Evaluating the effects of splinting implant scan bodies intraorally on the trueness of complete arch digital scans: A clinical study.

STATEMENT OF PROBLEM: A predictable protocol for accurately scanning implants in a complete edentulous arch has not been established. PURPOSE: The purpose of this clinical study was to investigate the effect of splinting implant scan bodies intraorally on the accuracy and scan time for digital scans of edentulous arches. MATERIAL AND METHODS: This single center, nonrandomized, clinical trial included a total of 19 arches. Definitive casts with scan bodies were fabricated and scanned with a laboratory scanner as the reference (control) scan. Each participant received 2 intraoral scans, the first with unsplinted scan bodies and the second with resin-splinted scan bodies. The scan time was also recorded for each scan. To compare the accuracy of the scans, the standard tessellation language (STL) files of the 2 scans were superimposed on the control scan, and positional and angular deviations were analyzed by using a 3-dimensional (3D) metrology software program. The Mann-Whitney U test was used to compare the distance and angular deviations between the splinted group and the unsplinted group with the control. The ANOVA test was conducted to examine the effect of the scan technique on trueness (distance deviation and angular deviation) and scan time (α=.05 for all tests). RESULTS: Statistically significant differences were found in the overall 3D positional and angular deviations of the unsplinted and splinted digital scans when compared with the reference scans (P<.05). No statistically significant differences in overall 3-dimensional positional deviations (P=.644) and angular deviations (P=.665) were found between the splinted and unsplinted experimental groups. A faster scan time was found with the splinted group in the maxillary arch. CONCLUSIONS: Conventional complete arch implant impressions were more accurate than digital complete arch implant scans. Splinting implant scan bodies did not significantly affect the trueness of complete arch digital scans, but splinting appeared to reduce the scan time. However, fabricating the splint was not considered in the time measurement.

Scanning accuracy with splinted and unsplinted implant scan bodies for the edentulous arch at implant level: an in vitro study.

Accuracy of completely edentulous arch scanning with implant scan bodies has not been completely validated for intraoral scanners. For desktop laboratory scanners validations were found in the literature. The aim of this in vitro study was to compare the dimensional accuracy of scanning with splinted and unsplinted scan bodies on a completely edentulous maxillary arch with 6 implants. A maxillary edentulous master cast with 6 implants was used as control for all implant level impressions. 6 implants were digitally planned and placed at different angulation of 0, 0  17° and 30°. A contact coordinate measuring machine (CMM) was used to generate baseline linear measurements of the master cast. Four test groups included: 2 intraoral scanners Trios (3shape, Copenhagen, Denmark) and True Definition (3M ESPE, St Paul, MN), one industrial scanner Atos (Core optical 3D scanner) and one conventional impression group scanned with laboratory scanner Dental Wings 7 Series. Each scan recording was made with splinted and unsplinted scan bodies. Digital datasets of all measurements were compared with the CMM baseline values using PolyWorks® InnovMetric Software in order to assess the linear and angular deviations and determine the accuracy of complete arch digital impression. Factorial ANOVA showed significant effect with splinting, scanner type, inter-implant distance and implant angulation for linear deviations. Splinted scan bodies revealed elevated linear and angular deviation values for all scanners with significantly highest deviations for True Definition scanner. Significant correlation was found between inter-implant distance and linear deviation (r =0.45, P =<0.001) with increased linear deviations among all scanners, regardless of splinting. ( P <0.05). Significant effect on accuracy was seen for angular deviation with splinting, scanner type and implant angulation; significant difference was found between 0° and 30° implant angulation ( P =0.035) with more deviation with 30° implant angulation. The accuracy of the complete arch implant digital impression using splinted scan bodies was significantly reduced for measurements that crossed the arch midline. The digital impression technique using a broad splint design to connect scan bodies was not found to improve the scan accuracy for intraoral scanners.

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.

Use of Patient's Own Natural Teeth as Part of the Interim Prosthesis on Immediately Placed Single Implants in a Staged Surgical Approach: A Clinical Report.

