Innovative approach to computer-guided surgery and fixed provisionalization assisted by screw-retained transitional implants.

PURPOSE: The objectives of this case series are to describe a novel clinical approach to treat completely edentulous patients and determine its viability. Computer-guided implant planning was used to create a screw-retained surgical template (ST) supported by transitional implants and a fixed screw-retained provisional prosthesis supported by the transitional implants at the time of definitive implant placement. MATERIALS AND METHODS: Five patients with at least one edentulous arch were treated. After the diagnostic tooth setup was performed, a duplicate with radiopaque acrylic resin was fabricated to serve as a surgical template (ST) for the placement of screw-form transitional implants and a radiographic guide (RG). Four transitional implants were strategically placed through the guide where they would not interfere with the future definitive implants. The transitional implants were used to support the RG during computed tomographic scanning. Subsequently, the RG was converted into a second ST based on three-dimensional virtual planning. Eight implants were placed by the computer-guided system, and an immediate prefabricated fixed provisional was connected to the transitional implants. RESULTS: All the implants included in the study achieved primary stability and osseointegrated successfully. For 4 months, the transitional implants served successfully as abutments for the provisional prosthesis. CONCLUSION: This innovative clinical approach overcomes the limitations of a mucosa/bone-supported ST by offering fixed, reproducible support for the RG and ST by means of transitional implants. The delivery of a prefabricated screw-retained provisional on transitional implants allows for passive healing and minimum chairside adjustments.

A comparative study of the incidence of Schneiderian membrane perforations during maxillary sinus augmentation with a sonic oscillating handpiece versus a conventional turbine handpiece.

BACKGROUND: Sonic instruments may reduce perforation rates of the schneiderian membrane during lateral window sinus augmentation procedures. This study compares the incidence of membrane perforations using a sonic handpiece with an oscillating diamond insert versus a turbine handpiece with a conventional rotary diamond stone during lateral window sinus augmentation procedures. MATERIALS AND METHODS: A retrospective chart analysis identified all lateral window sinus augmentation procedures done during a defined period. Among these procedures, those performed with a sonic handpiece and an oscillating diamond insert (experimental) and those performed with a conventional turbine and rotary diamond stone (conventional) were selected for this study. Reported occurrences of sinus membrane perforations during preparation of the osteotomy and elevation of the sinus membrane, as well as postoperative complications, were recorded and compared between treatment groups. RESULTS: Ninety-three consecutive patients were identified for a total of 130 sinus augmentation procedures (51 conventional, 79 experimental). Schneiderian membrane perforations were noted during preparation of the lateral window osteotomy in 27.5% of the sinuses in the conventional group and 12.7% of sinuses in the experimental group. During membrane elevation, perforations were noted in 43.1% of the sinuses in the conventional group and 25.3% of sinuses in the experimental group. Both differences in perforation rates were statistically significant (p < .05). There was no statistically significant difference in postoperative complications. CONCLUSIONS: In this study, the use of a sonic instrument to prepare the lateral window osteotomy during sinus elevation procedures resulted in a reduced perforation rate of the Schneiderian membrane compared with the conventional turbine instrument.

Peri-implant soft tissue and marginal bone adaptation on implant with non-matching healing abutments: micro-CT analysis.

PURPOSE: To assess (i) the outcome of changing the horizontal-offset dimension on the peri-implant soft tissues and the crestal bone and (ii) the effect of different healing abutments (flared vs. straight) on the marginal peri-implant soft tissues and crestal bone. MATERIALS AND METHODS: Two-piece dental implants diameters of 3.5 and 4.5 mm were placed at least 1 mm subcrestal in five beagle dogs. Three different investigational groups: (i) 3.5-mm-diameter implant with narrow healing abutment (3.5N), (ii) 4.5-mm-diameter implant with narrow healing abutment (4.5N), and (iii) 3.5-mm-diameter implant with wide healing abutment (3.5W), were assessed. After 4 months of healing, the vertical distance from the marginal crestal bone (MB) to the implant shoulder (IS); the vertical distance from the IS to the first bone-to-implant contact; and the horizontal distance of bone ingrowth on the implant platform were measured with a high-resolution micro-CT (Xradia MicroXCT-200 system). RESULTS: Implants with a narrow healing caps showed an interproximal MB located between 0 and 1 mm above the implant shoulder, while the 3.5W group exhibits a mean value -0.50 mm. As all implants in group 3.5N presented a fBIC located at the level of the IS. For the 4.5N group, the mean fBIC-IS distance was -0.52 mm apically to the IS. For the 3.5WC group, the mean fBIC-IS distance was -1.42 mm. Horizontal bone apposition was only observed for the 3.5N group and the 4.5N group. CONCLUSION: The dimension of the horizontal offset would play a minimal role in reducing bone remodeling, whereas the configuration of the transmucosal component would directly influence marginal bone remodeling.

