C5a complement receptor modulates odontogenic dental pulp stem cell differentiation under hypoxia.

AIM: Alterations in the microenvironment change the phenotypes of dental pulp stem cells (DPSCs). The role of complement component C5a in the differentiation of DPSCs is unknown, especially under oxygen-deprived conditions. The aim of this study was to determine the effect of C5a on the odontogenic differentiation of DPSCs under normoxia and hypoxia. MATERIAL AND METHODS: Human DPSCs were subjected to odontogenic differentiation in osteogenic media and treated with the C5a receptor antagonist-W54011 under normal and hypoxic conditions (2% oxygen). Immunochemistry, western blot, and PCR analysis for the various odontogenic differentiation genes/proteins were performed. RESULTS: Our results demonstrated that C5a plays a positive role in the odontogenic differentiation of DPSCs. C5a receptor inhibition resulted in a significant decrease in odontogenic differentiation genes, such as DMP1, ON, RUNX2, DSPP compared with the control. This observation was further supported by the Western blot data for DSPP and DMP1 and immunohistochemical analysis. The hypoxic condition reversed this effect. CONCLUSIONS: Our results demonstrate that C5a regulates the odontogenic DPSC differentiation under normoxia. Under hypoxia, C5a exerts a reversed function for DPSC differentiation. Taken together, we identified that C5a and oxygen levels are key initial signals during pulp inflammation to control the odontogenic differentiation of DPSCs, thereby, providing a mechanism for potential therapeutic interventions for dentin repair and vital tooth preservation.

A digital approach to robust and esthetic implant overdenture construction.

OBJECTIVE: Overdenture therapy is an important option for implant rehabilitation. However, numerous reports suggest that mechanical/technical complications and failures can limit therapeutic success. The goal of this report is to illustrate a digital approach to design and construction of a robust overdenture with high-esthetic value. MATERIALS AND METHODS: Beginning with new denture design to establish esthetic parameters, 3D modeling of a metal framework and the denture teeth are completed in a connected manner. This enables connection of rapidly printed, prototype dentition that is attached directly to the framework without intervening wax or acrylic components. Following evaluation of the dentition and required adjustments, the final dentition is milled from resin and processed to the selective laser sintered framework. RESULTS: The advantages of the digital workflow include the control of dimensions and strength of the framework, the esthetic relationship of the framework to the dentition and the facilitation of esthetic try-in of the dentition. CONCLUSION: Enhancing a robust overdenture can be readily achieved using a digital workflow. CLINICAL SIGNIFICANCE: The use of digital technology enables the clinical team to plan and produce prostheses with dimensions and contours that support long-term function and esthetics. The clinical chair time can be potentially reduced by use of digital design that facilitates try-in and reduces major errors by improved communication between the patient, dentist, and technician.

Diversity of the oral microbiome between dentate and edentulous individuals.

BACKGROUND: Measurement of saliva microbes is promoted as a way to detect oral and systemic disease, yet there is a multitude of factors that affect the oral microbiome. The salivary microbiome is influenced by oral biofilm of shedding (epithelial) and non-shedding (tooth) surfaces. METHODS: To gauge the ability of salivary microbial analytics to distinguish between edentulous and dentate oral conditions, we looked for differences in the saliva microbiome of subjects with and without teeth. Fifty-two dentate and 49 edentulous subjects provided stimulated saliva samples. 16S rRNA gene sequencing, QIIME-based data processing, and statistical analysis were done using several different analytical approaches to detect differences in the salivary microbiome between the two groups. RESULTS: Bacteria diversity was lower in the edentulous group. Remarkably, all 31 of the most significant differences in taxa were deficits that occur in the edentulous group. As one might expect many of these taxa are attributed to dental plaque and gingival sulcus associated bacteria. CONCLUSION: In sum, the measurement of 16S rRNA genes in the bacteria of the saliva can be used to reproducibly measure differences in the oral microbiome that occur with edentulism, mainly the lack of tooth and tooth-related structures.

Retrospective cohort analysis of maxillary overdentures retained by unsplinted implants.

