Chairside quadrant rehabilitation: material selection in conditions with limited space.

The significantly faster fabrication technique of chairside restorations with the aid of the Cerec Primemill milling unit makes it possible to restore an entire quadrant in a reasonable amount of time. Furthermore, the procedure described in this article made it possible to use a new type of medium-strength ceramic that achieved a very good esthetic result overall.

A three-dimensional morphometric study on the position of temporomandibular joints.

OBJECTIVES: To address the controversy, in which indications average value articulation is suitable or to what extent individual registrations, especially using the facebow, should be applied, a quantification of the variability of relevant anatomical landmarks is necessary. The goal of this study was to investigate the mean and natural bandwidth of the parameters describing articulation. METHODS: Significant landmarks were measured on three-dimensional (3D) cone beam computed tomography (CBCT) scans of 120 arbitrarily selected individuals. The bandwidth and mean values of the anatomical relations were calculated. RESULTS: The mean arm length of the Bonwill triangle was 103.3 mm, with a range of 90.2 mm (minimum) to 117.9 mm (maximum), and a mean base length of 99.6 mm, with a range of 85.2 mm to 112.6 mm. There was a high correlation between the length of the left and right arms, but not between the arms and the base. The mean height of the Bonwill triangle, measured between the condyles and the occlusal plane, resulted in 34.3 mm, with a range of 21.0 mm to 47.2 mm. The mean value of the Balkwill angle was 20.4 degrees, with a range of 9.0 degrees to 27.6 degrees. The angle between the Camper's line and the occlusal plane averaged around 7 degrees. CONCLUSIONS: This study presents the bandwidth of anatomical relations necessary for articulation systems. The results are specific for males and females. The relevant parameters offer a high symmetry between the right and left sides. Additionally, the results show that the Bonwill triangle is more likely to be isosceles than equilateral. CLINICAL SIGNIFICANCE: The knowledge of the anatomical bandwidth of temporomandibular joint (TMJ) positions in relation to the dentition allows the simulation of software- controlled virtual articulators and the substitution of facebows.

Accuracy of chairside-milled CAD/CAM drill guides for dental implants.

PURPOSE: To describe a chairside method for producing implant guides based solely on digital data and present a first assessment of in vitro accuracy on plaster models. MATERIAL AND METHODS: Twenty-four implants were planned and pilot drillings were performed according to a new protocol, which is based on the registration of CBCT and CAD/CAM data. Chairside-milled one-piece drill guides were used to transfer the virtual plan into reality. Accuracy measurements were acquired. RESULTS: Chairside-milled drill guides were successfully fabricated and accuracy for pilot drillings was between 0.17 and 1.3 mm. CONCLUSION: Within the limits of this experimental study, chairside-milled drill guides are feasible and do not require any preparation before CBCT scanning.

The Capacity to Change the Lightness of Discolored Tooth Substrates by Means of Minimally Invasive Restorations: Perception by Dentists, Dental Technicians, and Laypersons

PURPOSE: To evaluate the minimal ceramic thickness needed to increase the lightness by one value by means of glass-ceramic restorations perceived by dental technicians, dentists, and laypersons. MATERIAL AND METHODS: A total of 15 assessment pairs (reference and test samples) were formed using glass-ceramic blocks in four different colors. Each assessment pair was comprised of two underground blocks differing in one value of lightness. On top of the underground blocks, glass-ceramic platelets were cemented in five different thicknesses (0.1 to 0.5 mm) and in the same color as the reference. Dental technicians, dentists, and laypersons (n = 41/group) were asked to determine the presence of a color difference between the two samples under standardized lighting conditions. The threshold ceramic thickness was defined as the thickness at which ≥ 50% of the evaluators were not able to perceive a difference within an assessment pair. The thresholds were analyzed, and groups were compared by applying chi-square test (P < .05). RESULTS: The majority of dentists and dental technicians (> 50%) detected a lightness difference between the test and reference samples up to a ceramic thickness of 0.5 mm. The majority of laypersons (≥ 50%) did not perceive a lightness difference with ceramic thickness of 0.5 mm. If separated by the different color changes, the threshold ceramic thickness started at 0.4 mm and varied within the groups of evaluators and by the lightness of the assessed color. CONCLUSION: A considerable number of evaluators perceived a lightness difference when minimally invasive ceramic restorations of 0.5-mm thickness were applied. The threshold ceramic thickness, however, was reduced when the lightness of the substrate was lower.

