Mechanical and fatigue resistance of restorations supported by welded-framework and realized using computer-aided designed prosthetic shells: In vitro pilot study.

Resin coating in implants rehabilitation cannot always be aesthetic, durable and comfortable for the patient mainly due to the limited dimensions of the final structure. Intraoral welding technique and computer-aided designed prosthetic shells may be a solution. This in vitro study evaluates the capacity of load and the weakest point of implant-supported provisional prosthesis using welded titanium framework. Twelve samples were produced to simulate an implant supported fixed prosthetic bridge. Two implants (Ankylos; Dentsply Sirona Implants; Germany) were inserted inside blocks of nanoceramic material produced with a stereolithographic 3D printer. A polymethylmethacrylate (PMMA) resin shell was performed with CAD/CAM and relined on welded framework. Six samples were produced with the same procedure reducing resin thickness. The samples were subjected to fatigue test (6,500,000 cycles) using ElectroForce 3310 fatigue machine (t1); subsequently a mechanical compression test using a universal Shimadzu AGS-X 10 machine (t2). The samples were analyzed with a photographic and radiographic documentation at t0, t1 and t2. The samples survived mechanical fatigue test without evidence of failure. The radiographic and photographic evaluation revealed the fracture of resin coating after the mechanical compression test. The samples with minimal resin thickness fractured first. Adequate assessment of the resin thickness is mandatory to improve the longevity of these rehabilitations. CAD-CAM digital prosthetic design allows us to optimize the thicknesses and the prosthetic shapes, allowing us to obtain good degrees of resistance even in the presence of reduced prosthetic spaces.

Computer-Aided Crown Design Using Digital Scanning Technology for Immediate Postextraction Single-Implant Restorations Supported by Conical Indexed Abutments.

Conical retention with antirotational features (Acuris abutment) has been recently proposed for restorations of healed single implants. The conometric abutments use the retentive force of the coping-abutment system to retain the prosthetic crown without the use of cement or screws. This retentive force must be overcome to obtain detachment of the relined provisional crown in immediate restorations. The present article describes the use of digital scanning technology to virtually plan computer-guided implant placement and restoration with conical indexed abutments in postextraction sites. Importing the scan data of both matrix and patrix abutments that are seated on the definitive cast into the computer-aided design software provides a workflow to preoperatively mill a crown that perfectly fits the abutment into the postextraction site. This technique simplifies the provisional crown relining onto the conometric indexed abutment and reduces the intraoperative time.

Guided-welded approach planning using digital scanning technology for combined screw- and conometric-retained implant-supported maxillary prosthesis.

AIM: The goal of this case series was to evaluate the clinical outcome at the 2-year follow-up of immediately loaded combined screw- and conometric-retained implant-supported full-arch restorations virtually planned using digital scanning technology. MATERIALS AND METHODS: This series included 12 patients presenting hopeless teeth in the maxilla treated with computer-guided flapless implant placement. A total of 72 implants were inserted. All implants were immediately loaded with a complete-arch restoration supported by an intraorally welded framework. Digital scanning technology was used to virtually plan a combined screw and conometric retention of the frameworks. Clinical parameters were assessed at 1 week and at 1, 3, 6, 12, and 24 months follow-up. RESULTS: The survival rate after 2 years was 98.6%, as one implant failed during the osseointegration period. No major prosthetic complications were observed such as issues with mobility, unscrewed abutments, disconnected conometric copings, and prosthetic fracture. Only one patient registered the chipping of a prosthesis. CONCLUSION: Based on the results of the present study, the use of combined screw and conometric retention for fixed immediate restorations properly planned using digital scanning technology seems to be a viable treatment alternative to screw or conometric retention alone for immediately loaded rehabilitations.

Guided-welded approach planning using a computer-aided designed prosthetic shell for immediately loaded complete-arch rehabilitations supported by conometric abutments.

In guided surgery, implants can be planned from radiographic guide information according to a restoratively driven treatment plan. Unfortunately, the palatal or lingual surface of teeth cannot be easily identified. The present article describes the use of a digitally designed prosthetic shell to improve the accuracy of guided-welded approach planning for immediate restorations supported by conometric abutments. Importing the virtual shell into the planning software provides an effective protocol for using the definitive prosthetic space information to plan the framework shape and position predictably. This method increases the accuracy of virtual planning and reduces the time needed to reline the prosthetic shell.

Implementation of computer-guided implant planning using digital scanning technology for restorations supported by conical abutments: A dental technique.

Conometric retention has recently been proposed as an alternative to cement- or screw-retention for fixed restorations. Conometric copings can only compensate for slightly nonparallel placement without interfering with retention. This article describes a method of using digital scanning technology to facilitate computer-guided implant planning when an immediate restoration supported by conical abutments is planned with a guided-welded approach. The procedure involves importing the scan data of the conometric coping and of the definitive cast obtained from the surgical template into the implant planning software. This approach increases the accuracy of computer-guided implant planning and reduces the time needed for the surgery.

