Effect of Aqueous Storage on Original and Repair Bond Strength and Residual Monomer Release of Fiberreinforced Composites.

PURPOSE: To evaluate the effects of aqueous storage on shear bond strength (SBS) and monomer release of fiberreinforced composites (FRCs). MATERIALS AND METHODS: Four unidirectional FRCs were tested, including one semi-interpenetrating polymer network (IPN) (ES, everStick) and three cross-linked polymer (CLP) FRCs (GT, GrandTec; TF, TenderFiber; DP, Dentapreg). The SBS of samples of original resin to fresh FRC with an intact oxygen inhibition layer (n = 30/group) and repair resin to FRC after surface treatment (n = 30/group) was evaluated after 6 and 12 months of storage in artificial saliva. Monomer release of polymerized resin-coated and uncoated FRCs was detected by high-performance liquid chromatography after immersion for 1 h, 1 day, and 7 days. RESULTS: After 6 months, a significant decrease in SBS was seen with ES-repair (p < 0.0001). After 12 months, significant decreases were seen with ES-original (p < 0.0001), ES-repair (p < 0.0001), and TF-repair (p = 0.0003). A significant reduction was also found for GT-original (p = 0.0254) and GT-repair (p = 0.0176). At 6 and 12 months, GT showed the highest SBS values, with DP-repair being statistically similar to GT at 12 months. For UDMA and bis- GMA, the greatest amounts of release were seen in uncoated specimens, followed by flowable resin-coated and viscous resin-coated specimens. CONCLUSION: Matrix composition, interfacial bonding, and resin coverage seem to account for differences in the aging behavior of FRCs. The semi-IPN material is likely to suffer most from the challenging oral conditions. CLP FRCs might be more stable over the long term. Coverage of FRCs with viscous resin is highly recommended to reduce residual monomer release.

Cytotoxicity of coated and uncoated fibre-reinforced composites.

OBJECTIVE: Currently, there are many fibre-reinforced composites (FRCs) available which differ in the type and volume fraction of fibres, pre-treatment of fibres and matrix composition. The aims of this in vitro investigation were to determine whether there is a difference in biocompatibility of FRCs and if coating FRCs with resin composites influences their cytotoxic potential. MATERIALS AND METHODS: Five different FRC materials were tested which were either uncoated or coated with flowable or viscous resin composite. Artificial saliva extracts were prepared according to USP-XXIII and ISO-10993 to determine cytotoxicity by testing cell viability and growth of primary human gingival fibroblasts (HGF) using MTT assay, LIVE/DEAD(®) assay and cell proliferation assay. The influence of eluates on fibres of the cytoskeleton was investigated by vimentin, tubulin and actinin immunostainings. A two-way ANOVA followed by Scheffe's post-hoc test, which included the factors FRC material and coating procedure, was performed to assess cytotoxicity. RESULTS: All extracts of FRC materials displayed minor cytotoxic potential on HGF cell viability, cell proliferation and integrity of the cytoskeleton. The type of FRC material significantly influenced cell viability (MTT assay) (p < 0.0001), whereas neither the presence of a coating nor the type of coating material resulted in altered cell viability. Distribution and organization of cytosolic fibres was not affected after HGF exposure to eluates. CONCLUSIONS: There is a lack of knowledge about the leaching behaviour of commonly available fully pre-impregnated FRCs and their interactions with coating materials. The coating of FRCs with resin composite materials did not impact biocompatibility.

Fiber-reinforced composite fixed dental prostheses in the anterior area: a 4.5-year follow-up.

