Effect of Anchor-Guiding Sleeve Length on the Accuracy of Computer-Guided Flapless Implant Surgery.

The objective of this study was to evaluate the effect of anchor-guiding sleeve length on the accuracy of computer-guided flapless implant surgery in edentulous cases. Twelve identical polyurethane edentulous mandibular models were equally divided into short and long anchor-guiding sleeve groups based on the type of anchor-guiding sleeve. After implant placement and scan body connections, digital impressions were taken using the intraoral scanner. Using the software's measurement function, the deviation parameters between the planned and actual position of the placed implants were calculated and compared using the Mann-Whitney U test. In the short anchor-guiding sleeve group, the median angular deviation was 4.05° (range, 2.87°-7.55°). The median linear deviation was 1.17 mm (range, 0.24-2.17 mm) for the implant apex and 0.82 mm (range, 0.43-1.67 mm) for the implant shoulder. The median deviation of the depth was 0.31 mm (range, 0.20-0.79 mm). In the long anchor-guiding sleeve group, the median angular deviation was 2.70° (range, 1.77°-4.08°). The median linear deviation was 0.88 mm (range, 0.21-1.77 mm) for the implant apex and 0.63 mm (range, 0.11-1.97 mm) for the implant shoulder. The median deviation of the depth was 0.24 mm (range, 0.09-0.53 mm). There were significant differences between the 2 groups in the angular and linear deviations at the implant apex and the shoulder and depth deviation. The accuracy of the muco-supported surgical guide was improved using the long anchor-guiding sleeve, thus providing more accurate flapless implant placement in edentulous models. However, model experiments do not always produce predictable and possible uncontrolled cause-and-effect outcomes under natural clinical conditions. Therefore, further in vivo investigations are required to determine whether the results of this study are consistent with clinical findings.

Digital workflow for fabricating a verification device for an all-on-4 abutment: A dental technique.

The all-on-4 implant concept has been used to overcome anatomic limitations and has been reported to have high success rates. A verification device is commonly used to transfer the position of the angled distal abutment accurately. This article describes a digital workflow for fabricating a verification device to position the angled distal abutment with a hexagon connection during computer-guided flapless surgery.

Immediate nonfunctional loading of implants placed simultaneously using computer-guided flapless maxillary crestal sinus augmentation with bone morphogenetic protein-2/collagen matrix.

BACKGROUND: Immediate loading has shown positive results for total, partial, or single edentulism. The effects of BMP-2 addition to graft materials on bone formation and implant stability in the early stages of healing have rarely been studied, especially in patients with severely atrophic maxillae. PURPOSE: To evaluate the effects of simultaneously placed immediate non-functional loaded implants and bone morphogenetic protein-2 (BMP-2)-loaded Bio-Oss collagen, on bone formation and implant stability during the early healing stages of patients with a severely atrophic posterior maxilla using crestal approach. MATERIALS AND METHODS: Thirty-three cases presenting posterior maxillary residual alveolar bone height of 1-3 mm were evaluated. Flapless crestal sinus augmentation surgery was performed using BMP-2-loaded Bio-Oss collagen, with non-functional implants immediately loaded after surgery. The bone height was assessed using preoperative and postoperative cone beam computed tomography (CBCT). Bone density of the sinus graft sites and implant stability (after 3 months) were evaluated using postoperative CBCT scans and Periotest, respectively. The periodontal parameters and marginal bone loss around the implant were checked after 37.3 months of final prosthesis. RESULTS: The survival rate of the implants was 100% and the gingiva around the implants remained healthy. All implants remained integrated, and all sinus grafts showed radiographic bone formation. The results indicated high level of bone density and good implant stability, showing minimal marginal bone loss after 37.3 months. CONCLUSION: This technique could be used in the posterior maxillary region exhibiting poor bone quantity.

Digital Workflow for Computer-Guided Implant Surgery in Edentulous Patients with an Intraoral Scanner and Old Complete Denture.

