Custom Abutments Research Articles

Tissue-level versus bone-level single implants in the anterior area rehabilitated with feather-edge crowns on conical implant abutments: An up to 5-year retrospective study

Statement of problemLimited information is available on the differences between tissue-level implants with an ultrathin threaded microsurface conical transmucosal portion and bone-level implants rehabilitated with conical custom abutments. PurposeThe purpose of this retrospective study was to assess the outcomes of crowns designed as per the biologically oriented preparation technique (BOPT) cemented on conical titanium abutments on tissue-level and bone-level implants. Material and methodsPatients consecutively rehabilitated with a delayed loading protocol with anterior implant-supported single crowns with a feather-edge margin, in function for at least 4 years, were recruited and divided into 2 groups based on the implant type they had received: tissue-level implants with a conical transmucosal portion or bone-level implants rehabilitated with a conical abutment by following the platform switching concept. Bone resorption, pink esthetic score (PES), and white esthetic score (WES) were collected and analyzed. The nonparametric Mann-Whitney test was performed to analyze all parameters (α=.05 for all tests). ResultsA total of 43 participants (48 implants) were included in the present study. The mean follow-up period was 4.5 years (range 52-64 months). A statistically significant difference (P=.004) was found in the mean ±standard deviation bone resorption between tissue-level implants (0.38 ±0.46 mm) and bone-level implants (0.83 ±0.58 mm). Higher values for both PES and WES were obtained in the tissue-level implant group. ConclusionsWithin the limitations of the present retrospective study, tissue-level implants with a conical transmucosal portion seem to provide a suitable alternative to bone-level implants in the anterior area.

Evaluation of Clinical Accuracy of Implant Abutment-Level Impression Technique Using Digital Superimposition of Customized Abutment.

Taking a conventional implant abutment-level impression with the gingival retraction technique can cause side effects such as gingival recession and bleeding. In order to overcome these problems, an impression technique using digital superimposition of the customized abutment is newly introduced. In this technique, digital impression data and pre-scanned abutment data are superimposed to reproduce the abutment's location and shape on computer-aided design software. The present investigation was conducted to evaluate the clinical accuracy of the newly adapted digital superimposition impression technique by assessing the fit of fabricated prostheses. The results showed clinical efficacy of this technique, satisfying both convenience and clinically acceptable marginal and internal fit.

Dental implant-abutment fracture resistance and wear induced by single-unit screw-retained CAD components fabricated by four CAM methods after mechanical cycling

Statement of problemComputer-aided design and computer-aided manufacturing (CAD-CAM) methodologies allow the fabrication of custom dental implant abutments with a variety of materials and techniques. Studies on the mechanical strength of such components and the wear induced at their coupling interface during mechanical cycling are sparse. PurposeThe purpose of this in vitro study was to measure the wear patterns at the hexagonal platform of dental implants induced by the installation and mechanical cycling of custom abutments fabricated by using 4 different CAD-CAM methods and to determine the compressive static resistance of the implant-abutment combinations. Material and methodsA CAD software program was used to design a custom abutment for a single-unit screw-retained external hexagon dental implant crown. The same design file was used to manufacture with 4 CAM methods (N=40): milling and sintering of zirconium dioxide (ZO), cobalt-chromium (Co-Cr) sintered by selective laser melting (SLM), fully sintered machined Co-Cr alloy (MM), and machined and sintered agglutinated Co-Cr alloy powder (AM). Prefabricated titanium abutments were used as a control (TI). Each abutment was installed onto a dental implant (4.1×11 mm), and the specimens were mechanically aged (1 million cycles, 2 Hz, 100N, 37 °C). After mechanical cycling, the hexagonal connection of the dental implants was examined with a scanning electron microscope (SEM), and unused dental implants (NI) were examined as a control (n=10). The images were analyzed with a software program to quantify the areas that showed wear. The implant-abutment combinations were reassembled and submitted to a compression test (1mm/min) with a universal testing machine. The data obtained were submitted to 1-way ANOVA (α=.05). ResultsThe mean ±standard deviation fracture load (N) of the specimens of each group were 1005 ±187 (ZO), 1074 ±123 (SLM), 1033 ±109 (MM), 1019 ±149 (AM), and 923 ±129 (TI). These values were statistically similar (P=.213). The mean ±standard deviation wear of the implants in squared-pixels were 1.1 ±0.38×105 (ZO), 2.0 ±0.29×105 (SLM), 1.0 ±0.38×105 (MM), 1.1 ±0.27×105 (AM), 1.1 ±0.33×105 (TI), and 0.51 ±0.29×105 (NI). The results indicated that, although significantly higher than those in in the control group (NI), the wear values found in the groups TI, ZO, MM, and AM were significantly lower than in the SLM group (P<.001). ConclusionsThe CAD-CAM abutments presented the same mechanical fracture load and wear measurements as the TI group, except for the SLM material, which showed increased wear. The failure mode from the load bearing test was the fracture of the abutments for the ZO group. The implants permanently deformed or fractured for the metal abutment groups.

