Use of Implant‐Supported Custom Milled Impression Copings to Capture Soft‐Tissue Contours and Incisal Guidance

A technique is presented where a custom milled impression coping is used to replicate the clinically established anterior incisal guidance to the definitive prosthesis when multiple implants are restored in the esthetic zone. A conventional impression is initially made, then the stone cast is scanned, and a digitally designed custom screw‐retained, implant‐supported interim prosthesis is milled from a polymethylmethacrylate (PMMA) billet. This is aimed to digitally design the pontic areas, contour the gingival soft tissue, and establish an anterior incisal guidance. A custom milled impression coping (CMIC) is then fabricated. The CMIC has contours similar to the contours of the interim prosthesis and is fabricated from a PMMA billet. Titanium inserts are placed in the interim prosthesis and the CMIC. The CMIC is inserted intraorally and used for the final impression by using a custom tray and by following the open tray impression protocol. With the proposed technique, the exact contours of the digitally designed and clinically verified interim prosthesis are used to fabricate the definitive restoration.     

Precise Reproduction of Soft Tissue Structure around the Pontic Area Using Computer‐Aided Design and Manufacturing

Reproducing soft tissue contours around a pontic area is important for the fabrication of an esthetic prosthesis, especially in the anterior area. A gingival model that precisely replicates the soft tissue structure around the pontic area can be easily obtained by taking a pick‐up impression of an interim fixed dental prosthesis. After a working cast is fabricated using the customary technique, the pick‐up model is superimposed onto the working model for the pontic area using computer‐aided design and manufacturing (CAD/CAM). A definitive restoration using this technique would be well adapted to the pontic base, which is formed by the interim prosthesis.     

A laboratory investigation of the accuracy of two impression techniques for single-tooth implants

PURPOSE: This laboratory study investigated the accuracy of four implant impression procedures using two impression techniques and two different materials. MATERIALS AND METHODS: A master model was used to produce 40 different stone casts incorporating laboratory implant or abutment analogues from the different combinations of two impression techniques (the repositioning impression coping technique at the implant level and the pickup impression technique at the abutment level) and materials (President polyvinyl siloxane and Impregum F polyether). Variations in the resulting working casts were measured using the Reflex Microscope to derive distances and angles from the three-dimensional coordinates of optical targets that were attached to a test coping placed on the implant analogue and on a reference device positioned on the occlusal surfaces of the casts. RESULTS: The results showed greater variations in analogue position with the repositioning impression technique than with the pickup technique. The rotational errors were large enough to be of clinical concern. No significant differences were found between polyvinyl siloxane and polyether impression materials for the two tested types of impression techniques. CONCLUSION: The repositioning impression technique at the implant level can produce less predictable results than the pickup technique at the abutment level. The choice of impression material made no significant difference.     

Implant Digital Impression in the Esthetic Area

The aim of this report is to describe two standardized protocols for digital impression when implant support rehabilitation is used in the esthetic area. The two techniques were used to transfer all provisional crown parameters to definitive restorations in different clinical scenarios. In the direct technique, an impression (STL1) is made of the provisional restorations attached to the implants, with surrounding gingival tissue. The second scan (STL2) captures the sulcular aspect of the peri‐implant soft tissue immediately after removal of the provisional restoration. The last impression (STL3) of the complete arch is made with a standardized scanbody attached to the implant to capture the 3D location of the implant. The direct technique is indicated when the peri‐implant soft tissues are stable upon removal of the provisional restoration. The indirect technique is used when the gingival tissue collapses rapidly after the removal of the provisional crown. The impressions of the provisional restoration and the position of the implant are similar to those obtained with the direct technique, and the shape of the peri‐implant tissue is extrapolated from the negative shape obtained from making the digital impression when the provisional restoration is taken out of the mouth. Finally, in both techniques the 3 scans are superimposed to obtain a file, which contains the details of the peri‐implant soft tissue. The direct and indirect digital techniques allowed realization of a predictable definitive restoration in the esthetic zone in different clinical scenarios, reducing the duration of clinical procedures.     

A digital implant custom tray fabrication method using the design process for simulating the position of the impression copings and 3D printing technology

The technique described allowed an implant custom tray to be fabricated referencing the location of connected impression copings. The technique uses dental computer-aided design (CAD) software and 3D printing technology. The method controls the thickness of the impression material around the impression copings, improving the impression-making process.     