STATEMENT OF PROBLEM: Implant therapy involving an unsplinted 2-implant-retained overdenture is well defined as a successful treatment for a patient with an edentulous mandible. However, a similar unsplinted implant therapy supporting a maxillary overdenture is not well characterized. PURPOSE: The purpose of this retrospective study was to evaluate maxillary overdentures retained by 4 unsplinted implants measuring implant survival, overdenture survival, and patient-reported outcomes. MATERIAL AND METHODS: Participants who had received an unsplinted implant-retained maxillary overdenture were included in the study. Participants presented for one denture recall appointment, during which comprehensive examination, including radiographs, was performed and clinical findings were recorded. Participants also completed the Oral Health Impact Profile-49 (OHIP-49) and a 20-item visual analog scale (VAS) satisfaction questionnaire. Nonparametric statistical tests were used to compare OHIP-49 and VAS scores across age, sex, time since overdenture insertion, mandibular dental status, smoking status, maxillary mucosal health, and overdenture hygiene. RESULTS: For the 44 participants, 3 of 4 implants failed in 1 individual. The cumulative implant survival rate was 98% (97.7% patient level). No prosthetic failures (that is, overdenture replacement) occurred, indicating a 100% prosthesis survival rate. The mean ±standard deviation OHIP-49 severity score was 23.6 ±26.0, and the mean ±standard deviation total VAS score was 179.2 ±29.4. Increased age was associated with lower OHIP-49 severity score (P=.036), and participants with unhealthy oral mucosa or denture stomatitis demonstrated significantly higher OHIP-49 severity scores (P=.003). CONCLUSIONS: In this retrospective evaluation, unsplinted implant-retained maxillary overdenture therapy was associated with high implant and prosthetic survival, as well as high patient satisfaction and quality of life. Age, sex, maxillary mucosal health, and mandibular dental status resulted in significant differences with respect to oral health-related quality of life and patient satisfaction, indicating that this treatment option may be ideal for certain patients.

Marginal Fit Evaluation of CAD/CAM All Ceramic Crowns Obtained by Two Digital Workflows: An In Vitro Study Using Micro-CT Technology.

PURPOSE: To evaluate the marginal fit of CAD/CAM all ceramic crowns made from lithium disilicate and zirconia using two different fabrication protocols (model and model-less). MATERIALS AND METHODS: Forty anterior all ceramic restorations (20 lithium disilicate, 20 zirconia) were fabricated from digital impressions using a CEREC Bluecam scanner. Two different digital workflows were used: a fully digital model-less approach and a printed model digital approach. The crowns were cemented on the respective prepared typodont teeth and marginal gap was evaluated using Micro-CT. Each specimen was analyzed in sagittal and trans-axial orientations, allowing evaluation of the marginal fit (vertical and horizontal) on each surface. Logarithmic transformation was used with a significance of 0.05. After that a reliability analysis was performed by re-measuring four randomized selected images for each specimen and performing intraclass correlations to determine any systematic bias in the measurements. RESULTS: Vertical measurements in the lingual, distal and mesial views had an estimated marginal gap ranging from 101.9 to 133.9 µm for lithium disilicate crowns and 126.4 to 165.4 µm for zirconia. No significant differences were found between model and model-less techniques. CONCLUSIONS: Both workflows are valid protocols for the fabrication of monolithic ceramic restorations. The use of a printed model did not improve the marginal fit of lithium disilicate or zirconia crowns. Both materials are also clinically acceptable, no matter which workflow was used to obtain the restoration.

Insulin-like growth factor binding Protein-3 suppresses osteoblast differentiation via bone morphogenetic protein-2.

Bone augmentation therapy is used in dental implantation. While techniques to induce bone formation are generally successful, the maintenance of bone mass is more difficult. Therefore, it is important to understand the mechanisms that regulate this process. Insulin-like growth factor-1 (IGF-1) is one of the most abundant growth factors that regulate bone mass, promote osteoblast differentiation, and accelerate bone formation. The activity of IGF-1 is regulated by IGF-binding proteins (IGFBPs). IGFBP-3 forms a ternary complex with IGF-1, extending its half-life in the circulating system. Therefore, IGFBP-3 acts as a stabilizer and transporter of IGF-1. Recent studies reported new IGF-1-independent functions of IGFBP-3 related with bone metabolism. In this study, we investigated the function of IGFBP-3 in osteoblast differentiation. Our results showed that IGFBP-3 decreases the expression of osteoblast differentiation markers, whose expression is enhanced by bone morphogenetic protein-2 (BMP-2). IGFBP-3 also reduced BMP-2 effect on ALP activity and mineral nodule formation. In addition, IGFBP-3 suppresses the activity of the Smad Binding Element (SBE) reporter, induced by BMP-2 signaling. These results suggest that IGFBP-3 inhibits osteoblast differentiation through the BMP-2 signal pathway, and that IGFBP-3 might play a role in bone mass maintenance in an IGF-1-dependent and -independent manner.