STATEMENT OF PROBLEM: Currently, fiber-reinforced fixed dental prostheses (FRC FDPs) are a reliable treatment option for the restoration of single missing teeth in the anterior area. PURPOSE: The purpose of this study was to evaluate the survival of direct and semidirect fabricated FRC FDPs in the anterior area and to rate the quality of the outcome. MATERIAL AND METHODS: Twenty-four participants (12 men, 12 women) were included in the investigation. The prostheses were made of preimpregnated, unidirectional fiber-reinforced composite (FRC) (everStick, GC) by using a direct (n=18) or semidirect (n=6) technique. Eleven FRC FDPs had been placed in the maxilla and 13 had been placed in the mandible. Follow-up intervals were recorded, and the prostheses were classified as success (successful), survival (unfavorable event but still in vivo), or failure (lost). Quality was rated according to the modified United States Public Health Services (USPHS) or Ryge criteria. RESULTS: The FRC FDPs evaluated in this study showed an overall survival rate (success) of 72.6% and a functional survival rate (success + survival) of 85.6% (median follow-up 54 months). According to the USPHS/Ryge criteria, most of the restorations displayed excellent or good quality. Survival analysis was performed by the Kaplan-Meier method. CONCLUSIONS: The FRC FDPs evaluated in this study showed promising survival rates and good quality after a median follow-up period of 4.5 years (quartile range 3.5 to 6.3 years), thus indicating that FRC FDPs are reliable treatment options for the restoration of single missing teeth in the anterior area. The use of preimpregnated FRC materials with higher fiber content might improve the clinical fabrication of FRC FDPs but does not influence their long-term clinical survival.

Proximal contact tightness between direct-composite additions in the posterior dentition: an in vitro investigation.

PURPOSE: The aim of the study was to test whether a novel three-step matrix technique for posterior direct-composite additions creates sufficiently strong proximal contacts. MATERIALS AND METHODS: Contact tightness was measured between direct-composite additions and between original teeth on a model. Therefore, the frictional forces required to remove a straight, 0.05-mm-thick, metal matrix band inserted between adjacent teeth and held by a universal testing machine (Zwicki, Zwick GmbH, Ulm, Germany) were recorded. Measurements were taken at three time points to carry out reference analysis: at baseline, after removal of the maxillary right second premolar (tooth #15) to simulate a diastema, and after closure of the diastema by inserting two direct-composite additions with the three-step matrix technique on the maxillary right first premolar (tooth #14) and first molar (tooth #16). Measurements were performed in the maxillary right (first) and left (second) quadrants to document sagittal displacement. RESULTS: The original contact tightness values were between 1.65 ± 0.88 N and 3.05 ± 0.60 N in the first quadrant and between 1.23 ± 0.51 N and 2.18 ± 0.43 N in the second quadrant. After removal of tooth 15, values decreased significantly in the first quadrant and insignificantly in the second. After reconstruction, the contact tightness between teeth 14 and 16 was significantly stronger (tighter) (3.20 ± 0.80 N) than the originally measured contact tightness between teeth 14 and 15 (2.86 ± 0.64 N) and teeth 15 and 16 (1.65 ± 0.88 N) (p=0.006 and 0.001, respectively). CONCLUSIONS: Within the limitations of an in vitro investigation, this study has shown that by using a novel, three-step matrix technique, direct posterior composite additions can form sufficiently tight proximal contacts.

Replacing single missing teeth in the posterior region using direct composite restorations: Survival and clinical quality.

OBJECTIVES: The aim of this pilot study was to test the survival and clinical quality of frugal methods to replace single missing teeth in the posterior region with direct composite restorations of different categories. METHODS: We performed a detailed intraoral examination and assessed the clinical quality of the restorations according to modified FDI-criteria. Irreparable loss of a restoration was recorded as "failure" (F). Damaged restorations that could be repaired were defined as "survival with repair" (SR). Restorations without any unfavorable events were classified as "success" (S). RESULTS: The mean follow-up time of the restorations was 5.07 years (minimum = 1; maximum = 21.5), with 15.1% having a follow-up time of more than 10 years. Three unfavorable events were documented. Two restorations (3.8%) were classified as F, one restoration (1.9%) as SR, and the remaining 50 restorations (94.3%) as S. The estimated overall and functional survival rate at 5 years using the Kaplan-Meier method was 96.2% (confidence interval [CI]:85.5% to 99%) and 98% (CI:86.9% to 99.7%), respectively. Ninety-four percent of the restorations were evaluated as good or excellent clinical quality. Most restorations showed no periodontal complications, however, restorations in the mandible showed significantly more plaque accumulation (p=0.002). CONCLUSIONS: These conservative frugal methods to replace single missing teeth in the posterior region showed promising clinical survival data and quality parameters. CLINICAL SIGNIFICANCE: Direct composite restorations of different categories can be considered as additional treatment option for gap closure in specific clinical situations.