Narrow-Diameter versus Standard-Diameter Implants and Their Effect on the Need for Guided Bone Regeneration: A Virtual Three-Dimensional Study.

PURPOSE: Narrow-diameter implants (NDIs) are proven treatment options for completely edentulous patients with severely resorbed alveolar ridges. The aim of this study was to evaluate virtually whether or not the implant diameter affects the need for ridge augmentation in edentulous patients, using a 3D planning software program. MATERIALS AND METHODS: Existing cone beam CT scans of 200 outpatients (100 maxillae, 100 mandibles) were selected, and treatment was planned in a virtual 3D planning software program with either 3.3 mm-diameter implants (test group) or 4.1 mm-diameter implants (control group). Statistical analysis was performed. RESULTS: A total of 1,760 implants were virtually planned (880 implants each for test and control groups). Overall, significantly associated with the absence or need for ridge augmentation as compared with need for ridge augmentation (p < .0001). Use of the 3.3 mm-diameter implants increased the odds ratio for ridge augmentation being unnecessary by 2.2 (95% confidence interval) relative to the 4.1 mm-diameter implants. CONCLUSIONS: Use of NDIs was able to provide a statistically significant reduction in need for bone grafting among completely edentulous patients. More clinical longitudinal studies are necessary to confirm the long-term success of their use.

Implant-prosthodontic classification of the edentulous jaw for treatment planning with fixed rehabilitations.

PURPOSE: This study aimed to develop a classification of edentulous jaws for use as a diagnostic tool during implant-prosthodontic treatment planning. MATERIALS AND METHODS: The morphology of 200 fully edentulous alveolar ridges (100 maxillae, 100 mandibles) was assessed with cone beam computed tomography. Generic implants (length: 8 mm; diameter: 4.1 mm) were used. To develop the classification system, the feasibility of virtually placing the implants without vertical ridge augmentation was considered. Potential implant sites were evaluated in terms of ridge width and described as either type A (no horizontal augmentation required) or type B (horizontal augmentation required). A descriptive statistical analysis of subjects' age, sex, and arch classification was performed. RESULTS: In total, 880 implants were virtually planned. Based on alveolar ridge height, four arch patterns were identified (C1 to C4), providing a basis for prosthodontic planning with either removable or fixed implant-supported restorations. The frequencies of each category were as follows: C3 (n = 62, 62%), C4 (n = 16, 16%), C2 (n = 12, 12%), and C1 (n = 10, 10%) for the maxilla and C3 (n = 36, 36%), C4 (n = 31, 31%), C1 (n = 24, 24%), and C2 (n = 9, 9%) for the mandible. CONCLUSION: The proposed classification of the edentulous arch represents a useful tool for communication between clinicians when planning implant-supported rehabilitations.

Surgical and prosthetic management of ridge deficiency for an implant-supported restoration in the esthetic zone.

This clinical report presents the surgical and prosthetic management of a patient with complex needs involving anterior implants. After extraction and ridge augmentation, unexpected ridge resorption occurred. Two implants were placed in conjunction with an allograft skin material. Upon healing, 2 additional soft tissue augmentation procedures were performed with autologous pedicle connective tissue grafts to correct the residual ridge deficiency. At the second stage surgery, a modified flap approach was used to further enhance the soft tissue volume and contour. Definitive implant-supported splinted crowns with minimal interproximal pink ceramic material were provided.

The incidence of membrane perforation during sinus floor elevation using sonic instruments: a series of 40 cases.