Fracture of layered zirconia restorations at 5 years: A dental laboratory survey.

STATEMENT OF PROBLEM: The use of ceramic restorations has significantly increased in recent years because of their esthetic properties and the high cost of noble metals. However, given the lack of long-term clinical trials and the limitations of in vitro studies, the durability of ceramic restorations is still questionable. PURPOSE: The purpose of this retrospective study was to determine the fracture rate of layered zirconia restorations at up to 5 years of clinical performance by using a dental laboratory survey model. MATERIAL AND METHODS: Data up to 5 years were collected from 2 commercial dental laboratories. Layered zirconia restorations returned to the laboratory for remaking because of failure (fracture) were identified and included. Restorations were categorized as anterior or posterior. Each category was further divided into complete coverage single crowns (SCs) and multiple unit fixed dental prostheses (FDPs). Fracture rates were compared and analyzed using the chi-square test (α=.05). RESULTS: A total of 31594 restoration records were reviewed and included 13419 anterior restorations (10134 SCs and 3285 FDPs) and 18175 posterior restorations (12810 SCs and 5365 FDPs). The overall fracture rate up to 5 years for all restorations (anterior and posterior) was 3.31%. The fracture rates for anterior restorations were less than for posterior restorations. The fracture rates for anterior SCs were approximately half those of the posterior SC fracture rate, and the combined fracture rate (anterior and posterior) was 3.25%. For FDPs, anterior FDPs fractured at a rate similar to that of posterior FDPs. The combined fracture rate (anterior and posterior FDPs) was 3.47%. CONCLUSIONS: Layered zirconia restorations displayed relatively low fracture rates in the relatively short term of 5 years.

Factors Influencing Removable Partial Denture Patient-Reported Outcomes of Quality of Life and Satisfaction: A Systematic Review.

PURPOSE: A systematic search of the literature was performed to identify and characterize articles reporting the influence of removable partial denture (RPD) therapy on satisfaction and quality of life (QoL). MATERIALS AND METHODS: The literature search for relevant articles published between January 1983 and March 30, 2013 was conducted using keyword searches of electronic databases and complimentary hand searches. The search strategy included the following keyword combinations (MeSH and free-text terms): fail, complication, surviv*, longevity, outcome, patient satisfaction or QoL, and denture or prosthes*, and partial and removable. Based on inclusion and exclusion criteria, articles focused on the effect of RPD therapy were reviewed and classified according to Strength-of-Recommendation Taxonomy (SORT) criteria. RESULTS: The combined search identified 997 publications; 198 duplicates were identified and removed, leaving 799 references for further evaluation. After abstract review, 209 articles were selected and read; 18 reports representing findings from 4002 patients were included. While two studies were prospective comparative investigations, the majority of studies represented cross-sectional and retrospective studies. Different instruments were used to measure oral health-quality of life (OHQoL) and satisfaction. Several investigations reported a significant association of satisfaction and QoL with either (a) age of the patient, (b) number of occluding dental units replaced, (c) replacement of anterior teeth, and (d) nature of the opposing arch. CONCLUSIONS: A paucity of detailed investigations concerning outcomes of RPD therapy was noted. Improvement in OHQoL or satisfaction following provision of RPDs was not consistently reported. There is little evidence supporting any association between patient-reported QoL or satisfaction with technical or biological parameters of therapy. Therapeutic success of tooth replacement using RPDs should be carefully considered and compared with alternatives.

RhoA-Mediated Functions in C3H10T1/2 Osteoprogenitors Are Substrate Topography Dependent.