Assessment of different dyes used in leakage studies.

The goal of this in vitro study was to identify the most suitable dye for endodontic dye leakage studies, which could be a further step towards standardisation. The root canals of 70 extracted, single-rooted human adult teeth were enlarged to apical size 50 using hand instruments. The teeth were divided into seven groups (n = 10 each), and all root canals were completely filled by injection with one of the following dyes: methylene blue 0.5% and 5%, blue ink, black ink, eosin 5%, basic fuchsin 0.5% and drawing ink. Transverse root sections from the coronal, middle and apical part of the roots were examined, and the percentage of the dentine penetrated by dye was evaluated by software-supported light microscopy. In addition, the range of particle size of drawing ink particles was evaluated. There were conspicuous differences in the relative dye penetration into the root dentine and the penetration behaviour in the different root sections (two-way ANOVA, both p < 0.0001). One dye (drawing ink) penetrated less into the root dentine compared with all the others (p <0.0001). The particle size of this agent (0.1-2 microm) corresponds best with the size range of a representative selection of 21 species of pathogenic endodontic bacteria. Compared to the other dyes tested, drawing ink appears to be superior for use in endodontic dye leakage studies. The penetration behaviour into the root dentine of all the other dyes tested might be one factor that limits the applicability of these dyes in dye leakage studies.

Effort and costs of tooth preservation in supportive periodontal treatment in a German population.

OBJECTIVES: Assessment of effort (number of visits) and costs of tooth preservation 10 years after initiation of anti-infective therapy. MATERIAL AND METHODS: Data of 98 patients who had received active periodontal treatment 10 years ago by the same examiner were analysed to gather information on effort and costs of supportive periodontal therapy (SPT). Clinical examination, interleukin-1 (IL-1) polymorphism test, smoking, search of patients' files (i.e. initial diagnosis), as well as a questionnaire on medical history and socioeconomic data were performed. Statistical analysis was performed using multivariate linear regression analysis. RESULTS: During 10 years of SPT patients had 14.8+/-7.4 visits. Number of visits was statistically significantly higher for individuals with a mean plaque control record >or=24 %. The number of subgingival scalings per tooth ranged from 0 to 14 (mean: 1.17). On tooth level several confounders could be identified: tooth type, initial bone loss, furcation involvement, abutment status, and previous regenerative surgery (p

In vitro leakage associated with three root-filling techniques in large and extremely large root canals.

This study assessed the apical leakage of ultrasonically condensed root fillings in extremely large canals, compared to cold lateral condensation and thermoplastic compaction. Ninety single-rooted teeth were used. In 45 teeth canals were enlarged to size 70 (large). The remaining 45 canals were enlarged to size 140 (extremely large). Each set of teeth was subdivided into three root-filling groups (n = 15): (1) cold lateral condensation (LC); (2) thermoplastic compaction (TC); and (3) ultrasonic lateral condensation (UC). Teeth in all six subgroups were subjected to drawing ink penetration, cleared, and evaluated for linear apical dye leakage. Significantly deeper dye penetration (p < 0.04, Wilcoxon rank-sum test) was observed for LC than for UC. TC did not differ significantly from LC and UC. Dye penetration was significantly deeper (p < 0.0001) in canals enlarged to size 140 than to size 70, independent of root-filling method. Apical leakage associated with ultrasonically condensed root fillings was less than that with cold lateral condensation. It was consistently greater in extremely large canals than that in large ones.