Radiographic results of osteotome-driven maxillary sinus floor elevation without grafting materials after 17.5 years radiographic evaluation of minimally-invasive sinus grafting.

BACKGROUND: There is growing evidence that minimally invasive sinus augmentation works without the use of filler materials. This study assessed the bone integration and sinus projection of single-unit implants in the maxilla, which were placed approximately 18 years ago using a modified filler-free osteotome technique. METHODS: Sixteen of the 24 treated patients of a former publication (treatment was performed between 2001 and 2004) were reassessed after a mean implant loading period of 17.5 years. The treated posterior areas were evaluated using cone-beam computed tomography (CBCT), and as a primary outcome parameter, sinus projection was determined in sectional views at the mesial, distal, buccal, and oral sites. Additionally, the percentage of alveolar bone contact was determined with respect to the implant length. Conventional radiographs were used to determine marginal bone levels. Additionally, plaque, bleeding on probing, and probing pocket depth were measured. The reconstructions were checked for chipping and other technical complications such as loss of retention, screw loosening, and screw fracture. RESULTS: The mean age of the included patients was 72.8 ± 8.5 years. Two implants were lost. Therefore, fourteen implants were available for CBCT evaluation. The highest sinus projection of 2.1 ± 1.7 mm was observed in the distal aspect, while it was 1.1 ± 1.5, 0.9 ± 1.2, and 0.9 ± 1.1 mm at the mesial, buccal, and oral sites, respectively. The maximal sinus projection in one case was 6.7 mm. The percentage calculation of osseous implant integration (in mm ± standard deviations) with respect to the selected implant length at the mesial, distal, buccal, and oral sites showed values ranging from, 87.9 ± 16.0, 78.4 ± 20.3, 91.0 ± 12.5, and 90.5 ± 11.1%, respectively. Five implants displayed probing pocket depths of more than 4 mm with bleeding; all implants had less than 1 mm of bone loss in the observation period, that is, implants had mucositis. Six of 14 crowns showed small chippings within the ceramic veneering. One case of screw loosening was reported in medical history. DISCUSSION: This study showed that implant placement in non-augmented sinuses resulted in good clinical results. The sinus projection, even if persistent and present, leads to no functional impairments. Given adequate maintenance, marginal bone levels remain constant and peri­implant health can be observed. Moreover, these results represent only a small cohort; and therefore, should be interpreted with caution. However, in view of the existing literature, these highly promising results are in line with other findings. CLINICAL SIGNIFICANCE: To the best of our knowledge, this dataset is the report with the longest follow-up. Overall, implants placed in the sinus without fillers represent a valuable alternative for tooth replacement in a minimally interventional manner.

Current status and perspectives of mucogingival soft tissue measurement methods.

UNLABELLED: The morphologic and metric assessment of mucogingival soft tissue dimensions is of great multidisciplinary clinical and academic interest, in order to quantify and monitor gingival changes while in treatment, e.g., during periodontal, restorative, prosthetic, orthodontic, or implant therapy. Pink esthetics play an increasingly important role in the overall treatment success, and therefore have to be monitored throughout therapy. The purpose of this article was to identify and summarize methods, which aim at quantifying gingival dimensions in terms of morphology, thickness, and volume, with respect to their accuracy and practicability. The introduced measurement methods should further facilitate personalized treatment planning and monitoring. CLINICAL SIGNIFICANCE: Mucogingival esthetics play an increasingly important role whenever treatment results are evaluated. Several qualitative and (semi)quantitative methods for measuring soft tissue dimensions are available. New methods like CAD/CAM (computer-aided design and computer-aided manufacturing) technologies are emerging and allow practitioners to reliably monitor their patient's soft tissues throughout therapy. Future improvements may help to develop better treatment strategies in terms of optimized preservation and creation of gingival morphology, especially in the esthetic zone.

Effect of two self-adhesive cements on marginal adaptation and strength of esthetic ceramic CAD/CAM molar crowns.