A double-scan procedure is commonly performed in the process of fabricating an implant surgical template; however, this entails the disadvantage of recording 2 cone beam computed tomography (CBCT) scans requiring additional time, effort, and costs. The purpose of this article is to introduce a digital protocol to acquire adequate preoperative diagnostic information for a fully edentulous patient, using the existing complete denture with a metal framework, an intraoral scanner, and CBCT.

Accuracy of computer-guided implant placement in anterior regions.

STATEMENT OF PROBLEM: Implant placement in the anterior regions is often challenging because of limited space and bone volume availability. PURPOSE: The purpose of this clinical study was to investigate the accuracy of computer-guided surgery with a long drill key to place implants in the anterior regions. MATERIAL AND METHODS: Computer-guided implant surgery was performed for 32 participants requiring implants in anterior regions. The procedure involved using a 12-mm-long drill key to guide the 2.0-mm-diameter drill. Deviations between the planned and actual implant positions were evaluated by using cone beam computed tomography (CBCT) scans obtained before and after surgery. A t test was used for comparisons between the planned and placed implants and to determine the influence of the arch (maxilla/mandible) and time (immediate/delayed) on accuracy. RESULTS: A total of 40 implants (20 implants in the maxilla and 20 implants in the mandible) were placed. The mean linear deviation was 0.46 mm (range, 0 to 1.15 mm) for the implant shoulder and 0.67 mm (range, 0.14 to 1.19 mm) for the implant apex. The mean angular deviation was 1.40 degrees (range, 0.30 to 2.57 degrees). The mean depth deviation was 0.15 mm (range, 0.10 to 0.82 mm). CONCLUSIONS: This clinical study showed that the accuracy of computer-guided implant placement may be enhanced by using a long drill key and may thus enable more accurate implant placement in anterior regions.

Crestal Sinus Augmentation in the Presence of an Antral Pseudocyst.

PURPOSE: Antral pseudocysts classically have a well-defined, hyperdense, unilocular, dome-shaped appearance in radiographs. The best therapeutic approach for treating these cysts in the context of sinus floor augmentation remains controversial. This article presents a new technique that allows both sinus membrane elevation and cyst removal through a crestal approach in patients with pseudocysts in the maxillary sinus. MATERIALS AND METHODS: The technique combined aspiration of the cysts during sinus floor elevation with a sinus augmentation procedure using a hydraulic sinus elevation system. Aspiration of the cyst fluid was performed through the crestal osteotomy site after sinus floor elevation. RESULTS: Two patients showed a significant amount of bone formation around the implant at the sinus floor without evidence of a recurrent cyst after the procedure. CONCLUSIONS: The technique allows the minimally invasive removal of antral pseudocysts at the time of sinus grafting and simultaneous implant placement, preserving the integrity of the sinus membrane.

Digital Workflow for Computer-Guided Implant Surgery in Edentulous Patients: A Case Report.

PURPOSE: The purpose of this article was to describe a fully digital workflow used to perform computer-guided flapless implant placement in an edentulous patient without the use of conventional impressions, models, or a radiographic guide. MATERIALS AND METHODS: Digital data for the workflow were acquired using an intraoral scanner and cone-beam computed tomography (CBCT). The image fusion of the intraoral scan data and CBCT data was performed by matching resin markers placed in the patient's mouth. RESULTS: The definitive digital data were used to design a prosthetically driven implant position, surgical template, and computer-aided design and computer-aided manufacturing fabricated fixed dental prosthesis. CONCLUSION: The authors believe this is the first published case describing such a technique in computer-guided flapless implant surgery for edentulous patients.

Titanium-Silver Alloy Miniplates for Mandibular Fixation: In Vitro and In Vivo Study.