Use of Intraoral Welding to Increase the Predictability of Immediately Loaded Computer-Guided Implants.

Inaccuracy of computer-guided implant placement may lead to complications when combined with an immediately loaded prefabricated prosthesis. The aim of this case series was to describe the use of an intraoral welding technique to increase the predictability of immediately loaded implants supporting a fixed full-arch prosthesis after computer-guided flapless implant placement. A total of 60 Ankylos plus implants (Dentsply) with a width of 3.5 mm and a length of 8 to 14 mm were placed consecutively in 10 patients. The implants were functionally loaded using the intraoral welding technique on the day of surgery. The accuracy of guided implant placement was assessed by matching the planning cone beam computed tomography (CBCT) scans with postoperative CBCT scans. No mechanical or biologic complications were registered at the 1-year follow-up. The global coronal deviation of implant placement from the guide plan ranged from 0.25 to 2.84 mm (SD: 0.6 mm), with a mean of 1.28 mm. Average angle deviation was 3.42 degrees (range 0.38-7.82 degrees; SD: 1.52 degrees). The global apical deviation ranged between 0.36 and 3.85 mm (SD: 0.71 mm), with a mean of 1.65 mm. Despite the inaccuracy registered, this guided-welded approach allowed successful achievement of a passive fit of the full-arch prosthesis on the inserted implants the same day of the surgery and provided a high implant and prosthetic survival rate at the 1-year follow-up.

Computer-assisted surgery and intraoral welding technique for immediate implant-supported rehabilitation of the edentulous maxilla: case report and technical description.

BACKGROUND: Complications are frequently reported when combining computer assisted flapless surgery with an immediate loaded prefabricated prosthesis. The authors have combined computer-assisted surgery with the intraoral welding technique to obtain a precise passive fit of the immediate loading prosthesis. METHODS: An edentulous maxilla was rehabilitated with four computer assisted implants welded together intraorally and immediately loaded with a provisional restoration. RESULTS: A perfect passive fit of the metal framework was obtained that enabled proper osseointegration of implants. Computer assisted preoperative planning has been shown to be effective in reducing the intraoperative time of the intraoral welding technique. No complications were observed at 1 year follow-up. CONCLUSIONS: This guided-welded approach is useful to achieve a passive fit of the provisional prosthesis on the inserted implants the same day as the surgery, reducing intraoperative time with respect to the traditional intraoral welding technique. Copyright © 2015 John Wiley & Sons, Ltd.

A computer-guided bone block harvesting procedure: a proof-of-principle case report and technical notes.

During autogenous mandibular bone harvesting, there is a risk of damage to anatomical structures, as the surgeon has no three-dimensional control of the osteotomy planes. The aim of this proof-of-principle case report is to describe a procedure for harvesting a mandibular bone block that applies a computer-guided surgery concept. A partially dentate patient who presented with two vertical defects (one in the maxilla and one in the mandible) was selected for an autogenous mandibular bone block graft. The bone block was planned using a computer-aided design process, with ideal bone osteotomy planes defined beforehand to prevent damage to anatomical structures (nerves, dental roots, etc) and to generate a surgical guide, which defined the working directions in three dimensions for the bone-cutting instrument. Bone block dimensions were planned so that both defects could be repaired. The projected bone block was 37.5 mm in length, 10 mm in height, and 5.7 mm in thickness, and it was grafted in two vertical bone augmentations: an 8 × 21-mm mandibular defect and a 6.5 × 18-mm defect in the maxilla. Supraimposition of the preoperative and postoperative computed tomographic images revealed a procedure accuracy of 0.25 mm. This computer-guided bone harvesting technique enables clinicians to obtain sufficient autogenous bone to manage multiple defects safely.

Immediately Loaded Intraorally Welded Complete-Arch Maxillary Provisional Prosthesis.

Guided implant surgery is not completely accurate when using computer-designed stereolithographic surgical guides. Complications are frequently reported when combining computer-guided flapless surgery with an immediately loaded prefabricated prosthesis. Achieving passive fit of a prefabricated prosthesis on the inserted implants the same day of the surgery can be difficult. The aim of this report is to show a new treatment approach to immediately loaded implants inserted with computer-guided surgery using an intraoral welded full-arch provisional prosthesis.

Buccal plate regeneration with immediate postextraction implant placement and restoration: case reports.

The loss of the buccal alveolar plate following tooth extraction in the maxillary anterior region is an especially challenging condition for the clinician. Immediate implant placement with a flapless approach has been suggested in order to reduce postextraction bone loss. In the presence of a significant vertical gap in the buccal plate after tooth extraction, most authors still recommend a bone augmentation procedure before implant placement. In these reports, buccal bone plate regeneration was obtained through a flapless approach and immediate postextraction implant placement with a cancellous bone and collagen graft in the buccal gap.

Endoscopically assisted enucleation and curettage of large mandibular odontogenic keratocyst.