PURPOSE: This study evaluated the effects of adhesive cements on marginal adaptation and fracture resistance of ceramic molar crowns. MATERIALS AND METHODS: Seventy-five extracted maxillary molars were selected. The occlusal morphology of 15 molars (control) was scanned and transferred to the crowns in the test groups by CAD/CAM. Sixty molars received full-coverage crown preparations with 6-degree axial taper, 1.0-mm shoulder, and 2.0-mm occlusal reduction. They were assigned to four groups, and pulpal pressure was simulated. The 15 crowns in each test group were seated with resin-based self-adhesive cements, Rely-X (RX) and Multilink (MS), one multistep bonded adhesive luting composite resin, Variolink (VL), and glass-ionomer cement, Ketac Cem (KC). Test and control molars were subjected to thermal and mechanical fatigue stress (TMS: 12,000 x 5 degrees C to 50 degrees C; 2.4 million x 49 N) for 18 days in a masticator. Marginal adaptation ["continuous margin%" (CM%)] of the crowns was determined by scanning electron microscopy (200x). Finally, molars were occlusally loaded until fracture in a testing machine, and fracture load (N) was recorded. Marginal adaptation and strength data were statistically analyzed. RESULTS: TMS significantly (p < 0.001) reduced CM% in all groups. After TMS, CM% at the cement-dentin interface was significantly (p < 0.001) higher for RX than for all other cements. At the crown-cement interface both self-adhesive cements MS and RX had significantly better CM% than VL (p < 0.05) and KC (p < 0.001). Fracture resistance of natural untreated molars was significantly (p < 0.001) higher than that of experimental crowns. Fracture resistance of RX cemented crowns was significantly (p < 0.05) higher than that of other crowns. Occlusal morphology significantly influenced fracture resistance (p < 0.05). CONCLUSIONS: Self-adhesive cement RX offers a valid alternative to multistep resin-based luting composite with respect to marginal adaptation to dentin and fracture resistance. The latter is also influenced by occlusal morphology, necessitating careful monitoring of occlusal contacts.

Strength of CAD/CAM-generated esthetic ceramic molar implant crowns.

PURPOSE: One-visit in-office CAD/CAM fabrication of esthetic ceramic crowns as a superstructure for posterior implants is quite new. The aim of the study was to evaluate the strength of esthetic ceramic CAD/CAM crowns with varied occlusal thickness and seated with adhesive and nonadhesive cements on titanium and zirconia abutments. MATERIALS AND METHODS: Esthetic ceramic CAD/CAM-generated molar crowns (n = 15 per group) with occlusal thicknesses of 0.5 mm and 1.5 mm were seated on titanium (1) and zirconia (2) abutments: noncemented (a) and with nonadhesive cement (b) or 2 adhesive resin-based cements (c) and (d). In addition, 15 molar crowns with 5.5-mm occlusal thickness were seated on short zirconia abutments (3) using cements (c) and (d). All crowns had the identical occlusal morphology and were loaded with a crosshead speed of 0.5 mm/min until fracture. Load data were analyzed using 2-way ANOVA, the Scheffé test, and Weibull probability of failure analysis. RESULTS: Fracture loads of 1.5-mm occlusal thickness crowns (a, b, c, d) were higher (P < .001) than those of 0.5-mm crowns (except for group ld). Occlusal 5.5-mm crowns on short zirconia abutments had similar (2c) or less (2d) strength than the respective 1.5-mm crowns. Nonadhesive crowns (1b, 2b) were weaker (P < .001) than adhesive crowns (1c, 1d, 2c, 2d). Fracture loads of 0.5- and 1.5-mm crowns were significantly higher on titanium than on zirconia abutments with both cements. Adhesive cement d generally showed higher fracture loads than c on both titanium and zirconia. CONCLUSION: Esthetic ceramic CAD/CAM molar implant crowns gained high strength with adhesive cements on both titanium and zirconia implant abutments compared to nonadhesive cementation.

Effects of de- and remineralization of dentin on bond strengths yielded by one-, three-, and four-step adhesives.

PURPOSE: To assess the effect of different peri- and intertubular dentin mineralization conditions and etching on shear bond strength in vitro. MATERIALS AND METHODS: One hundred fifty crowns of extracted bovine incisors were embedded in resin and ground to expose the buccal coronal dentin. Sixty specimens were subjected to a demineralizing solution (DS) and another 60 teeth to a bacterial-based laboratory caries model (S. mutans, SM). Thirty specimens of each demineralization protocol (DS and SM) were randomly selected and remineralized (-R). Thirty sound dentin specimens served as control (C). Resin composite buildups (Tetric) were bonded after application of one of the following adhesives: a one-step self-etching adhesive (Xeno III), and a self-etching adhesive (Syntac Classic) without (three-step) and with prior additional 35% phosphoric acid etching (etch-and-rinse, four-step). Teeth were subjected to shear bond strength testing in a universal testing device at a crosshead speed of 0.5 mm/min (Ultradent method). RESULTS: Bond strength value for group C ranged from 6.3 to 8.4 MPa (p > 0.05). DS and DS-R samples showed in creased bond strength with the one-step adhesive (11.6 MPa, p < 0.05), whereas the three-step adhesive with additional etching showed decreased bond strength (3.2 MPa, p < 0.05). SM samples showed the lowest bond strength of all adhesive systems (range 1.1 to 1.5 MPa, p > 0.05). Remineralization showed no effect on the latter group. CONCLUSION: The degree of mineralization of the dentin is important for adhesion. Additional etching with phosphori acid reduced bond strength of a three-step adhesive.

