup-port, as the fracture strength of all-ceramic constructions depends on the stability of the support to reduce strain in the beam of the prosthe-sis. The support provided by implants differs, however, from the sup-port provided by natural teeth as the implants are anchored directly in the bone with no intermediate tissue. One question that arises is whether strain and stress in the prosthesis are lower when the prosthe-sis is loaded on implants compared to natural teeth and hence if all-ceramic FPDs benefit from implant support. Twenty-four three-unit all-ceramic FPDs-12 supported by two dental implants and 12 by two tooth-analogues serving as end abutments-were made. All FPDs were subjected to preloading in a preloading procedure and subsequently subjected to load until fracture occurred. Load at fracture were regis-tered and comparisons between the two groups were made. The loads at fracture were statistically significant higher in the group supported by implants compared to the group supported by tooth-analogues (p = 0.003). Within the limitations of this in-vitro study, the following con-clusions can be drawn: All-ceramic fixed partial dentures can be used in combination with dental implants. The solid support gained from implants might thus be beneficial for the outcome of such treatment due to decreased strain and stress levels in the prosthesis when loaded on implants compared to when loaded on natural teeth. Clinical stud-ies are, however, needed to confirm these findings as there are more factors that influence the final clinical outcome

Implant periapical lesion. A case series report.

One complication in implant dentistry is the implant periapical lesion-IPL--which is a lesion around the apex of a stable implant diagnosed radiographically as a radioluscency in the bone at the apical part of an implant.The IPL can perform with or without clinical symptoms such as tenderness, swelling, suppuration and fistulation. This report describes 4 cases of IPL which were treated surgically with sectioning and removal of the affected portion of a stable implant and thorough debridement of the granulomatous tissue around it. This treatment was, up to 4 years after treatment, successful in all 4 cases. It can also from this report be concluded that IPL is a rather rare condition and that it can occur at any stage of implant treatment, in these cases from 4 months up to 11 years after implant installation. Finally there is a discussion about the aetiology of IPL and a comparison to findings in other reports on IPL and it is concluded that it is difficult to claim that there is a single cause to IPL. Rather it is evident that the condition might be a sequel of the summation of many possible causes.This summation exceeds the local biological threshold for the individual patient