PURPOSE: Titanium (Ti) alloys have received considerable attention as materials for oral and maxillofacial surgery, which require high mechanical strength, osteosynthesis, and biocompatibility. The objective was to implant miniplates fabricated from commercially pure Ti (CP Ti) and newly developed Ti-silver (Ag) alloy in fractured mandibles of adult dogs after preliminary mechanical and biological characterization. MATERIALS AND METHODS: The surface characteristics, biocompatibility, and pre-osteoblast adhesion and proliferation of CP Ti (grade 3) and Ti-Ag (2 at% Ag) alloys were evaluated. Next, the bending strength of 6- and 8-hole miniplates fabricated from CP Ti and Ti-Ag was compared according to ISO (International Organization for Standardization) 9585. Six-hole miniplates were implanted for 12 weeks in fractured mandibles of adult dogs. The Ag ion concentration in each alloy and implanted bone block with soft tissue was measured by inductively coupled plasma mass spectroscopy after euthanasia according to ISO 10993-12. RESULTS: Precipitated Ag was detected in Ti-Ag by alpha- and beta-phase Ti in x-ray powder diffraction. The biocompatibility with pre-osteoblasts of Ti-Ag and CP Ti was comparable in terms of cytotoxicity, cell adhesion, and proliferation (P > .05). Ti-Ag miniplates had up to 3-fold greater bending strength than CP Ti miniplates (P < .05). An in vivo study showed that CP Ti and Ti-Ag miniplates had comparable soft and hard tissue regeneration ability (P > .05). Ag ions were detected in Ti-Ag alloys and applied mandible blocks. CONCLUSIONS: The results of this study suggest that Ti-Ag alloys can be used to produce miniplates with high mechanical properties, as well as considerable biocompatibility, osteosynthesis ability, and Ag ion-release properties. Further studies, including preclinical investigations, are required to enable clinical use of Ti-Ag bone plates.

Vertical ridge augmentation using xenogenous bone blocks: a comparison between the flap and tunneling procedures.

PURPOSE: Previous studies have shown that the subperiosteal tunneling procedure in vertical ridge augmentation accelerates healing after grafting and prevents graft exposure, with minor postoperative complications. It is conceivable that new bone formation would be greater with the tunneling procedure than with the flap procedure, because the former is minimally invasive. This hypothesis was tested in this study by comparing new bone formation between the flap and tunneling procedures after vertical ridge augmentation using xenogenous bone blocks in a canine mandible model. MATERIALS AND METHODS: Two Bio-Oss blocks were placed on the edentulous ridge in each side of the mandibles of 6 mongrel dogs. The blocks in each side were randomly assigned to grafting with a flap procedure (flap group) or grafting with a tunneling procedure (tunneling group). RESULTS: The mean percentage of newly formed bone within the block was 15.3 ± 6.6% in the flap group and 46.6 ± 23.4% in the tunneling group. CONCLUSION: Based on data presented in this study, when a tunneling procedure is used to place xenogenous bone blocks for vertical ridge augmentation, bone formation in the graft sites is significantly greater than when a flap procedure is used.

Simultaneous sinus lift and implantation using platelet-rich fibrin as sole grafting material.

Recently, several authors have shown that simultaneous sinus lift and implantation using autologous platelet-rich fibrin as the sole filling material is a reliable procedure promoting bone augmentation in the maxillary sinus. The aim of this study was to examine the effect of simultaneous sinus lift and implantation using platelet-rich fibrin as the sole grafting material on bone formation in a canine sinus model. An implant was placed after sinus membrane elevation in the maxillary sinus of six adult female mongrel dogs. The resulting space between the membrane and sinus floor was filled with autologous platelet-rich fibrin retrieved from each dog. The implants were left in place for six months. Bone tissue was seen at the lower part of the implants introduced into the sinus cavity. The height of the newly formed bone around the implants ranged from 0 mm to 4.9 mm (mean; 2.6 ± 2.0 mm) on the buccal side and from 0 mm to 4.2 mm (mean; 1.3 ± 1.8 mm) on the palatal side. The findings from this study suggest that simultaneous sinus lift and implantation using platelet-rich fibrin as sole grafting material is not a predictable and reproducible procedure, especially with respect to the bone formation around the implants in the sinus cavity.