Effect of computer literacy on the working time of the dental CAD software program.

The purpose of this study was to compare the correlation between the learning effect of dental computer-aided design (CAD) software and computer literacy in the clinical and preclinical experience groups of computer-aided design and computer-aided manufacturing (CAD/CAM). A total of 28 participants were recruited, including 14 dental students and 14 dental technicians. Their working time was evaluated using a custom abutment design with two dental CAD software program (exocad GmbH and Deltanine). The working time of custom abutment design was measured 3 times. A survey was conducted to evaluate the computer literacy. For statistical analysis, Mann-Whitney U test was used to analyze the difference between the clinical and preclinical experience groups and the correlation between computer literacy and reduction in working time was confirmed by Spearman's Rank correlation analysis (α=.05). The median working time showed the clinical experience group had faster than the preclinical experience group (P<.001). On the other hand, the reduction in working time was higher in the preclinical experience group (P=.002). Only preclinical experience group had a significant positive correlation between the computer literacy and reduction in working time (P<.001). Basic computer skills are required for first-time users to achie ve an excellent learning effect of dental CAD software program.

Design concept to facilitate the positioning of a custom abutment on an implant

With the development of computer-aided design and computer-aided manufacturing (CAD-CAM) technology, implant abutments have been fabricated with nearly unlimited design options.1,2 When an implant indexing device has not been fabricated or is not available, additional chair time for placing a custom abutment on a hexagonal connection implant is needed, especially for multiple implant restorations, as the abutment can be positioned in 6 different orientations.3,4 This article describes a design concept for fabricating a custom abutment with a mark.

Influence of Screw Channel Angulation on the Fracture Resistance of Zirconia Abutments: An In Vitro Study.

The aim of this study was to investigate the effect of implant screw channel angulation on the fracture resistance of zirconia abutments without artificial aging. Ten implant replicas were embedded in a jig of autopolymerizing acrylic resin. Using a surveyor and a metallic platform, the implant replicas were mounted centrally and with an angulation of 30°. A maxillary left central incisor crown was fabricated from pattern resin and scanned. The digital design of a monolithic zirconia implant abutment-crown was completed using a 3D imaging software. For all specimens of this group (ASC25 ), the screw channel was positioned at 25° to the lingual. Following fabrication, the samples were attached onto the embedded implant replicas and manually torqued to 35 Ncm as recommended by the manufacturer. The monolithic zirconia implant abutment-crowns were mounted in a metallic platform, positioned perpendicular to the indenter, and subjected to loading until failure. Crosshead speed was set at 0.5 mm/min for the universal testing machine. Data from a similar in vitro study where straight zirconia custom abutments (ASC0 ) were subjected to static load until failure was used as a control group. An unpaired Student's t-test was used to determine if fracture resistance based on load at failure and maximum load in each group were significantly different from each other (ASC25 vs ASC0 ). Statistical significance level was inferred at p ≤ 0.05 RESULTS: Group ASC25 fractured at a mean (SD) load of 215.49 (47.10) N and a mean (SD) maximum load of 420.50 (17.18) N. Group ASC0 fractured at a mean (SD) load of 534.04 (133.77) N and a mean (SD) maximum load of 762.69 (109.59) N. The difference was statistically significant for both mean load and mean maximum load at failure (p ≤ 0.05). The survival rate of 0° zirconia abutments was significantly higher than that of 25° ASC zirconia abutments. Within the limitations of this in vitro study the mean fracture load was significantly higher in the group with a straight channel angulation.