A technique is described where the tooth's natural crown is used as part of the interim implant supported prosthesis in clinical situations where a tooth with poor prognosis is extracted and an implant is placed immediately after tooth extraction. A preliminary impression is made before tooth extraction, and the exact tooth positioning is assessed in the laboratory as part of the treatment plan. An acrylic resin repositioning jig is fabricated that will guide the clinician in seating and orienting the crown intraorally after implant placement is completed. After the natural tooth is extracted and an implant is immediately placed via guided approach, the extracted natural crown is hollowed and placed on top of an interim abutment. The natural crown is positioned intraorally by using the acrylic resin repositioning jig. The crown is then internally relined and placed as part of the interim implant supported prosthesis. After osseointegration has been confirmed, a definitive prosthesis is placed.

Digital technology for performing a nasopalatine and greater palatine nerve block with a modified implant surgical guide: A technique article.

This article describes a computer-aided design and computer-aided manufacturing (CAD-CAM) technique to perform a precise nerve block of the nasopalatine and greater palatine nerves by using an implant surgical guide. The technique uses additional guide anchor pins planned and positioned for specific anatomic landmarks during guided implant surgical guide planning. A relief modification virtually designed on the intaglio surface of the surgical guide allows for palatal soft tissue distension following administration of local anesthetic. This information is then transferred to the guide manufacturer to order the modified guided implant surgical guide. The purpose of this procedure is to provide precise delivery of local anesthetic and to prevent any discrepancy in surgical guide seating following injection.

CAD-CAM implant-supported fixed complete dental prosthesis with titanium milled molars: A clinical report.

Implant-supported fixed complete dental prostheses have been associated with a high implant success rate in long-term studies. However, they have also been associated with a high frequency of prosthetic complications. The most frequent and primary prosthetic complication has been the fracture or wear of the occlusal surface of acrylic resin teeth that are typically attached to a metal framework. The design of the framework in this clinical report involved the incorporation of metal occlusal surfaces for the posterior first molars to the framework. The titanium framework was fabricated with computer-aided design and computer-aided manufacturing (CAD-CAM) technology. The remaining teeth were restored in a conventional manner with acrylic resin denture teeth bonded to the titanium framework. This was expected to maintain the occlusal vertical dimension and also reduce the frequency of the primary complications associated with these prostheses.

Digitally planned and fabricated mandibular fixed complete dentures. Part 2. Prosthodontic phase.

Part 1 of this patient report described a prosthetically driven protocol that used computer-aided engineering for the fabrication of a mandibular conversion denture and maxillary provisional complete denture using the AvaDent Digital Denture system. The report demonstrated that this system combined with NobelClinician implant-planning software can be used to efficiently convert a digital denture into an immediately loaded provisional implant-supported fixed complete denture (hybrid prosthesis). Part 2 of the patient report describes the technique and steps involved in the fabrication of a digitally planned and fabricated mandibular fixed complete denture with incorporated titanium milled bar opposed by a definitive computer-aided design/computer-assisted manufacture-milled maxillary complete denture.

Degree of patient pain, complications, and satisfaction after root canal treatment or a single implant: a preliminary prospective investigation.

INTRODUCTION: Dentists often face the choice between tooth retention with root canal treatment and tooth replacement with implant treatment. To date, there has not been a prospective clinical trial directly comparing nonsurgical root canal treatment and single delayed implant therapy with regard to the degree of preoperative and postoperative pain, complications, and patient satisfaction. METHODS: Twenty-four patients had initial nonsurgical root canal treatment, and another 24 had single implant treatment in healed sites. Questionnaires were given at pretreatment, 7 days, 3 months, 6 months, and 12 months. RESULTS: All patients completed the 12-month follow-up period. No significant difference in pain, complications, or overall satisfaction was noted between the 2 groups at any of the time points (P > .05). However, there were differences within each group between the time points. There was more pain at pretreatment for root canal treatment and 7-day post-treatment point for single implant treatment than any other time point. For complications, more were reported at the 7-day post-treatment point than any other time point for both groups. With overall satisfaction, there was no difference from any time point for either group. CONCLUSIONS: The results of this study suggest that patients perceive both treatments with high degrees of satisfaction with minimal pain and discomfort. Differences were found at different time points of treatment and were related to the nature of the treatment itself. This information is useful to help patients with treatment decisions.

