Implant site preparation with piezoelectric technique versus drill technique: a clinical pilot study

La chirurgia piezoelettrica è una tecnica che permette il taglio selettivo dei soli tessuti duri diminuendo in maniera significativa il rischio di danno iatrogeno a strutture vascolo nervose. Studi recenti su animali sembrano ipotizzare inoltre la capacità della piezochirugia di migliorare e anticipare le fasi iniziali del processo di guarigione ossea e di osteintegrazione. Da qui l’obiettivo dello studio che è stato la valutazione quantitativa e qualitativa della rigenerazione ossea ottenuta in seguito a preparazione del sito implantare tramite tecnica piezoelettrica e tecnica convenzionale. Lo studio ha compreso il trattamento di 12 siti edentuli adatti ad essere riabilitati con terapia implantare. Durante le normali procedure di chirurgia implantare tali siti ricevevano anche l’inserimento di una fixture implantare aggiuntiva di dimensioni ridotte: nel Gruppo Test l’inserimento ti tale fixture è avvenuto con preparazione del sito implantare con tecnica piezoelettrica; nel gruppo controllo con tecnica a fresa convenzionale. Dopo 28 giorni (T1) le fixture aggiuntive sono state espiantate e per ogni gruppo è stata valutata la rigenerazione ossea ottenuta con analisi istologica e immunoistochimica con marcatori SATB2 e CD31. Tutti i campioni sia del gruppo test che del gruppo controllo mostrano un quadro istologico sovrapponibile. In ogni campione di ciascun gruppo si osserva la presenza di osso trabecolare residuo in vari stadi di necrobiosi associato ad aspetti di osteo-rigenerazione in diversi fasi che portano alla formazione di osso trabecolare. La valutazione dei marcatori SATB2 e CD31 Non ha mostrato differenze significative tra i due gruppi (P>0.05). I risultati preliminari di questo studio sembrano mostrare che l’osteo-rigenerazione che si verifica in seguito a preparazione del sito implantare con tecnica piezoelettrica o tecnica convenzionale risulti similare facendo ipotizzare quindi che la rigenerazione ossea di entrambe le tecniche segua le medesime fasi e tempistiche biologiche.Piezoelectric surgery is a promising technique for the selective cut of the hard tissues that significantly decrease the risk of iatrogenic damage to nerve vessel structures during oral and implant surgery. In addition some recent studies suggested that ultrasonic implant site preparation seems to have the potential to modify biologic events during the osseointegration initial phases. Hence the objective of the study that was the histological quantitative and qualitative evaluation of bone regeneration obtained following the preparation of the implant site using piezoelectric technique or drill technique. The study included 12 edentulous sites suitable for rehabilitation with implant therapy. During the normal implant surgery procedures, these sites also received the insertion of a small additional implant fixture: in the Test Group, the additional fixture was inserted with piezoelectric implant site preparation, otherwise in the control group with drill preparation. After 28 days (T1) the additional fixtures were trephined and histologic and immunohistochemical analysis with SATB2 and CD31 markers were performed to detect any differences between the two study group (P>0.05). All samples of both test group and control group showed similar histologic features. In each sample of both groups there were the presence of residual trabecular bone in different stages of necrobiosis associated with osteo-regeneration aspects. Evaluation of the SATB2 and CD31 markers did not show significant differences between the two groups. Preliminary results of this study seem to show that osteo-regeneration occurring following implant site preparation with piezoelectric or conventional technique is similar, suggesting that bone regeneration of both techniques follows the same biological phases and times

Minimally Invasive Approach Based on Pterygoid and Short Implants for Rehabilitation of an Extremely Atrophic Maxilla: Case Report

Introduction: Extremely atrophic maxillae can be considered the most important indication for three-dimensional maxillary reconstruction. Different bone-augmentation techniques have been suggested to accomplish this. This article illustrates a minimally invasive approach to rehabilitation of the extremely atrophic maxilla. Material and Methods: A 63-year-old male patient was referred for restoration of his totally edentulous maxilla with a fixed full-arch implant-prosthetic rehabilitation. Four short implants in the premaxillary region and 2 longer implants in the pterygomaxillary regions were inserted with piezoelectric implant site preparation. Discussion: At the 1-year follow-up appointment, no clinical or radiographic changes in the soft-tissue contours or crestal bone levels were observed. Conclusion: This surgical approach, based on the combination of short implants in the premaxillary regions and pterygoid implants in the pterygomaxillary regions, represents a way to shorten treatment timing, minimize the risk of surgical complications, and reduce patient discomfort and costs