Additive Manufacturing in Dentistry: Current Technologies, Clinical Applications, and Limitations

Purpose of ReviewThis review aimed to illustrate the utility of additive manufacturing technologies for the fabrication of polymer, metal, and ceramic components within the confines of their current and potential clinical applications in dentistry.Recent FindingsThe literature reviewed on five additive manufacturing technologies, namely, vat-polymerization, material jetting, material extrusion, powder-based fusion, and binder jetting, have been investigated in relevance to their dental applications. These technologies have the following existing or potential clinical applications: diagnostic and definitive casts, custom trays, positioning guides for custom abutments, tooth preparation guides, interim dental restorations, all-ceramic crowns, metal crowns and copings, silicone indices, occlusal devices, complete dentures, wax patterns for intra- and extra-coronal restorations, surgical guides, removable partial dentures, and tooth- or implant-supported frameworks.SummaryVat-polymerization, material jetting, and powder-based fusion technologies have existing clinical applications utilizing mainly polymers and metals. Additive manufacturing technologies need further development to be used with ceramic materials for dental applications.

Effect of design parameters of custom abutment on its mechanical property based on orthogonal experiment method

In this paper, the custom abutment with various gingival morphology was designed by CAD software. The finite element analysis (FEA) and orthogonal experiments design L25 (56) were performed to investigate the influence of main design parameters of custom abutment on biomechanical property of implant system, including gingival height (GH), abutment angle (A), lingual height (LH), buccal height (BH), mesial height (MH) and distal height (DH). Results indicated that GH and A are the most important factors affecting the biomechanical performance of implant system, and LH, BH, MH and DH have less effect than others. The influence of custom abutment design parameters on biomechanical performance of implant system can be analyzed explicitly by the orthogonal experiment method, which offers a new method for estimating the mechanical characteristics of custom abutment.

Influence of Abutment Fabrication Method on 3D Fit at the Implant-Abutment Connection.

To three-dimensionally evaluate the internal fit at the implant-abutment interface of abutments fabricated with different workflows using a combination of the silicone replica technique and microcomputed tomography (μCT). Thirty abutments were fabricated to restore internal-connection implants and were divided into three groups according to fabrication method: (1) full digital (abutment machined using CAD/CAM system); (2) Ti-Base (prefabricated standard Ti-Base abutments); and (3) UCLA (UCLA-type abutments) (n = 10/group). Linear and volume measurements were performed to assess the internal misfit using a silicone replica of the implant-abutment interface misfit area, which was three-dimensionally reconstructed after μCT. The internal discrepancies in three different regions of interest (Gapsuperior, Gapmarginal, and Gapcenter) were assessed. Data were statistically evaluated using ANOVA and Tukey test (P < .05). Ti-Base and UCLA abutments presented significantly lower misfit volume (0.49 mm3, 95% CI: ± 0.045 mm3 and 0.48 mm3, 95% CI: ± 0.045 mm3, respectively) and mean internal gap (25.20 μm, 95% CI: ± 3.14 μm and 27.97 μm, 95% CI: ± 3.14 μm, respectively) than the full digital group (0.70 mm3, 95% CI: ± 0.045 mm3; 34.90 μm, 95% CI: ± 3.14 μm) (P < .001), but did not differ from each other (P = .825). While Gapcenter was significantly higher in the full digital group (P < .001), Gapsuperior and Gapmarginal did not demonstrate significant differences among groups. All regions were statistically similar within groups, except for Gapcenter in the full digital group, which exhibited higher mean values compared to the other regions (P = .000). The 3D measurements for quantification of internal discrepancy were strongly associated with the 2D measurements. Ti-Base and UCLA abutments exhibited better internal fit at the implant-abutment interfaces compared to a fully digitalized workflow (CAD/CAM custom abutments).

Mechanical Fatigue Analysis of PEEK as Alternative to Zirconia for Definitive Hybrid Abutments Supporting All-Ceramic Crowns.

The aim of this study was to inspect the mechanical fatigue behavior of an implant-supported restorative system using polyether ether ketone (PEEK) and yttria partially stabilized zirconia polycrystals (YZ) as materials for customized definitive implant-supported hybrid abutments, supporting two types of all-ceramic restorations: translucent zirconia (TZ) and lithium disilicate (LD) monolithic crowns. Forty Morse taper implants were included in epoxy resin. Titanium intermediary abutments were placed, and the specimens were randomly allocated into four groups (n = 10) according to the customized hybrid abutment material (PEEK or YZ) and the monolithic crowns (TZ or LD) representing a maxillary central incisor crown. The specimens were subjected to a mechanical fatigue test (step-stress analysis) by means of an initial 200-N load for 5,000 cycles and subsequent increase of 50 N (step-size) at each 10,000 cycles, until failure occurred. The load at failure and number of cycles until failure were recorded; survival probabilities and specimen displacement were calculated for each step. The failure pattern was evaluated, and the Weibull modulus was obtained for each condition. Fatigue of both types of crowns was not influenced by the abutment material (LD-PEEK = LD-YZ; TZ-PEEK = TZ-YZ). In the PEEK abutment, the values obtained in the LD and TZ crowns showed no statistical difference; however, in the YZ abutment, the TZ crown presented a load at failure value that was statistically higher than that for LD. Failure pattern analysis revealed a higher prevalence of crown fracture for LD groups, while screw/implant platform fractures were shown for TZ groups. YZ and PEEK hybrid abutments promoted similar fatigue levels regardless of the crown materials, TZ crowns promoted a higher fatigue level than LD ones when associated with YZ abutments, and LD crowns promoted a similar fatigue level to TZ ones when associated with PEEK custom abutments. Higher prevalence of crown fractures was shown for LD and screw/implant platform fractures for TZ groups.