A 6.5-year clinical follow-up of direct resin composite buildups in the posterior dentition: Introduction of a new minimally invasive restorative method.

OBJECTIVES: Restorative rehabilitation of missing single teeth in the posterior dentition is achieved primarily by dental implants or fixed dental prostheses. Here we introduce an uncommon, minimally invasive treatment option in order to close single tooth gaps. METHODS: The purpose of this study was to evaluate the clinical quality and survival of 45 direct composite buildups in the posterior dentition. A detailed clinical examination was performed, and restorations were rated qualitatively using the modified USPHS/FDI criteria. RESULTS: The mean extension of the direct composite buildups was 2.96 (1.12)mm per tooth. Interdental closures from both adjacent teeth had a significantly higher extension of the direct composite buildups than one-sided interdental closures (p=0.03). Patients with a history of prior tooth loss showed a significantly greater extension of direct composite buildups than patients without prior tooth loss (p=0.006). During the follow-up period, no restoration showed unfavorable events. The overall survival rate for the direct composite buildups was 100% after median follow-up of 78.96 months. The clinical quality rating indicated that most of the restorations (>94%) displayed excellent or good quality. No periodontal destruction, signs of gingival inflammation or increased plaque accumulation was observed. CONCLUSIONS: The posterior direct composite buildups evaluated in this study showed promising clinical survival data and excellent quality parameters after a median observation time of 6.5 years. CLINICAL SIGNIFICANCE: If a minimally or non-invasive treatment approach is indicated, posterior direct composite buildups provide a successful treatment alternative for the closure of single-tooth gaps to implant-supported or fixed dental prostheses.

Original and repair bond strength of fiber-reinforced composites in vitro.

OBJECTIVE: A great benefit of FRC technology is that, in case of minor failure events, restorations can be repaired or reinserted. However, various FRC materials are available, that differ in matrix composition and fiber pre-treatment. The aim of this investigation was, therefore, to evaluate original and repair bond strength of FRC materials. METHODS: Five fully pre-impregnated, unidirectional FRCs were selected, one semi-interpenetrating polymer network FRC and four cross-linked-polymer FRCs. The primary endpoint was the evaluation of shear bond strength (SBS) between FRC and composite resin, which was performed by a universal testing machine. For each FRC specimens were divided into control (original SBS, resin to fresh FRC with oxygen inhibition layer (OIL), n=30) and test groups (repair SBS, resin to FRC after removal of OIL and adhesive infiltration, n=30). RESULTS: The cross-linked-polymer FRC GrandTec(®) (12.4±5.4 MPa) yielded the highest control SBS, followed by the semi-interpenetrating polymer network FRC (everStick(®), 9.2±3.5 MPa). With everStick(®), repair led to a significant increase in the test SBS (14.6±5.8 MPa, p=0.01). SIGNIFICANCE: Control SBS was best with GrandTec(®) indicating that the material is superior in direct clinical application. Test SBS was significantly increased with everStick(®) which points at potential reparability and advantages in semi-direct or indirect fabrication of fiber-reinforced fixed partial dentures.

Recontouring teeth and closing diastemas with direct composite buildups: a 5-year follow-up.