This article reports a case of a mandibular multilocular keratocyst treated with endoscopically assisted enucleation and curettage. An ectopic third molar displaced in the coronoid process area was also removed.Odontogenic keratocysts (OKCs) are known for their propensity to recur. The incomplete removal of the cyst is one of the mechanisms for which it is thought that the keratocyst recurs. The endoscopic assistance allowed us to explore accurately the operative field and the areas of difficult access, improving the complete removal of the cystic lesion. Moreover, it allowed us to monitor closely the separation of the cyst lining from the inferior alveolar nerve and limit the extension of the surgical approach. At 3-year follow-up no evidence of recurrence was evidenced by radiological and clinical controls.

Arthroscopy with open surgery for treatment of synovial chondromatosis of the temporomandibular joint.

We report a case of synovial chondromatosis of the temporomandibular joint in which both joint compartments were affected. Because of the important involvement of the medial aspect of the joint, arthrotomy was done with arthroscopic assistance.

Is there a role for arthrocentesis in recapturing the displaced disc in patients with closed lock of the temporomandibular joint?

OBJECTIVE: The aim of this study was to evaluate the effectiveness of arthrocentesis in releasing acute and chronic closed lock of the temporomandibular joint, improving function, reducing pain and recapturing the displaced disc. STUDY DESIGN: We performed arthrocentesis and mandibular manipulation (MM) as an initial treatment in 33 patients (unilateral involvement) with a variable duration of closed lock and magnetic resonance imaging (MRI) evidence of anterior disc displacement without reduction (ADDWR). Duration of locking ranged from 1 week to 2 years. After the procedure, soft diet, physiotherapy, and an interocclusal appliance (IA) were prescribed. Postoperative MRI images were obtained at 1 month. A clinical examination with analysis of maximal mouth opening (MMO), a visual analog scale (VAS), and a self-administered questionnaire were used for evaluation of pain, jaw dysfunction, and activities of daily living (ADL). The follow-up period was 1 year. RESULTS: At 1-year follow-up, MMO had increased significantly from a mean of 24.7 +/- 5.9 mm to 39.6 +/- 6.2 mm (P < .05). Functional improvement was associated with a significant reduction in VAS (from 6.2 +/- 2.3 to 2.8 +/- 3.4), pain (from 11.7 +/- 7.1 to 4 +/- 3.8), dysfunction (from 8.6 +/- 4.9 to 3.2 +/- 2.8), and ADL scores (from 13.9 +/- 12 to 4.4 +/- 5), with P < .05. The overall success rate was 72.7%; it was higher in acute patients (87.5%) than in chronic patients (68.0%). The disc was recaptured (the disc was interposed between the condyle and the eminence on closed and open MRI images) in 3 cases in which the duration of locking was less than 1 month (acute patients). CONCLUSIONS: The results indicate that arthrocentesis, in association with MM and IA, could be effective in improving function and reducing pain in patients with closed lock. Better results were obtained in terms of MMO, VAS, and questionnaire scores in acute closed lock cases than in chronic ones. Recapturing the anteriorly displaced disc is possible only in patients with acute closed lock.

Intraoral endoscopically assisted treatment of temporomandibular joint ankylosis: preliminary report.

Temporomandibular joint (TMJ) ankylosis is characterized by the formation of a bony or fibrous mass that replaces the normal articulation. To avoid a possible re-ankylosis it is mandatory to perform a radical, complete resection of the bony/fibrous mass. We treated a patient affected by right temporomandibular joint ankylosis performing the osteotomy of the ankylotic mass through a preauricular and intraoral approach under endoscopic control. Then a temporalis muscle and fascia flap were used as the interpositional material. Through the endoscope it was easy to check the medial aspect of the resection and suture the flap. At 1-year follow-up the patient had significantly increased maximal mouth opening. No evidence of relapse of the joint ankylosis was shown by radiological studies. Intraoral endoscopic assistance may be useful to make the removal of the ankylotic mass safer, and the anchorage of the temporalis muscle and fascia flap more accurate, reducing the risk of re-ankylosis.

Septic arthritis of the temporomandibular joint successfully treated with arthroscopic lysis and lavage: case report and review of the literature.

Septic arthritis of the temporomandibular joint (TMJ) is infrequently reported. We present a case of septic arthritis of the TMJ following the extraction of the left upper second molar that occurred 1 week before beginning of symptoms. No evident predisposing factors were detected. Arthroscopic diagnosis of septic arthritis, lysis and lavage, and capsular stretch were performed. Cultures taken from the TMJ space grew Streptococcus sp. After 1 month of antimicrobial therapy the patient was asymptomatic and mandibular function was normal. Literature related to septic arthritis of TMJ and its treatment was reviewed. Different surgical procedures are available to treat this condition. Arthroscopy should be preferred as initial treatment on account of the possibility of drainage and accurate lavage under direct visualization of joint space, at the same time allowing confirmation of diagnostic hypotheses. Improving joint mobility with lysis of adhesions and capsular stretch in an early stage of disease may be helpful in stopping the fibrosis process.