Occurrence of cement rests on reverse margin custom abutments versus conventional custom abutments

Occurrence of cement rests on reverse margin custom abutments versus conventional custom abutments

Implant Volume Loss, Misfit, Screw Loosening, and Stress In Custom Titanium and Zirconia Abutments.

The aim of this study was to verify the effect of the implant volume loss, vertical misfit between abutment and prosthetic platform, prosthetic screw loosening torque, and screw stress distribution in titanium and zirconia abutments. Ten CAD/CAM system custom abutments of each material were milled and attached to the titanium implants. The implant volume loss was evaluated by microtomography, the vertical misfit with optical microscopy, and digital torque wrench measured the prosthetic screw loosening. All experimental analyses were performed before and after mechanical cycle (1,000,000 cycles, 100 N/2 Hz). Virtual models of the structures were created for finite element analysis, and the stress on the screw obtained with von Mises procedure. Data were analyzed using an independent t-test, two-way ANOVA for repeated measures, and Tukey's HSD test (a=0.05). There was no significant difference in the implant volume loss for the two abutment materials (p=0.662). Titanium abutments provided higher loosening torque values after mechanical cycling (p<0.001). Lesser marginal misfit was obtained with titanium abutments before and after mechanical cycling (p<0.001). The stress distribution on the screw was similar between abutment materials. In conclusion, CAD/CAM custom titanium abutment reduced the marginal misfit and increased the torque maintenance of prosthetic screws when compared to CAD/CAM custom zirconia abutment.

Qualitative and Semi-Quantitative Assessment of Processing-Related Surface Contamination of One- and Two-Piece CAD/CAM Abutments before and after Ultrasonic Cleaning.

Manufacturing processes of custom implant abutments may contaminate their surfaces with micro wear deposits and generic pollutants. Such particulate debris, if not removed, might be detrimental and provoke inflammatory reactions in peri-implant tissues. Although regulatory guidelines for adequate cleaning, disinfection, or sterilization exist, there does not appear to be a consistent application and data on the amount and extent of such contaminants is lacking. The aim of the present in vitro study was to evaluate the quality and quantity of processing-related surface contamination of computer-aided design/computer-aided manufacturing (CAD/CAM) abutments in the state of delivery and after ultrasonic cleaning. A total of 28 CAD/CAM monotype and hybrid abutments were cleaned and disinfected applying a three-stage ultrasonic protocol (Finevo protocol). Before and after cleaning, the chemical composition and the contamination of the abutments were assessed using scanning electron microscopy (SEM), dispersive X-ray spectroscopy (EDX), and computer-aided planimetric measurement (CAPM). In the delivery condition, monotype abutments showed a significantly higher amount of debris compared to hybrid abutments (4.86 ± 6.10% vs. 0.03 ± 0.03%, p < 0.001). The polishing process applied in the laboratory after bonding the hybrid abutment components reduces the surface roughness and thus contributes substantially to their purity. The extent of contamination caused by computer-aided manufacturing of custom abutments can be substantially minimized using a three-stage ultrasonic protocol.

Full Digital Workflow for Anterior Immediate Implants Using Custom Abutments

The full digital workflow involves the combination of intraoral and cone beam computerized tomography scans. In the present case report, a second intraoral scan is performed after soft tissue management facilitated by the use of a 3-dimensional-printed interim implant restoration. The new STL file resulting from the second intraoral scan can be associated with the previous STL from the initial intraoral scan. The custom abutment was also digitally designed as an STL file, and no implant scan bodies were required for intraoral scanning.