The effect of guided flapless implant procedure on heat generation from implant drilling.

The objective of this study was to evaluate the heat generation in vitro during the flapless drilling procedure using surgical drill guides. Ten resin models with bilateral edentulous tooth spaces in the first and second molars in the mandible were used in this study. On one side of the mandible, drilling was performed with a flapless approach using a surgical drill guide. On the other side of the mandible, drilling was performed with a flap approach. The temperature changes were measured during final drilling by thermocouples. The mean maximum temperatures during drilling with guided flapless procedures were 29.5 °C and 32.6 °C at the depths of 3 and 6 mm, respectively, whereas for flap procedures they were 29.4 °C and 31.3 °C. There was no statistically significant difference between the groups. These findings suggest that drilling with external irrigation in an up-and-down pumping motion may not lead to a significant increase the bone temperature during a flapless procedure using surgical drill guides.

A comparative study of the regenerative effect of sinus bone grafting with platelet-rich fibrin-mixed Bio-Oss® and commercial fibrin-mixed Bio-Oss®: an experimental study.

Anorganic bovine bone (Bio-Oss®) particles are one of the most popular grafting materials. The particles are often mixed with platelet-rich fibrin (PRF) or a commercial fibrin (Tisseel®) to form a mouldable graft material. The objective of this study was to compare the potentials of PRF-mixed Bio-Oss® and Tisseel®-mixed Bio-Oss® to enhance bone regeneration in a canine sinus model. Six mongrel dogs were used in this study. After elevating the sinus membrane in both maxillary sinus cavities, an implant was placed into the sinus cavity. In one of the sinus cavities, the PRF/Bio-Oss® composite was grafted, and the Tisseel®/Bio-Oss® composite was grafted in the other sinus cavity. After a 6 month healing period, bone formation in the graft sites and bone-implant contact were evaluated. The mean osseointegration rate was 43.5 ± 12.4% and new bone formation rate 41.8 ± 5.9% in the PRF/Bio-Oss® composite sites. In the Tisseel®/Bio-Oss® composite sites they were 30.7 ± 7.9% and 31.3 ± 6.4%. There were statistically significant differences between the groups. The findings from this study suggest that when platelet-rich fibrin is used as an adjunct to Bio-Oss® particles for bone augmentation in the maxillary sinus, bone formation in the graft sites is significantly greater than when Tisseel® is used.

Minimally invasive ridge augmentation using xenogenous bone blocks in an atrophied posterior mandible: a clinical and histological study.

PURPOSE: Although various techniques for the treatment of an atrophic alveolar ridge have been described in the literature, these procedures have increased the morbidity and discomfort for the patient. The purpose of this study was to evaluate histological and clinical results in 9 patients who underwent a subperiosteal tunneling procedure with a Bio-Oss block onlay graft in an atrophic area of the mandible. PATIENTS AND METHODS: Nine months after grafting, at the time of dental implantation, biopsy samples were taken from the grafted areas of 9 patients and were analyzed histologically. RESULTS: New bone formation through the bovine bone block was observed consistently in the 9 cases. There was direct deposition of bone on the surface of the graft material. CONCLUSION: The results of this study indicated that ridge augmentation using a subperiosteal tunneling procedure with Bio-Oss bone blocks might be useful for implant placement in the atrophic alveolar ridges.

Flapless implant surgery using a mini-incision.

