Digital planning for two-implant-supported overdenture and bone reduction guide using cone-beam computed tomography: Simple features for predictable outcomes

The two-implant-supported mandibular overdenture is considered a reliable treatment option to restore masticatory function. Digital planning has been shown to improve the precision and accuracy of the surgical procedure. The outcomes are indeed pertinent to the ideal three-dimentional positioning of the implant placement. Recently, the uses of cone-beam computed tomography (CBCT) and intraoral scan have improved greatly the workflow of digital planning; however, the sophisticated technology caused confusion among clinicians. The purpose of this case series was to exhibit the efficacy of a bone-supported guide in applying simultaneous implant placement and bone reduction, solely based on CBCT data. The bone reduction can therefore be determined accordingly, by adding windows to the guide, allowing the clinician to decide the amount of bone reduction as well as the location for implant placement. This novel surgical guide would not only fit properly on the bone but also provide the benefits of less-invasive surgery and the opportunity to place implants parallel. The  digital workflow described not only simplifies the fabrication process but also yields predictable surgical outcomes.

Digital Workflow in Implant Treatment Planning For Terminal Dentition Patients

Treatment planning for the transition of patients from terminal dentition to full-arch implant rehabilitation poses challenges. Such challenges pertain to achieving the new orientation of the occlusal and esthetic plane as well as the change of vertical dimension of occlusion (VDO), while the fixed provisionalization using a digital workflow, still tends to be considered complex and hard to perform. This article illustrates step-by-step the utilization of a digital workflow protocol in the treatment planning for rehabilitation of terminal dentition patients, simplifying the smile design and ensuring that fixed provisionalization serves both the functional and esthetic requirements. This protocol includes facially-driven, three-dimensional (3D) digital smile design and chairside mock-up restoration workflows that enable prosthetically-driven assessment prior to implant treatment planning and 3D printing of surgical templates, which can predictably reduce chairside time and adjustments at the surgical and fixed provisionalization appointment. This article is protected by copyright. All rights reserved.

Sublingual emphysema following alveoloplasty: A case report

Various cases of introduction of air into soft tissues have been reported in the dental literature. Here, we report a rare case of localized sublingual emphysema after alveoloplasty. There was no facial involvement. The patient responded to treatment and recovered uneventfully.

Clinical and Histological changes after ridge preservation with two xenografts: preliminary results from a multicentre randomized controlled clinical trial

OBJECTIVES

To evaluate and compare clinical and histological changes after ridge preservation procedures with those of spontaneous healing.

MATERIALS AND METHODS

Ninety patients were enrolled in the present randomized controlled clinical trial and underwent single-tooth extraction in the premolar/molar areas. Thirty sites were grafted with collagenated cortico-cancellous (coll), 30 sites with cortical (cort) porcine bone and 30 sites underwent natural healing. Primary (vertical and horizontal bone changes after 3 months) and secondary outcomes (histomorphometric after 3 months) were evaluated at implant placement.

RESULTS

The vertical bone changes at the grafted sockets were significantly (p < 0.0001) lower (0.30 mm for cort group and 0.57 mm for coll group) when compared to non-grafted sockets (2.10 mm for nat group). Moreover, the width reduction of the coll (0.93 mm) and cort (1.33 mm) groups was significantly lower (p < 0.0001) than the non-grafted group (3.60 mm). The analysis of subgroups attested that when premolar and molar sites were compared, the buccal bone loss appeared to be dependent both on tooth position and grafting material employed.

CONCLUSION

The ridge preservation procedures had significantly better outcomes when compared to natural healing. The biomaterials did not differ for maintenance of bone width; even though, the bone height seemed to be better preserved with the cortical porcine bone.

Bone Reduction to Facilitate Immediate Implant Placement and Loading Using CAD/CAM Surgical Guides for Patients With Terminal Dentition

The aim of this study is to present a method, using 3 computer-aided design/computer-aided manufacturing (CAD/CAM) surgical guides, to accurately obtain the desired bone reduction followed by immediate implant placements and loading for patients diagnosed with terminal dentition. Patients who had bone reduction, implants placed, and immediate loading using Anatomage Invivo 5 CAD/CAM surgical guides between the period 2013 and 2015 were evaluated retrospectively. Patients diagnosed with terminal dentition and treated using the "3-guide technique" were identified. Pre- and postsurgical images were superimposed to evaluate deviations of the bone reduction and deviations at the crest, apex, and angle of implants placed. Twenty-six implants placed in 5 patients were included in this study. The overall deviation means measured for bone reduction was 1.98 mm. The overall deviation means measured for implant placement at the crest, apex, and angle were 1.43 mm, 1.90 mm, and 4.14°, respectively. The CAD/CAM surgical guide fabrication is an emerging tool that may facilitate the surgical process and aid in safe and predictable execution of bone reduction and immediate implant placement. Using 3 CAD/CAM surgical guides, a method is presented to obtain the desired bone reduction followed by immediate implant placement and loading for patients diagnosed with terminal dentition. This method may improve guide stability for patients with terminal dentition undergoing complete implant-supported treatment by taking advantage of the teeth to be extracted.

Volumetric analysis of remodelling pattern after ridge preservation comparing use of two types of xenografts. A multicentre randomized clinical trial

OBJECTIVES

The aim of this randomized clinical trial was to analyse and compare the volumetric changes after ridge preservation procedures using two different biomaterials and to evaluate associations between outcome variables and pristine three-dimensional aspects of the ridges.

MATERIALS AND METHODS

Twenty-eight patients subjected to single-tooth alveolar ridge preservation were enrolled in the present multicentre, single-blind, prospective and randomized clinical trial. Fourteen sites were randomly allocated to each experimental group. The experimental sites were grafted with pre-hydrated collagenated cortico-cancellous porcine bone (coll group) or with a cortical porcine bone (cort group) and a collagen membrane; a secondary soft tissue healing was obtained for all experimental sites. Plaster casts were scanned (preoperative, at 1 and 3 months postoperative). Analysis of volumes and areas was performed, and all measured variables were statistically compared.

RESULTS

Intragroup analyses at 3 months revealed that when examining changes related to three-dimensional features of remodelling patterns (volume, surfaces, height and shape), the two biomaterials showed similar behaviours with a minor loss in volume and ridge surface. Intergroup analysis at 3-month survey revealed that volume resorption of the coll group (244 mm³ ) was significantly lower (P = 0.0140) than that of the cort group (349 mm³ ). The reduction for basal surface appeared significantly different between the two groups at 1-month survey only (P = 0.0137), while the final basal surface reduction was 4.9 and 12.2 mm² for coll and cort group, respectively. The superior surface reduction was 40.8 mm² for coll and 50.7 mm² for cort group, with no significant difference between the two groups.

CONCLUSION

At the 3rd month analysis, coll group showed a significantly lower reduction of ridge volume and a significantly smaller shrinkage of the basal area when compared to the cort group; moreover, the coll group experienced a smaller superior surface shrinkage when compared to the cort group, even though no significance was evaluated.

Pre-prosthetic surgery: Mandible

Pre-prosthetic surgery is that part of oral and maxillofacial surgery which restores oral function and facial form. This is concerned with surgical modification of the alveolar process and its surrounding structures to enable the fabrication of a well-fitting, comfortable, and esthetic dental prosthesis. The ultimate goal of pre-prosthetic surgery is to prepare a mouth to receive a dental prosthesis by redesigning and smoothening bony edges.