Successful Management of Peri-Implantitis around Short and Ultrashort Single-Crown Implants: A Case Series with a 3-Year Follow-Up.

INTRODUCTION AND AIM: In case of peri-implantitis, resective surgery is contraindicated for short and ultrashort implants, limiting the treatment options to regenerative surgery or to implant removal. This retrospective case series presents the clinical and radiographic outcomes of a surgical regenerative procedure to treat peri-implantitis around short and ultrashort implants. MATERIALS AND METHODS: The study is a retrospective evaluation of patients suffering from peri-implantitis and those who underwent access flap surgery, concomitant chemical and mechanical decontamination of implant surface, and bone grafting using a self-hardening mixture of bone substitutes and biphasic calcium sulfate. No membranes were applied to cover the grafting material, and primary tension-free closure was achieved. The retrospective protocol was reviewed and approved by the Ethics Committee for Clinical Sperimentation (CESC) of Verona and Rovigo, Italy (based in the University of Verona) (Prog. 1863CESC. Date of approval: 2018-07-04). RESULTS: 15 patients (17 implants) have been diagnosed with peri-implantitis after a mean follow-up of 24 months after loading. Implant length was between 5 and 8 mm. 8 patients (10 implants) had a history of periodontitis. At baseline, the mean PD (probing pocket dept) at the deepest site was 8.12 mm, with an average mBI (modified bleeding index) of 2.35 and a mean BD (bone defect depth) of 3.04 mm. At the 3-year follow-up, the CSR was 100%, the mean mBI was 0.88 (average reduction: -1.47), the mean PD was 3.35 mm (mean PD reduction: 4.77 mm), and the mean bone defect was reduced by 1.74 mm, with a mean bone fill of 55%. CONCLUSIONS: The results of the present case series suggest that if accurate surface decontamination is achieved, high survival rate and good clinical and radiographic results can be obtained after 3 years. However, only the histological examination could confirm the growth of new bone in direct contact with the implant surface or if the grafted material only fills the space left by the peri-implant defect.

Aesthetic Surgical Approach for Bone Dehiscence Treatment by Means of Single Implant and Interdental Tissue Regeneration: A Case Report with Five Years of Follow-Up.

The replacement of single anterior teeth by means of endosseous implants implies the achievement of success in restoring both aesthetic and function. However, the presence of wide endoperiodontal lesions can lead to horizontal hard and soft tissues defects after tooth extraction, making it impossible to correctly place an implant in the compromised alveolar socket. Vertical augmentation procedures have been proposed to solve these clinical situations, but the amount of new regenerated bone is still not predictable. Furthermore, bone augmentation can be complicated by the presence of adjacent teeth, especially if they bring with them periodontal defects. Therefore, it is used to restore periodontal health of adjacent teeth before making any augmentation procedures and to wait a certain healing period before placing an implant in vertically augmented sites, otherwise risking to obtain a nonsatisfactory aesthetic result. All of these procedures, however, lead to an expansion of treatment time which should affect patient compliance. For this reason, this case report suggests a surgical technique to perform vertical bone augmentation at a single gap left by a central upper incisor while placing an implant and simultaneously to regenerate the periodontal attachment of an adjacent lateral incisor, without compromising the aesthetic result.

The Immediate Aesthetic and Functional Restoration of Maxillary Incisors Compromised by Periodontitis Using Short Implants with Single Crown Restorations: A Minimally Invasive Approach and Five-Year Follow-Up.

The functional and aesthetic restoration of teeth compromised due to aggressive periodontitis presents numerous challenges for the clinician. Horizontal bone loss and soft tissue destruction resulting from periodontitis can impede implant placement and the regeneration of an aesthetically pleasing gingival smile line, often requiring bone augmentation and mucogingival surgery, respectively. Conservative approaches to the treatment of aggressive periodontitis (i.e., treatments that use minimally invasive tools and techniques) have been purported to yield positive outcomes. Here, we report on the treatment and five-year follow-up of patient suffering from aggressive periodontitis using a minimally invasive surgical technique and implant system. By using the methods described herein, we were able to achieve the immediate aesthetic and functional restoration of the maxillary incisors in a case that would otherwise require bone augmentation and extensive mucogingival surgery. This technique represents a conservative and efficacious alternative to the aesthetic and functional replacement of teeth compromised due to aggressive periodontitis.