BACKGROUND: Traditional flapless implant surgery using a soft tissue punch device requires a circumferential excision of keratinized tissue at the implant site. A new flapless implant technique that can submerge implant fixtures is needed. PURPOSE: This article describes a flapless implant surgery method using a mini-incision and compares the effects of soft tissue punch and mini-incision surgery on both the amount of osseointegration and the bone height around the implants using a canine mandible model. MATERIALS AND METHODS: Bilateral, edentulated, flat alveolar ridges were created in the mandibles of six mongrel dogs. After a 3-month healing period, two implants were placed on each side of the mandible using either soft tissue punch or mini-incision procedures. After an additional 3-month healing period, a second stage surgery and transmucosal abutment attachment was performed for mini-incision implant cases. Following a 2-month healing period, the dogs were sacrificed to evaluate the osseointegration and bone height around the implants. RESULTS: Average bone height was 9.6 ± 0.4 mm in the soft tissue punch group and 9.8 ± 0.3 mm in the mini-incision group (p > .05). Average osseointegration was 70.4 ± 6.3% in the soft tissue punch group and 71.2 ± 7.1% in the mini-incision group (p > .05). No significant differences were noted between the two groups in vertical alveolar ridge height or bone/implant contact. CONCLUSIONS: Our findings support the clinical use of mini-incision implant surgery at sites where implants need to be protected below the soft tissue during the early phase of healing, particularly for patients with poor bone quality and/or low primary implant stability.

Effects of flapless implant surgery on soft tissue profiles: a prospective clinical study.

BACKGROUND: Flapless implant surgery has been suggested as a suitable treatment modality for the preservation of soft tissue after implant placement. PURPOSE: The purpose of this study was to determine the extent of soft tissue profile changes around implants after flapless implant surgery. MATERIALS AND METHODS: A total of 44 patients received 76 implants using a flapless implant procedure. The marginal level of the peri-implant soft tissue was evaluated using dental casts 1 week, 1 month, and 4 months after implant placement. RESULTS: The mean soft tissue levels around implants showed 0.7 ± 0.3 mm of coronal growth 1 week after surgery. At 1 month, the levels were 0.2 ± 0.2 mm coronal growth and at 4 months, the values were 0.0 ± 0.3 mm. Soft tissue profiles assessed 4 months after flapless implant placement were similar to profiles assessed immediately before implant placement. CONCLUSION: Flapless implant surgery is advantageous for preserving mucosal form surrounding dental implants.

A 1-year prospective clinical study of soft tissue conditions and marginal bone changes around dental implants after flapless implant surgery.

BACKGROUND: Despite several reports on the clinical outcomes of flapless implant surgery, limited information exists regarding the clinical conditions after flapless implant surgery. OBJECTIVE: The objective of this study was to evaluate the soft tissue conditions and marginal bone changes around dental implants 1 year after flapless implant surgery. STUDY DESIGN: For the study, 432 implants were placed in 241 patients by using a flapless 1-stage procedure. In these patients, peri-implant soft tissue conditions and radiographic marginal bone changes were evaluated 1 year after surgery. RESULTS: None of the implants were lost during follow-up, giving a success rate of 100%. The mean probing depth was 2.1 mm (SD 0.7), and the average bleeding on probing index was 0.1 (SD 0.3). The average gingival index score was 0.1 (SD 0.3), and the mean marginal bone loss was 0.3 mm (SD 0.4 mm; range 0.0-1.1 mm). Ten implants exhibited bone loss of >1.0 mm, whereas 125 implants experienced no bone loss at all. CONCLUSION: The results of this study demonstrate that flapless implant surgery is a predictable procedure. In addition, it is advantageous for preserving crestal bone and mucosal health surrounding dental implants.

Comparison of flap and flapless procedures for the stability of chemically modified SLA titanium implants: an experimental study in a canine model.