Severely angled implant with custom abutment and a screw retained prosthesis: A case report

Edentulousness is one of the human disabilities. Dental implants have increased the quality of life as it restores both function and aesthetics. Due to anatomic challenges, implants can be placed with inclinations and angled abutments can be used. This articles presents a case report of management of mandibular anterior missing tooth with the placement of angled implant using custom abutment along with screw retained prosthesis. Keywords: Dental implant, Surgery, Custom abutment, Fixed prosthesis.

An in vitro investigation comparing methods of minimizing excess luting agent for cement-retained implant-supported fixed partial dentures

Statement of problemThe use of cement-retained implant-supported prostheses is a well-established treatment option. Techniques have been proposed to reduce the amount of residual excess cement (REC) around cement-retained single-implant restorations. However, studies evaluating the effectiveness of such techniques related to cement-retained implant-supported fixed partial dentures (CRISFPDs) are lacking. PurposeThe purpose of this in vitro study was to evaluate the effectiveness of various cement application techniques for CRISFPDs. Material and methodsTwo implant analogs were placed in the lateral incisor sites in a maxillary, 3D printed cast with 4 missing incisors. Twenty standardized, removable, printed soft-tissue replicas, 40 milled titanium custom abutments, and 20 milled zirconia CRISFPDs were fabricated. Two cement application techniques, the brush on technique (BOT), and the polyvinyl siloxane index (PI) technique were compared. Two cementation techniques, without bib (control) (n=10) and with a polytetrafluoroethylene (PTFE) bib (test) (n=10), were used. A premeasured amount of interim cement was used to cement the CRISFPDs. The CRISFPDs were retrieved after cementation, and standardized photographs of 4 quadrants of each abutment-CRISFPD assembly were made by using a software program that is used to calculate the ratio between the area covered with REC and the total specimen area. The extension of the REC on both the abutment and soft-tissue replica was measured at sites before and after cleaning the REC. A generalized linear mixed-model procedure was used for statistical analysis (α=.05). ResultsFor cement application, the polyvinyl siloxane (PVS) index technique had significantly less REC than the brush on technique (P<.05). The use of a PTFE bib led to significantly less REC than when no bib was used (P<.05). ConclusionsThe use of the PVS index technique along with a PTFE bib was effective in reducing REC for CRISFPDs.

Internal and marginal discrepancies associated with stereolithography (SLA) additively manufactured zirconia crowns

Statement of problemStereolithography (SLA) additive manufacturing (AM) technologies can be selected to fabricate zirconia crowns; however, the internal and marginal discrepancies associated with these new technologies remain unclear. PurposeThe purpose of this in vitro study was to measure and compare the marginal and internal discrepancies of milled and AM zirconia crowns by using the silicone replica technique. Material and methodsAn implant custom abutment was manufactured and scanned by using a laboratory scanner (CARES Software; Institut Straumann AG). An anatomic contour crown was digitally designed, and the standard tessellation language (STLC) file was obtained. The STLC file was splinted into 2 pieces, simulating the parts of the crown that would replace the enamel (STLG1 file) and dentin (STLG2 file) structures. Three groups were determined: anatomic contour zirconia milled (CNC group), AM anatomic contour zirconia (AM group), and AM splinted zirconia (SAM group). For the CNC group, the STLC file was used to manufacture milled (CARES zirconium-dioxide crown; Institut Straumann AG) zirconia specimens. For the AM group, the STLC file was used to additively fabricate (CERAMAKER 900; 3DCeram Co) the zirconia (3DMix ZrO2 paste; 3DCeram Co) specimens. For the SAM group, the STLG2 file was selected to AM (CERAMAKER 900; 3DCeram Co) the zirconia (3DMix ZrO2 paste; 3DCeram Co) specimens. Ten specimens per group were manufactured. The silicone replica technique was used to measure the marginal and internal discrepancies. The cement gap was measured on images captured by using a digital microscope at ×100 magnification. For the internal gap, 50 measurements were made for each specimen, and for the marginal gap, 25 measurements were made for each specimen. The normality test, Shapiro-Wilk test, was conducted. The results indicated that the distributions were not normal; therefore, nonparametric Kruskal-Wallis H and pairwise Mann-Whitney U-tests were used to analyze the data. The Spearman correlation coefficient was used to determine the correlation between marginal and internal discrepancies in all 3 groups. ResultsSignificant differences were found in marginal and internal discrepancies among the groups. The CNC group had the least marginal and internal discrepancies compared with the AM and SAM groups. The SAM group had significantly lower values for marginal and internal discrepancies than the AM group. The AM group showed the highest marginal and internal discrepancies. The CNC group had a weak correlation coefficient of 0.13 (P=.046), the AM group had a moderate correlation coefficient of 0.32 (P<.001), and the SAM group had a nonsignificant correlation coefficient of 0.12 (P=.051). ConclusionsCNC and SAM groups had clinically acceptable marginal and internal discrepancies, while the AM group had a clinically unacceptable marginal and internal crown discrepancies. Furthermore, a weak correlation was encountered between the marginal and internal discrepancies measured in all groups.