Decontamination using a desiccant with air powder abrasion followed by biphasic calcium sulfate grafting: a new treatment for peri-implantitis.

Peri-implantitis is characterized by inflammation and crestal bone loss in the tissues surrounding implants. Contamination by deleterious bacteria in the peri-implant microenvironment is believed to be a major factor in the etiology of peri-implantitis. Prior to any therapeutic regenerative treatment, adequate decontamination of the peri-implant microenvironment must occur. Herein we present a novel approach to the treatment of peri-implantitis that incorporates the use of a topical desiccant (HYBENX), along with air powder abrasives as a means of decontamination, followed by the application of biphasic calcium sulfate combined with inorganic bovine bone material to augment the intrabony defect. We highlight the case of a 62-year-old man presenting peri-implantitis at two neighboring implants in positions 12 and 13, who underwent access flap surgery, followed by our procedure. After an uneventful 2-year healing period, both implants showed an absence of bleeding on probing, near complete regeneration of the missing bone, probing pocket depth reduction, and clinical attachment gain. While we observed a slight mucosal recession, there was no reduction in keratinized tissue. Based on the results described within, we conclude that the use of HYBENX and air powder abrasives, followed by bone defect grafting, represents a viable option in the treatment of peri-implantitis.

Regulation of Axolotl (Ambystoma mexicanum) Limb Blastema Cell Proliferation by Nerves and BMP2 in Organotypic Slice Culture.

We have modified and optimized the technique of organotypic slice culture in order to study the mechanisms regulating growth and pattern formation in regenerating axolotl limb blastemas. Blastema cells maintain many of the behaviors that are characteristic of blastemas in vivo when cultured as slices in vitro, including rates of proliferation that are comparable to what has been reported in vivo. Because the blastema slices can be cultured in basal medium without fetal bovine serum, it was possible to test the response of blastema cells to signaling molecules present in serum, as well as those produced by nerves. We also were able to investigate the response of blastema cells to experimentally regulated changes in BMP signaling. Blastema cells responded to all of these signals by increasing the rate of proliferation and the level of expression of the blastema marker gene, Prrx-1. The organotypic slice culture model provides the opportunity to identify and characterize the spatial and temporal co-regulation of pathways in order to induce and enhance a regenerative response.

Characterization of in vitro transcriptional responses of dorsal root ganglia cultured in the presence and absence of blastema cells from regenerating salamander limbs.

During salamander limb regeneration, nerves provide signals that induce the formation of a mass of proliferative cells called the blastema. To better understand these signals, we developed a blastema-dorsal root ganglia (DRG) co-culture model system to test the hypothesis that nerves differentially express genes in response to cues provided by the blastema. DRG with proximal and distal nerve trunks were isolated from axolotls (Ambystoma mexicanum), cultured for five days, and subjected to microarray analysis. Relative to freshly isolated DRG, 1,541 Affymetrix probe sets were identified as differentially expressed and many of the predicted genes are known to function in injury and neurodevelopmental responses observed for mammalian DRG. We then cultured 5-day DRG explants for an additional five days with or without co-cultured blastema cells. On Day 10, we identified 27 genes whose expression in cultured DRG was significantly affected by the presence or absence of blastema cells. Overall, our study established a DRG-blastema in vitro culture system and identified candidate genes for future investigations of axon regrowth, nerve-blastema signaling, and neural regulation of limb regeneration.

Position-specific induction of ectopic limbs in non-regenerating blastemas on axolotl forelimbs.

Ectopic retinoic acid (RA) has been hypothesized to reprogram the positional identity of cells in developing and regenerating limbs to a single positional value corresponding to the posterior-ventral-proximal (PVPr) position on the limb. We tested this hypothesis by using RA to reprogram the information of blastema cells that were induced to form at different positions around the limb circumference. We observed that RA treatment of blastemas in anterior and dorsal locations, but not posterior and ventral locations, resulted in the induction of complete ectopic limbs. These position-specific differences in limb induction are probably due to differences in the positional disparity between the RA-reprogrammed blastema cells and the cells at the periphery of the wound. These observations are consistent with the hypothesis that RA treatment reprograms the information in blastema cells to the PVPr position on the limb, since anterior and dorsal positions have the largest disparity and posterior and ventral have the smallest disparity from the PVPr identity.