OBJECTIVES: Adhesive resin composite technology enables dentists to add composite material to tooth surfaces to close gaps and reshape tooth form without cavity preparation. This option creates new possibilities for minimally invasive dentistry as the tooth shape, position and colour can be altered without loss of tooth substance. However, evidence-based data on direct composite buildups are rare. METHODS: The purpose of this study was to evaluate the outcome and to document the occurrence of unfavourable events and clinical findings of 176 direct composite buildups that had been performed in the Department of Conservative Dentistry, University Hospital Heidelberg, Germany, between 2002 and 2008. Outcome was categorised as failure (F), survival (SR) or success (S). Restorations still in place and without prior failure at follow-up were qualitatively rated using modified USPHS/FDI criteria. RESULTS: During the follow-up period, 30 restorations were found to have had unfavourable events or clinical findings. All restorations were repaired, and they remained in situ (SR). No complete loss (F) was recorded. The overall survival rate was 84.6% after 60 months (95%, confidence interval [CI]: 78.5 and 90.6). Clinical quality was rated excellent or good for most (>90%) of the restorations examined. CONCLUSIONS: The direct composite buildups observed in this study were found to have promising clinical outcome and good quality parameters after 5 years. If a noninvasive or minimally invasive treatment approach is indicated, direct composite buildups provide an acceptable treatment alternative for the aesthetic correction and reshaping of anterior teeth. CLINICAL SIGNIFICANCE: The application of direct composite buildups in clinical cases in which a non- or minimally invasive treatment approach is indicated provides an excellent treatment alternative for gold-standard treatment options like laboratory-made crowns and porcelain veneers. Restorations in the present investigation showed a functional survival rate of 100%, an overall survival rate of 84.6% after 5 years.

The assessment of dentofacial esthetics in restorative dentistry: a review of the literature.

BACKGROUND: The authors conducted a literature review to determine how dentofacial esthetics can be evaluated in restorative dentistry and which quantifiable clinical parameters can be used for this assessment of dentofacial esthetics. TYPES OF STUDIES REVIEWED: The authors selected 35 studies that focused on assessment strategies for dental professionals. The primary inclusion criteria were intraoral and extraoral esthetic assessment methods and indexes or rating scales evaluating esthetics in restorative dentistry. RESULTS: The studies' protocols and assessment methods were heterogeneous. The authors grouped the studies into six categories according to topic: golden proportion, soft-tissue measurement, smile and smile line assessment, orofacial indexes and scales, incisor proportion and angulation, and facial esthetics. These categories included various esthetic parameters, including the smile line, lip line, incisal offset, location of dental and facial midline, incisor angulations and width to height ratios of the maxillary anterior teeth, gingival contour, and root coverage and papilla height. These parameters should be considered when providing dental treatment in the anterior area, as they allow for quantification and objective judgment. CLINICAL IMPLICATIONS: The findings of this review might increase interest in a comprehensive dental esthetic index that allows for objective quantification and intrastudy and interstudy comparison of dental treatment outcomes.

Recontouring teeth and closing diastemas with direct composite buildups: a clinical evaluation of survival and quality parameters.

OBJECTIVES: Irregular tooth shape and position in the anterior maxilla and mandible are major aesthetic problems for patients. In recent years such conditions have increasingly been treated minimally or even non-invasively by recontouring teeth with direct composite resin buildups. Although clinical experience with this treatment option is promising, evidence-based data about longevity are limited. METHODS: The authors evaluated survival and quality of 327 composite buildups that were placed in 101 patients in the Department of Conservative Dentistry, University of Heidelberg, between 2002 and 2008. Follow-up intervals and failures were recorded. Quality was assessed by grading restorations (modified USPHS/Ryge critera) still in situ without adverse event during the follow-up period. RESULTS: After a mean follow-up interval of 27.8 months, 284 restorations were in situ and had no event. Forty-two restorations were in situ but had events that were mostly minor fractures of the composite resin. One restoration had been lost. Analysis of the time from insertion to any event or end of follow-up yielded an estimated 5-year survival rate of 79.2% (95% CI, 70.5-87.9). Quality was assessed by grading in situ restorations without event. More than 90% of graded restorations were categorized as "clinically excellent" (1) or "clinically good" (2). A correlation between those rated "clinically sufficient" or worse (≥3) and the follow-up period was observed. CONCLUSIONS: Direct composite buildups are aesthetic, functional, and biologically sound treatment options for recontouring teeth and closing diastemas with clinically promising survival rates. Therefore, tooth shape correction can be recommended in cases in which minimally invasive or non-invasive procedures on healthy teeth are indicated.

