Surgical templates for prosthetically guided implant placement

Reliability of a chairside CAD-CAM surgical guide for dental implant surgery on the anterior maxilla: An in vitro study

PURPOSE

This study evaluated the reliability of the chair-side CAD-CAM surgical guide (CSG) in the anterior maxilla by comparing its accuracy with the laboratory 3D-printed surgical guide (3DSG) and manual surgical guide (MSG) concerning different levels of dentists' surgical experience.

MATERIALS AND METHODS

Ten surgical guides of each type (MSG, 3DSG, and CSG) were fabricated on a control study model with missing right and left central incisors. Sixty implants were placed in 30 study models by two dentists (one inexperienced and one experienced) using three different types of surgical guides. Horizontal deviations at shoulder and at apex, vertical, and angular deviations were measured after superimposing the planned and placed implant positions in the software. Kruskal-Wallis and Mann-Whitney U tests were used to compare the accuracy of three types of surgical guides in each dentist group and the accuracy of each surgical guide between two dentists (α = .05).

RESULTS

There were no significant differences in any deviations between CSG and 3DSG, apart from angular deviation, for both dentists' groups. Moreover, both CSG and 3DSG showed no significant differences in accuracy between the two dentists (P > .05). In contrast, MSG demonstrated significant differences from CSG and 3DSG and a significant difference in accuracy between the two dentists (P < .05).

CONCLUSION

CSG provides superior accuracy to MSG in implant placement in the maxillary anterior region and is comparable to 3DSG at different levels of surgical experience, while offering the benefits of shorter manufacturing time and reduced patient visits.

A dual scan approach to creating an accurate dental surface for virtual implant planning: A dental technique

Artifacts from metal restorations can make it challenging or impossible to accurately orient a digital dental cast to cone beam computed tomography (CBCT) scan data for virtual implant planning. A dual scan technique is described that uses an alginate impression with fiducial markers in a stock tray to create a digital dental cast that is precisely oriented to the scan in the same patient coordinate system for surgical guide design.

The Effects of Distribution of Image Matched Fiducial Markers on Accuracy of Computer-Guided Implant Surgery

PURPOSE

Image registration of the optical intraoral scan to computed tomography image is essential for computer-guided implant surgery. The remaining teeth, which are considered to be congruent structures observed in the scan and radiographic images, are used to perform the image registration. The purpose of this study was to evaluate the effects of the distribution of matching fiducial points on the accuracy of the image registration.

MATERIALS AND METHODS

A partially edentulous model with three anterior remaining teeth was prepared. Two mini dental implants were inserted in the posterior edentulous areas on both sides, and computed tomography and surface scan data were obtained. Three groups were set according to the distribution of the image matching points used: localized distribution, unilateral distribution, and bilateral distribution. Fifteen graduate students performed the registration process in each group using the same image matching method. The accuracy of image registration was evaluated by measuring the geometric discrepancies between the radiographic and registered scan images in the anterior, middle, and posterior regions. One-way and two-way analysis of variance with the Tukey HSD post hoc test were used for statistical analysis (α = 0.05) RESULTS: In general, the registration discrepancy was lowest in the bilateral distribution group, followed by the unilateral distribution and localized distribution groups (p< 0.001). In the regional analysis, the registration error tended to increase as the measurement region moved farther from the matching points. The distribution of the matching points and measurement regions had a statistical interaction in the accuracy of image registration.

CONCLUSION

The accuracy of image registration of the surface scan to the computed tomography is affected by the matching point distribution that can be improved by placing artificial markers in the edentulous areas.

Flexible thermoplastic resin to add retention to tooth-supported stereolithographic surgical guides

Surgical guides produced by stereolithography use hard resin. The hard resin prevents seating beyond the height of contour, hence these guides are not intrinsically retentive. By covering the guide with a flexible thermoplastic material that extends into the undercuts, the resulting guide now has a retentive feature. This allows it to maintain its position during surgery yet it can easily be removed and repositioned.

An adjustable, cast based, fully restrictive surgical guide

The 3D Click Guide is a fully restrictive cast-based surgical guide for the placement of dental implants. This in-office system consists of prefabricated parts that are assembled onto a carrier. The 3-dimensional data are derived from a dental cast in combination with a periapical radiograph or cone-beam computed tomography data.

An organized start to implant-supported prosthesis

Various treatment options are available for rehabilitating the complete edentulous patients with implants. However, due consideration for the prosthesis is not given prior to implant surgery. This can result in implant being placed in locations that do not provide the best esthetic and functional result. Incorrect implant localization and angle are the primary cause of non-axial loading and may contribute to loss of Osseo-integration. For predictable outcome, the treatment should begin with visualizing the end result. A step-wise pre-implant surgery evaluation is necessary to achieve the objectives. This is a case report of a completely edentulous patient who was treated with fixed implant prosthesis following various steps in the pre-implant surgery evaluation.