This study reports the incidence of complications and sinus membrane perforations when using sonic instruments to prepare the lateral window osteotomy for maxillary sinus augmentation. The charts of 33 consecutive patients (40 sinuses) were reviewed. Sinus membrane perforations were reported in 7 cases (17.5% of procedures), with 3 perforations occurring during preparation of the osteotomy window (7.5% of procedures). Postoperatively, 2 cases of sinus infection (5%) and 2 cases of flap dehiscence (5%) were recorded. This study demonstrates that elevation of the sinus floor with a combination of hand and sonic instruments is feasible and safe, with a limited incidence of complications.

Loss of pulp vitality after maxillary sinus augmentation: a surgical and endodontic approach.

BACKGROUND: Maxillary sinus augmentation is a routine procedure performed in implant dentistry in cases with sinus pneumatization. This study presents a series of clinical cases in which tooth devitalization occurred in conjunction with sinus augmentation. METHODS: In the three cases presented, a sinus-lift procedure was performed that resulted in devitalization of the adjacent teeth. Patients were referred to an endodontist for evaluation and treatment. Vitality of the teeth was determined by the use of a cold test, electric pulp test, and cavity test. The pulp was considered to be necrotic if the tests were negative. RESULTS: In this case series, loss of pulp vitality of two maxillary left second premolars and one maxillary left first molar occurs after sinus-augmentation procedures. The devitalized teeth were free of caries. In one case, two amalgam restorations were present. CONCLUSION: Pulp necrosis may occur in conjunction with a sinus-lift procedure in cases when an adjacent root is in close proximity to the sinus floor and the sinus membrane is elevated over the root apex.

Morphology of bone particles after harvesting with 4 different devices.

INTRODUCTION: Autogenous bone is routinely used for regeneration of osseous defects around teeth and implants, and different instruments are available for bone harvesting. OBJECTIVES: The purpose of this study was to describe the morphology of bone particles after harvesting with 4 different instruments. MATERIALS AND METHODS: Bone particles were harvested from fresh cow ribs with 2 different types of back action chisels, a safescraper and a sonic device. The samples were examined morphologically using light microscopy and scanning electron microscopy. RESULTS: The bone particles after the back action chisel I had an appearance similar to "pencil shavings." With the back action chisel II, they were like thin paper with an "accordion bellows" appearance. After removal with the safescraper, they had an irregular shape (with an irregular surface) resembling "crushed stone." Finally, the appearance of the bone particles obtained with the sonic device was homogenous, condensed and continuous, and had a "seaweed" appearance. CONCLUSIONS: Harvesting of bone particles with 4 different devices produce distinctly difference sizes and shapes, which may influence the results of grafting procedures.

Sonosurgery for atraumatic tooth extraction: a clinical report.

The preservation of an intact labial plate during tooth extraction is a critical determinant of whether an immediate implant can be placed and is also an important predictor of the esthetic result. The purpose of this clinical report was to present a method for atraumatic tooth extraction by using an air-driven sonic instrument with specially designed inserts. This surgical technique provides the clinician with an efficient method for atraumatic tooth extraction and preservation of an intact labial plate.

The presence of the mandibular incisive canal: a panoramic radiographic examination.

PURPOSE: The mandibular incisive canal (MIC) is the anterior extension of the mandibular canal and its presence is of interest in surgical procedures in the chin region. The aim of this study was to investigate the presence of a MIC in panoramic radiographs (OPGs). METHODS: One thousand forty-five OPGs were randomly chosen from patient population. The data collected included patient characteristics and MIC presence/absence according to the type of the dentition. Measurements (in mm) were performed evaluating the following: (A) minimum and (B) maximum distance from the alveolar ridge; (C) thickness and (D) length of the canal; and (E) distance (in bilateral cases) between the canals. RESULTS: The MIC was found in 2.7% of the patients. CONCLUSIONS: This study demonstrates the frequency of the MIC in OPGs and suggests that this anatomical structure should be considered to prevent injury during surgery.

Maxillary sinus augmentation with a sonic handpiece for the osteotomy of the lateral window: a clinical report.

Several techniques have been proposed to manage patients with insufficient bone height for implant placement in the posterior maxilla. The lateral approach to sinus elevation is a successful procedure, with percentages of success close to 100%. Unfortunately, a frequent complication encountered during sinus elevation procedure is perforation of the Schneiderian membrane. In this clinical report, the authors present the application of a diamond coated sonic tip and an air-driven sonic instrument, commonly used in prosthodontics for the preparation of the lateral window osteotomy during sinus augmentation procedures.