BACKGROUND: Flapless implant surgery has been shown to accelerate recovery and increase the vascularity of the peri-implant mucosa after implant placement. OBJECTIVE: The aim of this study was to compare dental implant stabilization patterns between flap and flapless implant surgeries over the first 8 weeks after implant placement. STUDY DESIGN: In 6 mongrel dogs, bilateral, edentulated, and flat alveolar ridges were created in the mandible. After 3 months of healing, 2 implants (Straumann SLA-active) were placed in each side of the mandible using either a flap or flapless procedure. The implant stability quotient (ISQ) that was obtained from Osstell Mentor was measured at the time of implantation and weekly over the first 8 weeks after implant placement. RESULTS: Implants stabilized more quickly without flap elevation than with flap elevation. For flapless implants, an increase in stability occurred after 2 weeks without a period of decreasing stability. However, for flap implants, a shift in implant stability from decreasing stability to increasing stability occurred after 2 weeks. CONCLUSION: In the canine model, flapless surgical placement of implants may increase the initial stability of implants compared with implants placed after the reflection of the mucoperiosteal flap.

A comparative study on the extractions of partially impacted mandibular third molars with or without a buccal flap: a prospective study.

PURPOSE: The present report describes a flapless extraction method for partially impacted mandibular third molars and compares the effects of flap and flapless extractions of the teeth in terms of postoperative pain, swelling, and pocket depth of the second molar. PATIENTS AND METHODS: A prospective study was performed of 27 patients who underwent bilateral extraction of partially impacted mandibular third molars. Two molars in the same patient were extracted on each side, either with or without a buccal flap. RESULTS: The postoperative pain, swelling, and pocket depth of the second molar were all significantly greater on the side that underwent flap extraction than on the side that underwent flapless extraction (P < .05). CONCLUSIONS: Our results support the clinical use of flapless extractions when the distal surface of the crown is completely anterior to the anterior border of the mandibular ramus and the occlusal surface of the impacted tooth is level or nearly level with the occlusal plane of the second molar.

Effects of soft tissue punch size on the healing of peri-implant tissue in flapless implant surgery.

OBJECTIVE: In an attempt to help produce guidelines for the use of soft tissue punches, this animal study was undertaken to examine the effects of soft tissue punch size on the healing of peri-implant tissue in a canine mandible model. STUDY DESIGN: Bilateral, edentulous, flat alveolar ridges were created in the mandibles of 6 mongrel dogs. After a 3-month healing period, 3 fixtures (diameter 4.0 mm) were placed on each side of the mandible using 3-mm, 4-mm, or 5-mm soft tissue punches. After subsequent healing periods of 3 weeks and 3 months, the peri-implant mucosa was evaluated using clinical, radiologic, and histometric parameters, which included gingival index, bleeding on probing, probing pocket depth, marginal bone loss, and vertical dimension measurements of the peri-implant tissues. RESULTS: The results obtained showed significant differences (P < .05) between the 3-mm, 4-mm, and 5-mm tissue punch groups for the length of the junctional epithelium, probing depth, and marginal bone loss at both 3 weeks and 3 months after implant placement. When the mucosa was punched with a 3-mm tissue punch, the length of the junctional epithelium was shorter, the probing depth was shallower, and less crestal bone loss occurred than when using a tissue punch with a diameter >or=4 mm. CONCLUSIONS: The results show that the size of the soft tissue punch plays an important role in achieving optimal healing. The findings support the use of a tissue punch slightly narrower than the implant itself to obtain better peri-implant tissue healing around flapless implants.

Blood vessels of the peri-implant mucosa: a comparison between flap and flapless procedures.

OBJECTIVE: The vascularity of a peri-implant tissue is a very important parameter in the establishment and maintenance of healthy tissue after dental implant insertion. The purpose of this study was to compare the vascularity of the peri-implant mucosa between flap and flapless implant surgeries by using a canine mandible model. STUDY DESIGN: In six mongrel dogs, bilateral, edentulated, and flat alveolar ridges were created in the mandible. After 3 months of healing, 2 implants were placed in each side by either flap or flapless procedure. After another healing period of 3 months, biopsies were obtained, prepared for light microscopy, and exposed to morphometric measurements. RESULTS: The supracrestal connective tissue lateral to the implant was found to be more richly vascularized in the flapless group than in the flap group. CONCLUSION: These results suggest that the flapless procedure may increase the vascularity of the peri-implant mucosa.