Evaluation of Accuracy of Direct Transfer Snapon Impression Coping Closed Tray Impression Technique and Direct Transfer Open Tray Impression Technique: An In Vitro Study

Accuracy of the implant impression technique is one of the key factor determining the strain free fit of the prosthesis fabricated which influences the treatment success. Two implant impression techniques namely the closed tray technique with transfer coping and open tray technique were evaluated for accuracy with stone casts obtained from them. Casts were evaluated using a custom constructed bar on strain gage (SYSCOM) and abutment coordinates using Coordinate Measuring Machine (TESA micro-HITE). The statistical analysis with one way ANOVA and Mann–Whitney tests show that the casts obtained with open tray technique were accurate than the casts of closed tray technique (significance P < 0.001). Direct transfer impression technique with less number of components ensures the high accuracy of transfer of implant positions from master cast to the laboratory cast compared to the indirect transfer impression technique.     

The O‐Ring Universal Impression Technique

Recording the implant position for master cast fabrication for multiple implant systems may require a large inventory of impression copings. A technique is described whereby implant impression‐making procedures can be modified to be more universal to all implant systems. This makes the procedure more cost‐effective by simply incorporating the use of a rubber O‐ring on the abutment or fixture mount, which then eliminates the use of a transfer coping. This technique can be applied at the time of surgery for indexing as well as during the final impression appointment.     

A laboratory investigation of the accuracy of the repositioning impression coping technique at the implant level for single-tooth implants

This study investigated the accuracy of the repositioning impression technique at the implant level using vinyl polysiloxane impression material. Three groups each of ten senior dentists, postgraduate students and technicians were asked to use this technique to record the position of an implant in a master model. The Reflex Microscope was used to measure variations between the resulting casts and the master model. Significant difference between the casts and the master model in the X and Y-axes (p < 0.01) was recorded. Alarming inclinational and rotational errors for the implant analogue position were measured with all groups of operators. Similar distortion in the Z-axis was recorded.     

Nonlinear finite element analysis of a splinted implant with various connectors and occlusal forces

PURPOSE: The aim of this study was to analyze the biomechanics in an implant/tooth-supported system under different occlusal forces with rigid and nonrigid connectors by adopting a nonlinear finite element (FE) approach. MATERIALS AND METHODS: A model containing 1 Frialit-2 implant (placed in the second molar position) splinted to the mandibular second premolar was constructed. Nonlinear contact elements were used to simulate a realistic interface fixation between the implant body and abutment screw and the sliding keyway stress-breaker function. Stress distributions in the splinting system with rigid and nonrigid connectors were observed when vertical forces were applied to the tooth, pontic, implant abutment, or complete prosthesis in 10 simulated models. RESULTS: The displacement obtained from the natural tooth increased 11 times than that of the implant, and the peak stress values within the implant system (sigmaI, max) increased significantly when vertical forces acted only on the premolar of a fixed prosthesis with a rigid connector. The sigmaI, max values seen in the splinting prosthesis were not significantly different when vertical forces (50 N) were applied to the pontic, molar (implant) only, or the entire prosthesis, respectively, regardless of whether rigid or nonrigid connectors were used. Moreover, the peak stress values in the implant system and prosthesis were significantly reduced in single- or multiple-contact situations once vertical forces on the pontic were decreased. DISCUSSION: The compensatory mechanism between the implant components and keyway sliding function of the implant/tooth-supported prosthesis could be realistically simulated using nonlinear contact FE analysis. The nonrigid connector (keyway device) significantly exploited its function only when the splinting system received light occlusal forces. CONCLUSION: Minimization of the occlusal loading force on the pontic area through occlusal adjustment procedures to redistribute stress within the implant system in the maximum intercuspation position for an implant/tooth-supported prosthesis is recommended.     