Surface topography broadly influences cellular responses. Adherent cell activities are regulated, in part, by RhoA, a member of the Rho-family of GTPases. In this study, we evaluated the influence of surface topography on RhoA activity and associated cellular functions. The murine mesenchymal stem cell line C3H10T1/2 cells (osteoprogenitor cells) were cultured on titanium substrates with smooth topography (S), microtopography (M), and nanotopography (N) to evaluate the effect of surface topography on RhoA-mediated functions (cell spreading, adhesion, migration, and osteogenic differentiation). The influence of RhoA activity in the context of surface topography was also elucidated using RhoA pharmacologic inhibitor. Following adhesion, M and N adherent cells developed multiple projections, while S adherent cells had flattened and widespread morphology. RhoA inhibitor induced remarkable longer and thinner cytoplasmic projections on all surfaces. Cell adhesion and osteogenic differentiation was topography dependent with S < M and N surfaces. RhoA inhibition increased adhesion on S and M surfaces, but not N surfaces. Cell migration in a wound healing assay was greater on S versus M versus N surfaces and RhoA inhibitor increased S adherent cell migration, but not N adherent cell migration. RhoA inhibitor enhanced osteogenic differentiation in S adherent cells, but not M or N adherent cells. RhoA activity was surface topography roughness dependent (S < M, N). RhoA activity and -mediated functions are influenced by surface topography. Smooth surface adherent cells appear highly sensitive to RhoA function, while nano-scale topography adherent cell may utilize alternative cellular signaling pathway(s) to influence adherent cellular functions regardless of RhoA activity.

Electronic assessment of peri-implant mucosal esthetics around three implant-abutment configurations: a randomized clinical trial.

OBJECTIVES: To objectively assess the influence that three different implant-abutment interface designs had on peri-implant mucosal esthetics at 1 year post-implant placement via the pink esthetic score (PES). Additionally, to demonstrate the novel employment of a tablet-based digital imaging format to reliably assess and score clinical images as part of a multicenter clinical trial according to PES criteria. MATERIALS AND METHODS: Adult subjects (n = 141) with healed tooth-bound edentulous sites in the anterior maxilla as well as first premolar region were randomized to receive one of three different implant-abutment interface designs (conical interface = CI; flat-to-flat interface = FI; or platform switch interface = PS). Immediate provisionalization was performed with prefabricated titanium abutments, with definitive custom CAD/CAM zirconia abutments and all-ceramic cement-based crowns being delivered 12-week post-implant placement. Bilateral (anterior sites) or unilateral (premolar sites) digital clinical photographs were made at 1, 3, 6, and 12 months post-implant placement. Five calibrated faculty evaluators of different clinical backgrounds scored images during a 4-week timeframe on a standardized, tablet-based, digital imaging format. RESULTS: Six hundred and forty-nine clinical photographs were evaluated resulting in a total of 3245 sum PES values and 22,715 individual PES values. Faculty evaluator intra- and inter-rater reliability was found to be "strong" (ICC = 0.84) and "substantial" (ICC = 0.64), respectively, demonstrating repeatability of both the PES, evaluator calibration, and standardization of tablet-based scoring. All implant-abutment interface groups demonstrated significant improvements in mean sum PESs up to 1 year, with the largest improvement between restoration delivery and 6 months. No significant differences were found between groups in mean sum PESs both for individual study visits as well as for changes between study visits. CONCLUSIONS: No significant differences in mean sum PESs were found between subjects randomized to three different implant-abutment interfaces. However, significant differences were found as a function of time for all three groups, with the largest improvement in mean sum PESs occurring between definitive abutment and restoration delivery and 6 months. Use of electronic, tablet-based digital imaging scoring formats represents a novel and repeatable methodology for scoring PES images in large, multicenter clinical trials.

A Digital Approach to Improved Overdentures for the Adolescent Oligodontia Patient.