INFLUENCE OF SECONDARY WOUND HEALING AFTER MANDIBULAR THIRD MOLAR CORONECTOMY

Our aim was to describe the postoperative morbidity related to secondary wound healing after coronectomy. Ten of 116 patients treated by coronectomy healed by second intention as a result of failed sutures. We made a retrospective analysis after two years to evaluate the postoperative morbidity related to secondary wound healing. The complete closure of the alveolus of the 10 surgical sites was recorded three months after coronectomy. No patients had postoperative infections, dry socket, or pulpitis. All patients were free of symptoms, the retained roots were completely included, and were not detectable with a periodontal probe. The importance of primary wound closure after coronectomy has been stressed as a critical point to avoid postoperative infection of the root. We found that secondary wound healing after coronectomy was not associated with a high postoperative infection rate, but further randomised clinical studies are necessary to confirm the need for primary closure and its relations to the long-term success of the coronectom

Coronectomy of mandibular third molars: A clinical protocol to avoid inferior alveolar nerve injury

Coronectomy is a surgical procedure for the treatment of mandibular third molars in close proximity to the mandibular canal. Unfortunately, often the surgical protocol is not described step by step and it is difficult for the clinician to assess the key factors that are important for the success of this procedure. The aim of this paper is to propose and describe a standardized surgical protocol to improve the success of the technique. The treatment approach, for the most common types of third molars impaction is analysed. Each step of the surgical procedure is described in details and a new type of crown section is proposed. The presented protocol is proposed in order to define a clinical practitioner's guide that could help the surgeon who approaches coronectomy for the first times

GOOD NEUROLOGICAL RESULTS WITH CORONECTOMY IN THE THIRD MANDIBULAR MOLAR SURGERY: CASE SERIES STUDY

Inferior alveolar nerve (IAN) injury (IANI) is a possible postoperative complication occurring after mandibular third molar surgery (1). According to the literature the percentage of temporary injury to the alveolar nerve goes from 0.4% to the 8.4% (2), whereas permanent injury occurs in up to 3% of cases (3,4) Even thought rare, the consequences of this kind of complications should not be underestimated. Injuries to the alveolar inferior nerve cause a considerable discomfort in patients (1) and often result in lawsuits against the surgeon. In order to avoid this kind of complication, clinicians studied surgical alternative options for the treatment of impacted third molars in close proximity to the inferior alveolar nerve. Coronectomy is today one of these alternative (6-8). This surgical technique was first proposed by Ecuyer and Debien in 1984 and consists in the removal of the crown, deliberately leaving in situ the part of the tooth that has a relationship with the IAN: the roots (9). The aims of this study are to describe, after three years of coronectomies, a surgical protocol to improve the clinical success of coronectomy, and evaluate the postoperative complications of 93 coronectomies of the lower third molars

A Proposal of Pseudo-periosteum Classification After GBR by Means of Titanium-Reinforced d-PTFE Membranes or Titanium Meshes Plus Cross-Linked Collagen Membranes

After (GBR) with different devices, a layer of connective tissue calledcan be observed above the newly formed bone. The aim of this study is to evaluate the clinical and histologic features and to suggest a classification of this connective tissue after GBR with nonresorbable membranes or titanium (Ti)-mesh plus resorbable membranes. Forty patients with partial edentulism in the posterior mandible were randomized into two groups: 20 patients were treated by means of Ti-reinforced dense polytetrafluoroethylene (d-PTFE) membrane (group A), while the other 20 patients were treated with Ti-mesh and a cross-linked collagen membrane (group B). After 9 months and during re-opening surgery, bone density and pseudo-periosteum type were recorded. Pseudo-periosteum was classified into Type 1 (no tissue or tissue < 1 mm); Type 2 (regular tissue between 1 and 2 mm); and Type 3 (irregular tissue or tissue > 2 mm). Histologic analyses were performed to identify the features of pseudo-periosteum. Out of 40 patients, 36 (n = 19 in Group A; n = 17 in Group B) with 99 implants were analyzed after GBR and according to the study protocol. The vertical bone gain was 4.2 \ub1 1.0 mm in Group A and 4.1 \ub1 1.0 mm in Group B. Group A had a higher bone density and greater amounts of type 1 periosteum than Group B (P = .01 for both). The preliminary results of this study show that both d-PTFE membranes and Ti-mesh plus collagen membranes are two valid options for bone augmentation in the mandible. However, nonresorbable membranes achieve higher bone density and a thinner pseudo-periosteum layer above the newly formed bone

Evaluation of Crestal Bone Loss Around Straight and Tilted Implants in Patients Rehabilitated by Immediate-Loaded Full-Arch All-on-4 or All-on-6: A Prospective Study