Use of a digitally planned and fabricated mandibular complete denture for easy conversion to an immediately loaded provisional fixed complete denture. Part 1. Planning and surgical phase.

This article describes a unique prosthetically driven protocol that uses computeraided engineering to develop sophisticated, scientific algorithms that guide the fabrication of a conversion denture using the AvaDent Digital Denture system (Global Dental Science). This system is combined with Nobel Clinician (Nobel Biocare) implant-planning software to optimize accuracy and to make it easier and faster to convert a denture to an immediately loaded provisional implant supported fixed complete denture following implant placement, using a NobelGuide surgical template.

The incidence of maxillary sinus membrane perforation during endoscopically assessed crestal sinus floor elevation: a pilot study.

Transcrestal sinus membrane elevation is a surgical procedure performed to increase the bone volume in the maxillary sinus cavity. Because of visual limitations, the potential for maxillary sinus membrane perforations may be greater than with the lateral approach technique. The aim of this study was to macroscopically investigate ex vivo the occurrence of sinus membrane perforation during surgery using 3 transcrestal sinus floor elevation methods. Twenty fresh human cadaver heads, with 40 intact sinuses, were used for simultaneous sinus membrane elevation, placement of graft material, and dental implants. Real-time sinus endoscopy, periapical digital radiographs, and cone-beam computerized tomography (CBCT) images were subsequently used to evaluate the outcome of each surgical procedure. Perforation rates for each of the 3 techniques were then compared using a significance level of P < .05. No statistically significant differences in the perforation rate (P = .79) were found among the 3 surgical techniques. Although the sinus endoscope noted a higher frequency of perforations at the time of implant placement as compared with instrumentation or graft insertion, the difference was not statistically significant (P = .04). The CBCT readings were judged to be more accurate for identifying evidence of sinus perforations than the periapical radiographs when compared with the direct visualization with the endoscope. This pilot study demonstrated that a sinus membrane perforation can occur at any time during the sinus lift procedure, independent of the surgical method used.

CAD/CAM fabricated complete dentures: concepts and clinical methods of obtaining required morphological data.

The clinical impression procedures described in this article provide a method of recording the morphology of the intaglio and cameo surfaces of complete denture bases and also identify muscular and phonetic locations for the prosthetic teeth. When the CAD/CAM technology for fabricating complete dentures becomes commercially available, it will be possible to scan the denture base morphology and tooth positions recorded with this technique and import those data into a virtual tooth arrangement program where teeth can be articulated and then export the data to a milling device for the fabrication of the complete dentures. A prototype 3-D tooth arrangement program is described in this article that serves as an example of the type of program than can be used to arrange prosthetic teeth virtually as part of the overall CAD/CAM fabrication of complete dentures.

Lateral and crestal bone planing antrostomy: a simplified surgical procedure to reduce the incidence of membrane perforation during maxillary sinus augmentation procedures.

This clinical report presents a simplified surgical procedure for accessing the maxillary sinus antrum via lateral and crestal approaches, which reduces the potential for sinus membrane perforation and subsequent complications when graft materials and dental implants are placed into the sinus. Due to visual limitations, perforations and associated complications can jeopardize the success rate of the graft and the implants. While there is a lack of clinical data, clinical observations suggest that the procedure, described by the authors as lateral/crestal bone planing antrostomy, can reduce the possibility of perforation of the maxillary sinus membrane during the lateral and crestal approaches to the grafting of the maxillary sinus floor. The technique involves the use of specially designed rotary instruments that plane away the bone in thinner layers, with less chance of excess bone removal and membrane perforation.