Cordless digital workflow for scanning implant-supported prostheses at the abutment level: A dental technique

A custom abutment produced from a digital scan can be used to develop an implant-supported prosthesis with ideal contours. A scan body is used to obtain information about the location of the implant fixture, and the scan body has a special scan region that facilitates superimposition. This dental technique indirectly obtains the margin of the definitive prosthesis by designing the special scan region on a custom abutment and superimposing prescanned abutment data onto intraoral scanned data.

The Influence of Progressive Static Load on the Ability of Dental Implants to Withstand Overloading Forces: An Experimental Study in Dogs.

To examine the effect of controlled progressive orthodontic loading on bone around implants subjected to overloading forces. Bilateral edentulous alveolar ridges were created in the posterior maxilla of five beagle dogs and left to heal for an 8-week period, after which 40 implants were placed. In the overloading group (OL), 16 implants were inserted and left to osseointegrate for 16 weeks; impressions were made, and metal crowns were mounted on with supraocclusal contacts with the antagonist teeth. Implants were exposed to dynamic overloading for 16 weeks. In the progressive loading + overloading group (PL+OL), 16 implants were left to osseointegrate for 8 weeks, and custom abutment cores were fabricated and coupled by pairs with Ni-Ti orthodontic springs. Ascending static forces of 100g, 200g, and 300g were each applied for a 3-week period, for a total 9-week progressive loading period. Thereafter, metal crowns with supraocclusal contacts were adapted, and a 16-week overloading protocol for implants was followed as for the overloading group. In the unloaded control group (UL), eight implants were inserted and left uncovered and unloaded for 32 weeks, that is, until the end of the experimental period, at which point all 40 implants were removed with the surrounding bone. Histologic, histomorphometric, and statistical analysis followed. Higher bone-to-implant contact percentage was reported for the OL group (P = .006) and PL+OL group (P < .001) compared with the UL group. Between the OL and PL+OL groups, the addition of progressive loading did not increase the bone-to-implant contact percentage (P = .225). Bone density 1 mm and 2 mm distant to the threads did not differ significantly between the three groups. Significantly lower crestal bone resorption was detected around OL group implants (P = .006) and PL+OL group implants (P = .004) compared with the UL group implants. The implant success rate was 87.5% for the UL group, 67.5% for the OL group, and 87.5% for the PL+OL group. The application of controlled progressive orthodontic loading on osseointegrated implants preceding overloading forces did not increase bone-to-implant contact. When applied, overloading significantly increased bone-to-implant contact compared with the unloaded implants. A significantly higher implant success rate was reported in the PL+OL group compared with the OL group.

Volumetric analyses of restorative crown preparations in simulated-premolar and -molar teeth

Crowns or abutments of fixed partial denture tooth preparations to restore natural teeth or implant-supported restorations require tooth or abutment reduction in a tapered format. Low angulations of axial wall taper to the long axis of the tooth or abutment have been shown to increase the restoration’s stability during masticatory function with large occlusal loads. The tooth preparation and luting agent stabilize the restoration during these loading cycles to prevent dislodgement. Restoration dislodgement represents a catastrophic failure of the prosthesis in function. The preparation attributes contribute to prevent displacement failure and reduce luting agent tensile and shear stresses. Low axial wall taper levels increase resistance to rotational displacement. Increasing axial wall angulations produces negative consequences including reduced rotational resistance, reduced surface area and increased volume of remaining tooth structure. These three considerations have been shown to involve three variables: preparation vertical height, horizontal base width from rotational axis and rotational axis vertical height compared to the opposing axial resisting wall. Natural tooth preparations are completed by a restorative dentist with a hand-held high-speed handpiece with cutting instruments within the oral cavity; while implant-supported custom abutments are prepared in a similar manner but machined outside the oral cavity. As a result, the machined abutment is more controlled for ideal taper in inanimate materials compared to the intraoral tooth preparation on human vital tissues. This experimental study will analyze the preparation of simulated-vital tooth premolars and molars for volume loss at ideal and non-ideal axial wall angulations with variation of vertical heights and vital pulpal tissue volumes.