OBJECTIVE: The use of overdentures for treatment of oligodontia in adolescent patients using conventional techniques has described limitations. The aim of the case report is to demonstrate the use of CAD (Computer Aided Design) CAM (Computer Aided Manufacture) technology to produce an esthetic monolithic polymethylmethacrylate prosthesis that is retentive and stable on insertion. CLINICAL CONSIDERATIONS: Adolescent oligodontia patients are typically not suitable candidates for dental implant therapy. Overdentures provide interim or definitive restorative advantages. Given the important esthetic, psychological, and social functions of the prosthesis, an important therapeutic goal for the overdenture prosthesis is esthetics. A CAD-CAM approach to overdenture manufacture can provide a highly esthetic, strong, and retentive prosthesis. CONCLUSIONS: CAD-CAM manufacture of monolithic acrylic overdentures offer several advantages that include (1) improved planning and clinical communication, (2) high fidelity manufacture, (3) improved flexural strength, impact strength, and porosity, (4) improved prosthesis integrity and durability (due to the monolithic design), (5) CNC control of occlusal contacts, (6) high esthetic potential due to quality of bulk material and iterative design, and (7) archival nature of the digital prosthesis. CAD-CAM manufacture of monolithic overdentures is a viable approach to completing high value esthetic management of the adolescent oligodontia patient. CLINICAL SIGNIFICANCE: This case report identifies a new way to utilize CAD CAM technology to produce an improved overdenture for the oligodontia patient. It will be of interest to many and underscores the fundamental principles of smile design transfer to the digital environment. (J Esthet Restor Dent, 2016).

Prospective assessment of CAD/CAM zirconia abutment and lithium disilicate crown restorations: 2.4 year results.

STATEMENT OF PROBLEM: Single-tooth implant restorations are commonly used to replace anterior maxillary teeth. The esthetic, functional, and biologic outcomes are, in part, a function of the abutment and crown. PURPOSE: The purpose of this clinical study was to describe the implant, abutment, and crown survival and complication rates for CAD/CAM zirconia abutment and lithium disilicate crown restorations for single-tooth implants. MATERIAL AND METHODS: As part of a broader prospective investigation that enrolled and treated 141 participants comparing tissue responses at the conical interface (CI; AstraTech OsseoSpeed), flat-to-flat interface (FI; NobelSpeedy), and platform-switch interface (PS; NanoTite Certain Prevail) of single-tooth implants, computer-aided design and computer-aided manufacturing (CAD/CAM) zirconia abutments (ATLANTIS Abutment) and cemented lithium disilicate (e.max) crowns were used in the restoration of all implants. After 2.4 years in function (3 years after implant placement), the implant, abutment, and crown of 110 participants were evaluated. Technical and biologic complications were recorded. Demographic results were tabulated as percentages with mean values and standard deviations. Abutment survival was calculated with the Kaplan-Meier method. RESULTS: After 2.4 years, no abutments or crowns had been lost. Abutment complications (screw loosening, screw fracture, fracture) were absent for all 3 implant groups. Crown complications were limited to 2 crowns debonding and 1 with excess cement (2.5%). Five biological complications (4.0%) were recorded. The overall complication rate was 6.5%. CONCLUSIONS: CAD/CAM zirconia abutments restored with cemented lithium disilicate crowns demonstrated high survival on 3 different implant-abutment interface designs. No abutment or abutment screw fracture occurred. The technical complications observed after 2.4 years were minor and reversible. The use of CAD/CAM zirconia abutments with cemented lithium disilicate crowns is associated with high technical and biologic success at 2.4 years.

Complete-arch implant-supported monolithic zirconia fixed dental prostheses: A systematic review.

STATEMENT OF PROBLEM: Monolithic zirconia prostheses are emerging as a promising option in the implant-based rehabilitations of edentulous patients, yet their clinical performance is not fully documented. PURPOSE: The purpose of this systematic review was to assess the clinical performance of complete-arch implant-supported monolithic zirconia fixed dental prostheses. MATERIAL AND METHODS: The electronic databases PubMed, Science Direct, and Cochrane Library were searched for clinical studies on complete-arch implant-supported monolithic zirconia fixed dental prostheses. Human studies with a mean follow-up of at least 1 year and published in an English-language peer-reviewed journal up to June 2015 were included. Two independent examiners conducted the search and the review process. RESULTS: The search generated 903 titles. Eighteen qualifying studies were retrieved for full-text evaluation. Nine studies were included on the basis of preestablished criteria. Eight studies reported satisfactory clinical and esthetic outcomes. One study demonstrated prosthesis failure. Clinical studies are lacking on the long-term outcome of complete-arch implant-supported monolithic zirconia prostheses. CONCLUSIONS: Complete-arch dental implant restoration with monolithic zirconia is associated with high short-term success. Despite the many advantages and short-term favorable reports, studies of longer duration are necessary to validate the broad application of this therapy.