Reliability of implant surgical guides based on soft-tissue models

The purpose of this study was to determine the accuracy of implant surgical guides fabricated on diagnostic casts. Guides were fabricated with radiopaque rods representing implant positions. Cone beam computerized tomograms were taken with guides in place. Accuracy was evaluated using software to simulate implant placement. Twenty-two sites (47%) were considered accurate (13 of 24 maxillary and 9 of 23 mandibular sites). Soft-tissue models do not always provide sufficient accuracy for fabricating implant surgical guides.

Soft-Tissue Healing and Impression Technique in Implant Dentistry: A Case Report

The present clinical report describes a technique for aesthetic restoration of single dental implants in the anterior area. One objective of implant therapy in anterior areas is the achievement of an aesthetic result, which is highly dependent on the condition of the peri-implant soft tissue. A 22-year-old woman presented with right maxillary lateral incisor agenesis. An implant was placed, and a transfer impression technique carried out. The model was used to construct the custom abutment, provisional crown, and metal substructure. The metal substructure was covered with a waxed collar with the same emergence profile as the provisional restoration. The abutment and the provisional crown were placed, and after soft-tissue healing, an impression was taken using the waxed metal framework as coping. This final impression also registered and transferred the architecture of the soft peri-implant tissues. This clinical report describes an impression technique that accurately duplicates the peri-implant tissue profile. The final prosthesis is therefore shaped according to the interim prosthesis, for ideal contour and soft-tissue position. This technical procedure requires minimal chair time and is cost effective, as fewer components are used during the treatment.

Use of diagnostic and surgical stent: a simplified approach for implant placement

Dental implantology has emerged as a practical alternative to traditional prosthodontics. Since the beginning, placement of implant in the bone to achieve a prosthetic solution that fulfils biologic, aesthetic and biomechanical requirements has been a challenge. In the past, implant site and inclination were dictated by residual bone quality. The desire for predictable prosthesis led to the development of prosthetically guided implantology. This concept establishes the correct implant position during the diagnostic stage according to planned definitive restoration. In prosthetically guided implantology where ideal placement of implant is determined by the definitive restoration, use of radiographic and surgical stent in conjunction with dental CT scan can play an important role. A stent is an appliance used for radiographic evaluation during treatment planning for implant placement and during surgical procedures to locate optimal implant placement site. The stent with dental CT scan enables the dental team to identify specific sites of prospective implant surgery and hence determines the optimal position and angulation of implant relative to occlusal load. Aided by stent the surgeon can avoid undesirable implant site preparation and minimize unnecessary osteotomy, resulting in favorable design of prosthesis, reduced surgical trauma, reduced surgical time and increased patient comfort. This case report is an insight into the method of fabrication of simple and cost effective stent for implant placement and its advantages over the other techniques of stent fabrication.

Flapless implant placement with crown lengthening procedure to correct crown height: a case report

Bone loss and soft tissue loss are common problems after tooth extraction and that can lead to excessive length of clinical crowns. This problem can be exacerbated by delaying implant placement after tooth extraction. In this case the opposite occurred. After flapless placement of a NobelDirect implant with immediate loading there was not enough vertical space for an esthetic restoration. Surgical crown lengthening was performed to create vertical space to place an esthetically pleasing restoration in harmony with the patient's existing dentition.

Cast-based guided implant placement: a novel technique

One of the most challenging aspects of implant placement is the correct spatial positioning of the dental implant in the bone. Surgical guides of various configurations have been proposed to aid implant placement. If a fully limiting surgical guide is used, the encoded information should be reliable, as deviations are not possible during surgery. This article describes a combination of analog techniques, including bone sounding and periapical radiographs used to study the available bone volume. A simplified casting protocol is proposed, and the implant platform position of the implant analog is transferred to a surgical guide composed of a stiff vinyl polysiloxane material. This surgical guide is used in a conventional flapless guided implant surgery protocol. This combination of techniques allows precise placement of a dental implant, abutment, and provisional restoration in a minimally invasive manner.

Screw versus cemented implant supported restorations

Implant supported restorations can be attached to implants with screws or can be cemented to abutments which are secured to implants with screws. Screw retained implant restorations are the authors' preferred method of securing restorations to implants. This article will be written from this perspective and the advantages and disadvantages of each method of retention will be discussed under the following headings: Aesthetics, Retrievability, Retention, Implant placement, Passivity, Provisionals, Occlusion, Immediate loading, Impression procedures, Long term treatment planning.