Effects of total and selective bonding on marginal adaptation and microleakage of Class I resin composite restorations in vitro.

This study assessed the marginal integrity and microleakage of standardized Class I resin composite restorations when placed with either "total" or "selective bonding" techniques. Sixty standardized Class I cavities comprising the main fissure system were prepared (9 mm length and 7 mm width). Cavity depth was set at 2.5 mm. In cavities where a glass ionomer liner was placed, the cavity was deepened by an additional 0.5 mm. In "total bonding" specimens, enamel and dentin were conditioned using a four-step adhesive system (Syntac Classic). In teeth with "selective bonding," a chemical curing conventional glass ionomer cement (GIC; Ketac Fil) and light-curing resin-modified glass ionomer liner (RMGI; Vitrebond) or three-step adhesive bonding liner (Syntac) were applied. The cavity margins of the latter specimens were finished with water-spray, acid-etched and a bonding agent was applied. All restorations were placed in two oblique increments. Totally bonded ceramic inlays (Cerec) served as the control. All specimens were subjected to thermo-mechanical loading (1.2 Mio cycles) and marginal quality and microleakage were assessed. The highest percentage of margins rated as "perfect" was found in selective bonding samples with glass ionomer liners and totally bonded inlay restorations. All the other groups showed significantly decreased marginal quality (p < 0.05). The same results were found for the microleakage assessment. The authors of the current study concluded that the application of a GIC liner significantly improved the overall marginal adaptation of direct Class I restorations. The use of an adhesive bonding agent for cavity sealing as currently used is not recommended.

Sinus floor elevation using an osteotome technique without grafting materials or membranes.

This retrospective study aimed to radiographically assess sinus floor remodeling after using a modified osteotome technique without graft materials or membranes. After pilot drilling, residual bone was fractured and raised with the schneiderian membrane to the final implant length using osteotomes. Self-tapping implants were placed, and restorations were placed 6 months later. Twenty-four patients were available for follow-up after a mean observation period of 17.6 +/- 8.4 months. The implant survival rate at that time was 100%. Bone filling around the implants was measured and compared with baseline digital radiographs. New bone formation was 86.3% +/- 22.1% mesially and 89.7% +/- 13.3% distally. In nine cases, digital volume tomography was used to verify regeneration. Within the limitations of this study, use of the schneiderian membrane led to considerable bone regeneration, and good clinical success was achieved despite the omission of graft materials.

Fit of all-ceramic posterior fixed partial denture frameworks in vitro.

The objective of this study was to evaluate, by scanning electron microscopy, the marginal and internal fit of all-ceramic three-unit fixed partial denture (FPD) frames fabricated by computer-assisted design/computer-aided machining (CAD/CAM) and CAM techniques using blocks of infiltration ceramic, high-strength yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) zirconia sinter ceramic, high-strength dense sintered Y-TZP zirconia ceramic, and glass ceramic. Slip-cast infiltration ceramic was used as a traditional control. The cementation interface widths of the FPD frame copings on butt (A) shoulders of Cerec In-Ceram zirconia (A1, 53 +/- 17 microm) were smaller than those of slip-cast In-Ceram zirconia (A6, 113 +/- 25 microm). Cerec Y-TZP zirconia (A2, 53 +/- 9 pm) and DCS Y-TZP zirconia (A4, 32 +/- 6 microm) interfaces were both significantly smaller than those of Cercon Y-TZP zirconia (A5, 120 +/- 6 microm). Internally, A2 (103 +/- 14) interfaces were smaller than A4 interfaces (144 +/- 15 microm). On chamfer shoulders (B), Cerec Y-TZP zirconia (B1, 71 +/- 5 microm) interfaces were smaller than Cercon interfaces (B2, 129 +/- 38 microm); internally, B1 (80 +/- 11 microm) interfaces were smaller than B2 interfaces (130 +/- 12 microm). CAD/CAM produced better marginal and internal accuracy of fit compared to slip casting and CAM techniques.