Fracture rate of monolithic zirconia restorations up to 5 years: A dental laboratory survey.

STATEMENT OF PROBLEM: The demand for ceramic restorations has increased over the past years because of their esthetic properties and the high cost of noble metals. However, the lack of long-term clinical studies and the difficulty of interpreting in vitro studies have placed the durability of ceramic restorations in doubt. PURPOSE: The purpose of this study was to determine the failure rate of monolithic zirconia restorations due to fracture up to 5 years of clinical performance. MATERIAL AND METHODS: Data were collected over 5 years from 2 commercial dental laboratories. Restorations that were returned to the laboratory for remake because of catastrophic failure (fracture) were identified and included. Restorations were categorized as anterior or posterior. Each category was further divided into complete-coverage single crowns (SCs) and multiple-unit fixed dental prostheses (FDPs). Fracture rates were compared and analyzed using a chi-square test (α=.05). RESULTS: A total of 39827 restoration records were reviewed and included 3731 anterior restorations (1952 SC; 1799 FDP) and 36096 posterior restorations (29808 SC; 6288 FDP). The overall fracture rate of up to 5 years for all restorations (anterior and posterior) was 1.09%. Fracture rates were 2.06% for all anterior restorations and 0.99% for all posterior restorations. Fracture rates were 0.97% for anterior SCs and 0.69% for posterior SCs, and the combined fracture rate (anterior and posterior) was 0.71%. For FDPs, 3.26% restorations fractured anteriorly and 2.42% fractured posteriorly, and the combined fracture rate (anterior and posterior) was 2.60%. CONCLUSION: Within the relative short-term evaluation of 5 years, restorations fabricated from monolithic zirconia material displayed relatively low fracture rates. Anterior restorations fractured at a slightly higher rate than posterior restorations, and FDPs fractured at a rate double that of SCs.

Osteoblastic and cytokine gene expression of implant-adherent cells in humans.

OBJECTIVES: Implant surface topography is a key determinant affecting osteoblastic differentiation and cell-cell signaling of implant-adherent cells. MATERIALS AND METHODS: To assess the early osteoinductive and cell-cell signaling events in adherent cells, commercially pure titanium implants (2.2 × 5 mm) with nanotopography (HF-treated TiO2 grit-blasted) were compared with micron-scale topography TiO2 grit-blasted (micron-scale, control) implants in vivo. Six implants (n = 3/surface) were placed in 10 systemically healthy subjects and removed by reverse threading at 1, 3, and 7 days. Gene expression profiles of adherent cells were interrogated using low-density RT-PCR arrays. RESULTS: Osteoinduction was not observed at day 1 on either surface. At 3 days, elevated levels of BMP6, osteopontin, and osterix (OSX) were observed in RNA of cells adherent to both micron-scale and nanotopography surfaces. Both surfaces supported osteoinductive gene expression at 7 days; however, modest elevations of most mRNAs and significantly higher OSX mRNA levels were measured for cells adhered to nanotopography implants. Further, chemokine and cytokine profiles including CXCL10, CXCL14, IL-9, IL-22, and TOLLIP were upregulated on nanotopographic surfaces as compared with microtopographic surfaces. CONCLUSIONS: Implants with superimposed nanoscale topography generate a greater induction of genes linked to osteogenesis and cell-cell signaling during the early phases of osseointegration.

Early molecular assessment of osseointegration in humans.