An In Vitro Study to Compare the Accuracy of the Master Cast Fabricated by Four Different Transfer Impression Techniques for Single-Tooth Implant Replacement

Single tooth implant retained crowns have become a recognized technique for the replacement of the missing teeth. With the predictable integration of implants, the emphasis is shifted towards precise prosthesis. Minor movement of the impression coping retained inside the impression material can occur during all the procedures, leading to the three-dimensional spatial inaccuracies in the master casts. Therefore, the present study was undertaken with the purpose to evaluate the accuracy of single-tooth implant impression techniques using four different impression copings, so as to obtain a precise definitive cast for a single-unit implant restoration. A maxillary acrylic resin model with a standard single implant in the first molar region was used to simulate a clinical situation. A total of 60 impressions were made with polyvinylsiloxane impression material, which were divided into four groups of 15 impressions each. Group I used non-modified square impression coping, while in group II, III and IV square impression coping were modified differently. Master casts fabricated for all the groups were analyzed to detect rotational position change of the hexagon on the implant replicas in the master casts in reference to the resin model. The master casts obtained with the roughened and adhesive-coated impression copings showed a lower amount of rotational movement than the masters casts achieved with the non-modified impression copings. Hence, the clinician should use sandblasted and adhesive coated impression copings to achieve a more accurate and precise orientation of the implant replicas in the laboratory master casts in single-tooth implant restorations.     

An evaluation of three implant level impression techniques for single tooth implant

This laboratory study investigated the hypotheses that there is no difference between three implant level impression techniques using vinyl polysiloxane impression material. The tested techniques were 1)- the repositioning technique. 2)-The pickup technique. 3)- The pickup technique with the impression copings splinted to the impression trays with autopolymerising acrylic resin. The Reflex Microscope was used for 3D measurement of distances and angles. Analysis of variance and Tukey's multiple comparisons test were applied to analyse the data. The results showed significant differences in implant analogue position with the repositioning and the pickup (unsplinted) impression techniques from the master model. Alarming rotational errors were recorded with the repositioning and the pickup (unsplinted) techniques. However, connecting the impression coping to the impression tray improves the accuracy of the pickup impression technique.     

A Technique to Simultaneously Fabricate Multiple Custom Impression Posts for Implant‐Supported Restorations in the Esthetic Zone

Peri‐implant transmucosal tissue, an essential element of peri‐implant esthetics, is critical to the success of prostheses in the esthetic zone. The optimal transmucosal tissue profile can be transferred to the master cast with the aid of custom impression posts. In this clinical technique, the initial cast used to fabricate provisional prostheses was conveniently used to aid in the time‐efficient fabrication of multiple custom impression posts simultaneously using self‐cured acrylic resin. This technique also applies to single restorations. In addition, the use of an initial cast as holder makes it easy to transfer custom impression posts to the mouth accurately and efficiently.     

Accuracy of two impression techniques with angulated implants

STATEMENT OF PROBLEM: Accurate recording of implant locations is required so that definitive restorations are properly supported and do not place additional stress on the implants. Angulated implants may result in inaccurate impressions, and the impression technique may affect the accuracy of the definitive cast. PURPOSE: The purpose of this study was to determine the effect the combined interaction of impression technique, implant angulation, and implant number has on the accuracy of implant definitive casts. MATERIAL AND METHODS: One definitive stone cast was fabricated for each of 6 experimental groups and 1 control group. All 7 definitive casts had 3 implants arranged in a triangular pattern creating a plane. In the 6 experimental groups, the center implant was perpendicular to the plane of the cast while the outer implants had 5, 10, or 15 degrees convergence towards or divergence away from the center implant. The control definitive cast had all 3 implants parallel to each another and perpendicular to the plane of the cast. Five open tray and 5 closed tray addition silicone impressions were made of each definitive cast. Impressions were poured with type IV dental stone, and a fine tip measuring stylus was used to record multiple axis (X-Y-Z) coordinates on the top surface of the implant hex and on the cast base. Computer software was used to align the data sets and vector calculations determined the difference in degrees between the implant angles in the definitive cast and the duplicate casts. Statistical analysis used repeated-measures ANOVA (alpha=.05) with post-hoc tests of significant interactions. RESULTS: The angle errors for the closed and open tray impression techniques did not differ significantly (P=.22). Implant angulations and implant numbers differed in average angle errors but not in any easily interpreted pattern (P<.001). The combined interaction of impression technique, implant angulation, and implant number had no effect on the accuracy of the duplicate casts compared to the definitive casts (P=.19). CONCLUSIONS: The average angle errors for the closed and open tray impression techniques did not differ significantly. There was no interpretable pattern of average angle errors in terms of implant angulation and implant number. The magnitude of distortion was similar for all combinations of impression technique, implant angulation, and implant number.     