Strength and fracture pattern of monolithic CAD/CAM-generated posterior crowns.

OBJECTIVES: This study evaluated the strength and fracture pattern of monolithic posterior CAD/CAM crowns hypothesizing that zinc-phosphate cemented lithium disilicate crowns might show the same fracture strength as adhesively cemented crowns. METHODS: Two sets of monolithic posterior crowns each with uniform occlusal and lateral wall thickness of 1.5mm were fabricated from three types of block ceramic (1) lithium disilicate glass, (2) leucite glass and (3) feldspathic ceramic using CEREC 3 CAD/CAM. Crowns (n = 15) of ceramics (1), (2) and (3) each were (A) zinc-phosphate cemented, (B) adhesively cemented on resin-based composite dies and loaded until fracture. Load data was analyzed using ANOVA and Scheffé tests. Crack pattern was evaluated on an additional three sample cross-sections for each group at start of fracture. RESULTS: Radial cracks originated early at the cementation interfaces and cone cracks were observed finally at the loading sites. Mean load values (SD) of A-crowns at fracture start/end (1) 807 (91) N/2082 (192) N; (2) 915 (193) N/1130 (166) N; (3) 985 (199) N/1270 (301) N were all significantly (P < 0.001) lower when compared to their B-crown analogs (1) 1456 (205) N/2389 (84) N; (2) 1684 (395) N/2469 (171) N; (3) 1548 (304) N/2392 (75) N, rejecting the authors hypothesis. A-1 crowns had significantly (P < 0.001) higher fracture load than A-2 and A-3 crowns. The A-1 crown fracture load data, even if significantly (P < 0.001) lower, came close to the B-1 values. SIGNIFICANCE: Adhesive cementation balanced the strength of weak ceramics with that of strong ceramic and recommended itself for leucite glass ceramic and feldspathic ceramic crowns. Zinc-phosphate cementation appeared feasible for lithium disilicate crowns.

The bonding area of intra- and extra-coronal tooth preparations.

PURPOSE: To assess the accuracy of preparation surface area measurements (mm2) using the Cerec digital mouth camera in vitro and to analyze a collection of 514 Cerec camera in vivo optical impressions of preparations from 274 patients according to the size of preparation/bonding area (mm2) METHODS: The surface area (mm2) of model preparations with known dimensions namely of one occlusal (1) and one mesio-occluso-distal (2) cavity as well as of one central incisor (3) and one molar (4) crown preparation was calculated from linear (a) design dimensions, (b) slide-gauge and (c) coordinate-measuring-machine data as benchmark measurements and from repeated (n=10) (d) laser-scan (control), (e) Cerec-camera mounted on a support, (f) handheld Cerec-camera measurements. Data of (d), (e) and (f) was statistically analyzed. From a collection of data sets clinically recorded with the Cerec camera, the surface areas of 514 preparations from 274 patients were analyzed according to the type of tooth and type of preparation. RESULTS: Occlusal cavity mm2 data 1(d) 48 +/- 0.4, 1(e) 48 +/- 0.2, 1(f) 48 +/- 0.6 and mod cavity mm2 data 2(d) 137 +/- 2, 2(e) 138 +/- 1, 2(f) 138 +/- 4 did not differ between (d), (e) and (f) (P> 0.05) confirming the hypothesis for inlay cavities. Incisor crown preparation mm2 data 3(d) 82+0.4 differed (P< 0.001) from 3(e) 85 +/- 0.2 and 3(f) 85 +/- 0.6 as well as molar crown preparation mm2 data 4(d) 133 +/- 0.6 differed by 3.5% (P< 0.001) from 4(e) 137 +/- 0.4 and 4f) 138 +/- 1. Clinical cavity and crown preparation area data obtained from in vivo Cerec camera recordings differentiated between type of tooth and type of cavity. 2D data of "classic", "reduced" and "endo" type crown preparations did not differentiate clearly.

Clinical prospective evaluation of zirconia-based three-unit posterior fixed dental prostheses: Up-to ten-year results.