OBJECTIVE: To determine the early temporal-wide genome transcription regulation by the surface topography at the bone-implant interface of implants bearing microroughened or superimposed nanosurface topology. MATERIALS AND METHODS: Four commercially pure titanium implants (2.2 × 5.0 mm) with either a moderately roughened surface (TiOblast) or super-imposed nanoscale topography (Osseospeed) were placed (n = 2/surface) in edentulous sites of eleven systemically healthy subjects and subsequently removed after 3 and 7 days. Total RNA was isolated from cells adherent to retrieved implants. A whole-genome microarray using the Affymetrix Human gene 1.1 ST Array was used to describe the gene expression profiles that were differentially regulated by the implant surfaces. RESULTS: There were no significant differences when comparing the two implant surfaces at each time point. However, the microarray identified several genes that were differentially regulated at day 7 vs. day 3 for both implant surfaces. Functionally relevant categories related to the extracellular matrix (ECM), collagen fibril organization, and angiogenesis were upregulated at both surfaces (day7 vs. day3). Abundant upregulation of several differential markers of alternative activated macrophages was observed (e.g., MRC1, MSR1, MS4A4A, SLC38A6, and CCL18). The biological processes involved with the inflammatory/immune response gene expression were concomitantly downregulated. CONCLUSIONS: Gene regulation implicating collagen fibrillogenesis and ECM organization as well as the inflammatory/immune responses involving the alternative activated pathway are observed in implant adherent cells at early (3-7 days) after implantation. These gene expression events may indicate a pivotal role of collagen fibrillogenesis as well as immunomodulation in altering bone accrual and biomechanical physical properties of the implant-bone interface.

The effect of implant-supported removable partial dentures on oral health quality of life.

PURPOSE: Removable partial dentures (RPDs) represent standard treatment for partial edentulism despite major shortcomings. To alleviate these shortcomings, endosseous implants provide support and stability as well as contribute to maintenance of alveolar bone. This prospective, within subject, time series study evaluated patient-based outcomes of RPDs compared to implant-supported removable partial dentures (ISRPDs). The study hypothesis was that the ISRPD would substantially improve oral health quality of life for patients. MATERIALS AND METHODS: Seventeen patients requesting new mandibular Kennedy I or II RPDs received one 6-mm dental implant in one or both of the posterior edentulous areas. After healing, conventional RPDs were fabricated and delivered. Twelve weeks later, second-stage surgery was performed, and ball abutments with Clix attachments were inserted, thereby converting the prostheses to ISRPDs. Oral health quality of life was evaluated using the 49-item Oral Health Impact Profile (OHIP-49) questionnaire. The OHIP-49 was administered prior to treatment (baseline), at 6 and 12 weeks following RPD delivery and at 6 and 12 weeks following ISRPD conversion. Radiographic evaluation was performed at 6 and 12 weeks following ISRPD conversion. In statistical analysis, a fixed-slope random intercept variance components model took account of the multiple observations per person over time. RESULTS: In 17 subjects, 29 of 30 implants survived. The failed implant was replaced without complications. Abutment complications were limited to one abutment loosening and one attachment replacement. Minor prosthodontic complications were recorded. The OHIP-49 score reduced by 11.8 points, on average, at 12 weeks following ISRPD conversion (P = 0.011). CONCLUSIONS: Patients reported improved oral health following conversion to an ISRPD from RPD. The ISRPD involving short implants is one treatment option that should be considered when treatment planning Kennedy Class I and II patients.

Implant-supported fixed dental rehabilitation with monolithic zirconia: a clinical case report.

OBJECTIVE: Veneer chipping in bilayered ceramic restorations is a current problem reported with significant frequency. CLINICAL CONSIDERATIONS: This clinical report describes the use of a monolithic, implant-supported restoration with gingiva-colored ceramics. Good esthetic and functional results were achieved with no complications reported after 3 years. CONCLUSIONS: Prosthetic rehabilitation using monolithic zirconia may help to prevent complications associated with bilayered ceramics systems. Further studies are essential to provide long-term data about the performance of this type of prostheses.

Clinical outcomes of three different crown systems with CAD/CAM technology.