Comparative analysis of direct and indirect implant impression techniques an in vitro study. An in vitro study

Implant impression and transfer of the implant position to a working cast for rehabilitative purposes not always represent a predictable reconstructive step. The variable results depend on the transfer technique utilized and on the accuracy of the impression materials. The aim of this study was to compare the accuracy of the direct and indirect impression techniques and to analyze the distortion of different impression materials. An edentulous acrylic resin mandible was used as reference model: in the cuspid position 2 laboratory analogs were inserted perpendicularly to the occlusal plane and fastened with resin. Two impressions for each indirect and direct recording techniques with 4 different impression materials were made. Polyvinyl siloxanes were used for the repositioning implant level method. Polyethers were used for the 'pick up' impression technique. Analysis of cast distortion was measured computing the inter-implant position on the developed models compared to that of the master model. Measurements were recorded by a digital caliper. The results of this in vitro study demonstrate that the direct impression technique is preferable to the indirect one and that the Impregum polyether impression material is the most precise when used in association with a direct technique.     

Management of interdental papillae loss with forced eruption, immediate implantation, and root-form pontic

BACKGROUND: A 25-year-old Asian woman complained of an unesthetic black triangle between her upper right front teeth. Defective interdental papillae may result from external root resorption, which makes esthetic restoration more difficult. A combined use of forced eruption, immediate implant placement, and a root-form pontic made a successful esthetic and functional restoration. METHODS: The treatment sequences of this patient included short-term forced eruption, subsequent immediate implant placement after tooth extraction, and a provisional root-form pontic restoration. A final prosthesis was completed 6 months later, followed by clinical maintenance. RESULTS: Papillae were augmented by forced eruption. After immediate implantation and root-form pontic placement had been performed, the peri-implant soft and hard tissues were manipulated and maintained in a stable state. CONCLUSIONS: We successfully reconstructed the interdental papillae and replaced the deficient tooth with an immediate implantation. During 2 years of follow-up, the implant and peri-implant structures remained stable and healthy.     

An implant impression technique using a plaster splinting index combined with a silicone impression

This article describes a technique for making implant impressions designed to reduce framework misfit. The 2-stage impression technique combines the use of plaster and a silicone impression material. The method can be used for either completely or partially edentulous patients.     

天然牙-游离端种植牙联合支持固定桥的应力分布

目的 :揭示天然牙—种植体联合支持固定桥不同桥长度的设计时应力分布特点 ,为临床优化设计提供实验力学依据。方法 :采用三维有限元的方法研究三种长度桥体的天然牙—游离端种植牙联合支持固定桥的应力分布。结果 :天然牙—种植牙固定桥应力集中于基牙的颈部 ;种植体颈部骨组织的应力大于天然牙颈部骨组织的应力 ;集中垂直载荷时种植体颈部骨的应力分布较均匀 ;集中斜向载荷时种植体的颊舌侧骨组织有明显的应力集中区 ,并且桥体跨度增加 ,种植体周骨的最大应力值增加 ,天然牙周骨的应力值无显著变化。结论 :天然牙—种植体固定桥受集中斜向载荷易导致种植牙周骨损伤 ,尤其桥体长度增加时应减小侧向力并增加基牙数量     

数字化印模在口腔种植修复中的研究进展

数字化印模是指使用口内扫描仪在患者口内无需直接接触即获取组织图像,并合成三维牙列影像的印模技术。数字化印模于口腔种植修复中的应用近年来开始受到关注,但其印模精度尚不明确,尤其是多颗种植体的数字化印模精度。本文详细介绍数字化印模的原理、在种植修复不同类型牙列缺损或缺失情况下的精度以及影响精度的相关因素,以期为数字化印模在种植修复中的临床应用提供参考依据。     

Fabricating an Accurate Implant Master Cast: A Technique Report

The technique for fabricating an accurate implant master cast following the 12‐week healing period after Teeth in a Day® dental implant surgery is detailed. The clinical, functional, and esthetic details captured during the final master impression are vital to creating an accurate master cast. This technique uses the properties of the all‐acrylic resin interim prosthesis to capture these details. This impression captures the relationship between the remodeled soft tissue and the interim prosthesis. This provides the laboratory technician with an accurate orientation of the implant replicas in the master cast with which a passive fitting restoration can be fabricated.     

Impression technique for partially edentulous patients

This article describes an implant impression technique for partially edentulous patients in which impression plaster and irreversible hydrocolloid are used. The technique ensures accuracy, ease of manipulation, and decreased working time.