OBJECTIVES: Only a few studies exist, which assess the clinical long-term behavior of all-ceramic FDPs in the posterior region. The aim of the present prospective clinical study was to evaluate the clinical performance of posterior three-unit FDPs manufactured from Y-TZP after a service period up to 10 years. METHODS: 55 patients received 59 three-unit FDPs in the posterior region of the maxilla or mandible. Abutment teeth were prepared and full-arch impressions were taken. Definitive casts were fabricated and optically scanned. Frameworks were fabricated with computer-aided design (CAD) and manufacturing (CAM) technology. Y-TZP frameworks were veneered and adhesively luted to the abutment teeth. Baseline and follow-up examinations (service time: ≥ 48 months) were recorded by applying modified United States Public Health Services (USPHS) rating criteria. Cumulative survival rate was analyzed with Kaplan-Meier. Percentage of biological and technical complication was calculated. RESULTS: Fifty-three patients with 57 FDPs attended the last follow-up visit and a mean observation period of the remaining was 6.3 ± 1.9 years was calculated. Biological complications occurred in 17.5%, technical complications in 28% of the FDPs. The 10-year cumulative survival rate amounted 85.0%. Three FDPs failed to survive, two due to a root fracture of the abutment tooth and one due to secondary caries. CONCLUSIONS: Three-unit FDPs made from Y-TZP, veneered with ceramic offer a treatment option with a high rate of chipping. However, the manufacturing processes nowadays are modified in order to avoid this complication. CLINICAL SIGNIFICANCE: The results of the present investigation suggest that three-unit Y-TZP posterior FDPs may are a possible treatment option. However, a high rate of chipping can be expected.

Effect of ozone on enamel and dentin bond strength.

PURPOSE: To evaluate the influence of direct high-dose gaseous ozone application (2100 ppm) on dentin and enamel shear bond strength. MATERIALS AND METHODS: Ten bovine enamel and dentin samples per group were pretreated as follows: (I) ozone application (Healozone, KaVo) for 60 s alone or (II) with subsequent application of a fluoride- and xylitol-containing antioxidant (liquid reductant), (III) light-activated bleaching with 35% hydrogen peroxide for 5 min serving as negative control (Hi-Lite, Shofu), and (IV) untreated enamel and dentin (positive control). Specimens were bonded with a functional 3-step adhesive system (Syntac Classic, Ivoclar Vivadent) and restored with a composite (Tetric Ceram, Ivoclar Vivadent) according to the Ultradent method. After storage in water at 37 degrees C for 24 h, shear bond strength was measured using a Zwick universal testing machine. Data were analyzed using ANOVA and Scheffe's post hoc analysis. RESULTS: In concordance with the existing literature, bleaching resulted in significantly decreased bond strength (p < 0.05) on enamel specimens. No decrease in shear bond strength was detected for ozone-pretreated specimens compared to untreated controls. CONCLUSION: Despite a possible retention of surface and subsurface oxide-related substances during high-dose ozone application, shear bond strength was not impaired. Thus, adhesive restoration placement should be possible immediately after ozone application for cavity disinfection.

Three-unit posterior zirconia-ceramic fixed dental prostheses (FDPs) veneered with layered and milled (CAD-on) veneering ceramics: 1-year follow-up of a randomized controlled clinical trial.

OBJECTIVE: The aim of this multicenter randomized controlled clinical trial was to test posterior zirconia-ceramic fixed dental prostheses (FDPs) veneered with a computer-aided design/computer- assisted manufacture (CAD/CAM) lithium disilicate veneering ceramic (CAD-on) and manually layered zirconia veneering ceramic with respect to survival of the FDPs, and technical and biologic outcomes. METHOD AND MATERIALS: Sixty patients in need of one posterior three-unit FDP were included. The zirconia frameworks were produced with a CAD/CAM system (Cerec inLab 3D/Cerec inEOS inLab). Thirty FDPs were veneered with a CAD/CAM lithium disilicate veneering ceramic (Cad-on) (test) and 30 were veneered with a layered zirconia veneering ceramic (control). For the clinical evaluation at baseline, 6, and 12 months, the United States Public Health Service (USPHS) criteria were used. The biologic outcome was judged by comparing the plaque control record (PCR), bleeding on probing (BOP), and probing pocket depth (PPD). Data were statistically analyzed. RESULTS: Fifty-six patients were examined at a mean follow-up of 13.9 months. At the 1-year follow-up the survival rate was 100% in the test and in the control group. No significant differences of the technical outcomes occurred. Major chipping occurred in the control group (n = 3) and predominantly minor chipping in the test group (minor n = 2, major n = 1). No biologic problems or differences were found. CONCLUSIONS: Both types of zirconia-ceramic FDPs exhibited very good clinical outcomes without differences between groups. Chipping occurred in both types of FDPs at small amounts, yet the extension of the chippings differed. The test FDPs predominantly exhibited minor chipping, the control FDPs major chipping.