STATEMENT OF PROBLEM: Computer-aided design and computer-aided manufacturing (CAD/CAM) generated restorations are gaining popularity. However, limited clinical evidence is available for single-unit posterior CAD/CAM restorations fabricated with established and newer crown materials. PURPOSE: The purpose of this clinical study was to assess the restoration quality of and gingival response to CAD/CAM fabricated posterior single-tooth restorations with different processing technologies. MATERIAL AND METHODS: Twenty-two individuals in need of posterior complete coverage crowns were recruited under an institutional review board approved protocol. Teeth were randomized to 1 of 3 groups: metal ceramic, lithium disilicate, and monolithic zirconia. An unprepared or minimally restored tooth on the contralateral side was chosen as a control tooth for gingival measurements with each participant. Teeth were prepared and scanned intraorally by 1 of 3 experienced practitioners. A total of 32 restorations were digitally designed and fabricated with either milling technology or rapid-prototype printing and casting with conventional porcelain application. Restorations were evaluated with modified United States Public Health Service criteria for contour, marginal adaptation, occlusion, and shade. Gingival crevicular fluid volume and bleeding on probing were recorded preoperatively, at 1-month and 6-month postcementation visits. Polyvinyl siloxane impressions were made of the buccal margin of cemented restorations and evaluated with microcomputed tomography to assess marginal adaptation (horizontal discrepancy). The Mantel Haenszel row mean score was used to assess whether the crown systems differed with respect to the modified United States Public Health Service criteria. Linear mixed models were used to assess whether the average gingival volumes were affected by the explanatory variables (crown system, tooth status [treated vs control], or visit). A generalized estimating equation approach was used to assess whether bleeding on probing was affected by the explanatory variables. One-way ANOVA was used to assess marginal discrepancy values among the crown systems (α=.05 for all tests). RESULTS: Twelve metal ceramic, 10 lithium disilicate, and 10 zirconia restorations were fabricated for 22 participants. Zirconia restorations were significantly different from the other 2 crown systems (P<.001) with respect to occlusion. No occlusal adjustment was needed on 80% of the zirconia restorations. The average gingival crevicular fluid volumes did not differ among crown systems, between treated and control groups, or over time. The average horizontal marginal discrepancy was significantly different between lithium disilicate and zirconia crowns (P=.027), with zirconia crowns having the least amount of horizontal marginal discrepancy. CONCLUSIONS: Given the small sample size and limitations of this study, CAD/CAM-generated restorations for posterior teeth made from different materials had acceptable clinical results.

Micro-computed tomography evaluation of marginal fit of lithium disilicate crowns fabricated by using chairside CAD/CAM systems or the heat-pressing technique.

STATEMENT OF PROBLEM: No consensus exists concerning the acceptable ranges of marginal fit for lithium disilicate crowns fabricated with either heat-pressing techniques or computer-aided design and computer-aided manufacturing (CAD/CAM) systems. PURPOSE: The purpose of the study was to evaluate with micro-computed tomography the marginal fit of lithium disilicate crowns fabricated with different chairside CAD/CAM systems (Cerec or E4D) or the heat-pressing technique. MATERIAL AND METHODS: Lithium disilicate crowns were fabricated to fit an in vitro cast of a single human premolar. Three fabrication techniques were used: digital impressions with Cerec 3D Bluecam scanner with titanium dioxide powder, followed by milling from IPS e.max CAD for Cerec; digital impressions with E4D Laser scanner without powder, followed by milling from IPS e.max CAD for E4D; and fabrication from IPS e.max Press by using the lost-wax and heat-pressing techniques. Each crown was fixed to the cast and scanned with micro-computed tomography to obtain 52 images for measuring the vertical and horizontal fit. Data were statistically analyzed by 1-way ANOVA, followed by the Tukey honestly significant difference test (α=.05). RESULTS: The mean values of vertical misfit were 36.8 ±13.9 µm for the heat-pressing group and 39.2 ±8.7 µm for the Cerec group, which were significantly smaller values than for the E4D group at 66.9 ±31.9 µm (P=.046). The percentage of crowns with a vertical misfit <75 µm was 83.8% for Cerec and heat-pressing, whereas this value was 65% for E4D. Both types of horizontal misfit (underextended and overextended) were 49.2% for heat-pressing, 50.8% for Cerec, and 58.8% for E4D. CONCLUSIONS: Lithium disilicate crowns fabricated by using the Cerec 3D Bluecam scanner CAD/CAM system or the heat-pressing technique exhibited a significantly smaller vertical misfit than crowns fabricated by using an E4D Laser scanner CAD/CAM system.