The aim of this prospective study was to compare implant success rate and crestal bone loss around tilted and straight implants supporting immediate-loading full-arch rehabilitations. Twenty consecutive patients with edentulous jaws treated between June 2013 and July 2015 who satisfied all inclusion and exclusion criteria were included in the study. All patients were rehabilitated through a full-arch restoration supported by 4 or 6 immediately loaded implants. Clinical and radiographic examinations were scheduled every 12 months to evaluate implant success rates and crestal bone levels. Significant differences in crestal bone levels and success rates between straight and tilted implants were investigated by means of independent statistical analysis; differences were regarded as significant if P < .05. Seventy straight and 50 tilted implants were placed to rehabilitate 14 mandibles and 12 maxillae in 20 patients. After a follow-up of 12 to 36 months, survival rate was 97.1% for straight implants and 96.0% for tilted implants; while success rates were 94.3% and 94.0%, respectively. Success and survival rates were not significantly different (P > .05). Change in crestal bone level was 0.5 +/- 0.4 mm for straight implants and 0.6 +/- 0.4 mm for tilted implants (P > .05). Straight and tilted implants seemed to have similar behavior after immediate loading rehabilitations. After functional loading, straight and tilted implants did not differ significantly in clinical outcome

Periodontal Healing Distally to Second Mandibular Molar After Third Molar Coronectomy

Purpose Coronectomy of mandibular third molars is a procedure that still raises a number of questions. The aim of the present study was to answer one unsolved question: the periodontal healing distal to the mandibular second\ua0molar after third molar coronectomy. Materials and Methods A prospective cohort study was performed of 30 patients treated at the Unit of Oral and Maxillofacial Surgery of the Department of Biomedical and Neuromotor Science of the University of Bologna. The predictor variables were the probing pocket depth (PPD), the distance between the marginal crest (MC) and the bottom of the osseous defect (BOD), and the distance between the cementum enamel junction (CEJ) and the BOD. These clinical indexes were recorded on 3 points of the distal surface of second\ua0molar: the distobuccal (DB), distomedial (DM), and distolingual (DL) sites. The other variables evaluated included root migration and postoperative complications. The Wilcoxon test for paired data and Kendall's tau-b correlation coefficient was used to evaluate all variables. The significance level was set at P\ua0= .05. Results The cohort was composed of 30 patients with 34 high-risk mandibular third molars (9 men and 21 women), with a mean age of 28 \ub1 7\ua0years. At 9\ua0months, a statistically significant reduction in the PPD of 2 \ub1 3, 1 \ub1 2, and 2 \ub1 2\ua0mm and a statistically significant reduction in the MC-BOD distance of 4 \ub1 4, 4 \ub1 4, and 4 \ub1 5\ua0mm for the DB, DM, and DL sites, respectively, was observed (P\ua0= .001). Also, the intraoperative CEJ-BOD distance showed a statistically significant reduction for the DB, DM, and DL sites. Conclusions After coronectomy, restoration of a clinical healthy periodontium distal to the second\ua0molar was observed. However, further studies are necessary to confirm these preliminary clinical results and to compare periodontal healing between coronectomy and complete extraction

Clinical and volumetric outcomes after vertical ridge augmentation using computer-aided-design/computer-aided manufacturing (CAD/CAM) customized titanium meshes: a pilot study

Background: One of the most recent innovations in bone augmentation surgery is represented by computer- aided-design/computer-aided-manufacturing (CAD/CAM) customized titanium meshes, which can be used to restore vertical bone defects before implant-prosthetic rehabilitations. The aim of this study was to evaluate the effectiveness/reliability of this technique in a consecutive series of cases. Methods: Ten patients in need of bone augmentation before implant therapy were treated using CAD/CAM customized titanium meshes. A digital workflow was adopted to design virtual meshes on 3D bone models. Then, Direct Metal Laser Sintering (DMLS) technology was used to produce the titanium meshes, and vertical ridge augmentation was performed according to an established surgical protocol. Surgical complications, healing complications, vertical bone gain (VBG), planned bone volume (PBV), lacking bone volume (LBV), regenerated bone volume (RBV), average regeneration rate (RR) and implant success rate were evaluated. Results: All augmented sites were successfully restored with definitive implant-supported fixed partial dentures. Measurements showed an average VBG of 4.5 \ub1 1.8 mm at surgical re-entry. Surgical and healing complications 3 occurred in 30% and 10% of cases, respectively. Mean values of PBV, LBV, and RBV were 984, 92, and 892 mm , respectively. The average RR achieved was 89%. All 26 implants were successfully in function after 1 year of follow- up. Conclusions: The results of this study suggest that the bone augmentation by means of DMLS custom-made titanium meshes can be considered a reliable and effective technique in restoring vertical bone defects