Treatment outcome of mineral trioxide aggregate: repair of root perforations.

INTRODUCTION: The use of biocompatible materials like mineral trioxide aggregate (MTA) may improve the prognosis of teeth with root perforations. METHODS: The treatment outcome of root perforations repaired between 2000 and 2006 with MTA was investigated. Twenty-six patients received treatment with MTA in 26 teeth with root perforations. Treatment was performed by supervised undergraduate students (29%), general dentists (52%), or dentists who had focused on endodontics (19%). Perforation repair by all treatment providers was performed using a dental operating microscope. Calibrated examiners assessed clinical and radiographic outcome 12 to 65 months after treatment (median 33 months, 81% recall rate). Pre-, intra-, and postoperative information relating to potential prognostic factors was evaluated. RESULTS: Of 21 teeth examined, 18 teeth (86%) were classified as healed. None of the analyzed potential prognostic factors had a significant effect on the outcome. CONCLUSIONS: MTA appears to provide a biocompatible and long-term effective seal for root perforations in all parts of the root.

Mineral trioxide aggregate or calcium hydroxide direct pulp capping: an analysis of the clinical treatment outcome.

INTRODUCTION: The use of mineral trioxide aggregate (MTA) might improve the prognosis of teeth after pulp exposure. The treatment outcome of teeth after direct pulp capping, either with mineral trioxide aggregate (MTA) or calcium hydroxide (controls), was investigated, taking into account possible confounding factors. METHODS: One hundred forty-nine patients treated between 2001 and 2006 who received direct pulp capping treatment in 167 teeth met the inclusion criteria. Treatment was performed by supervised undergraduate students (72%) and dentists (28%). Assessment of clinical and radiographic outcomes was performed by calibrated examiners 12-80 months after treatment (median, 27 months). RESULTS: One hundred eight patients (122 treated teeth) were available for follow-up (72.5% recall rate). A successful outcome was recorded for 78% of teeth (54 of 69) in the MTA group and for 60% of teeth (32 of 53) in the the calcium hydroxide group. The univariate analysis (generalized estimation equations model [GEE model] showed a significant difference in the success rate (odds ratio [OR], 2.36; 95% confidence interval [CI], 1.05-5.32; P = .04). In the multiple analysis (GEE model), the OR is marginally inside the nonsignificant range (OR, 0.43; 95% CI, 0.19-1.02; P = .05) when conspicuous confounding factors are stabilized (univariate analysis). Multiple analysis showed that teeth that were permanently restored >or=2 days after capping had a significantly worse prognosis in both groups (OR, 0.24; 95% CI, 0.09-0.66; P = .01). CONCLUSIONS: MTA appears to be more effective than calcium hydroxide for maintaining long-term pulp vitality after direct pulp capping. The immediate and definitive restoration of teeth after direct pulp capping should always be aimed for.

Mineral trioxide aggregate apical plugs in teeth with open apical foramina: a retrospective analysis of treatment outcome.

INTRODUCTION: Teeth with open apical foramina present a challenge during root canal treatment, and little is known about the clinical outcome of treatment in such teeth. This retrospective study assessed healing of teeth with open apices managed by the placement of mineral trioxide aggregate apical plugs. METHODS: Seventy-two patients with 78 teeth with apical resorption or excessive apical enlargement, treated between 2000 and 2006, were contacted for follow-up examination 12 to 68 months after treatment (median 30.9 months). Treatments were provided by supervised undergraduate students (27%), general dentists (32%), or dentists who had focused on endodontics (41%). The outcome based on clinical and radiographic criteria was assessed by calibrated examiners and dichotomized as "healed" or "disease." RESULTS: Of 56 teeth examined (72% recall), 84% were healed. Teeth without or with preoperative periapical radiolucency had a healed rate of 100% and 78%, respectively. None of the variables analyzed had a significant effect on the outcome. CONCLUSION: The results supported the management of open apical foramina with mineral trioxide aggregate apical plugs.