Marginal Bone Stability Around Tapered, Platform-Shifted Implants Placed with an Immediately Loaded Four-Implant-Supported Fixed Prosthetic Concept: A Cohort Study.

PURPOSE: To longitudinally evaluate marginal bone remodeling around tapered, platform-shifted implants placed for total arch rehabilitation with fixed hybrid prostheses. MATERIALS AND METHODS: A retrospective cohort study was designed that evaluated radiographic data from patients undergoing implant surgical procedures with an immediately loaded four-implant-supported fixed prosthetic concept in a single clinic setting during a 36-month period. The primary outcome variable was the change in marginal bone levels during a 12- to 36-month follow-up postloading with the definitive prosthesis. All measurements were performed on matched and calibrated periapical radiographs obtained at: (1) the time of placement of the definitive prosthesis (baseline) versus (2) 12 to 36 months following definitive loading (follow-up). Other study variables, including duration of follow-up, implant position, maximum insertion torque, implant angulation, and implant diameter, were assessed for their association with changes in marginal bone levels. RESULTS: One hundred sixty-nine patients (n = 856 implants) with a mean age of 59.5 ± 10.5 years were included in this study. Two implants failed, resulting in a 99.8% overall survival rate (mean follow-up: 15.2 ± 4.8 months, range: 12 to 36 months). The radiographic mean bone levels at baseline and follow-up were 1.16 ± 0.71 mm (n = 805) and 1.31 ± 0.93 mm (n = 805), respectively. The mean marginal bone loss from baseline to follow-up was 0.14 ± 0.59 mm (n = 805). The duration of follow-up had no effect on the extent of marginal bone loss (P = .154). CONCLUSION: Within the limitations of this large-scale retrospective cohort study, it was concluded that the use of tapered, platform-shifted implants for total arch rehabilitation with the use of the All-on-Four protocol yields very favorable radiographic outcomes, at least after a minimum of 12 months in function.

Effect of a modified stepped osteotomy on the primary stability of dental implants in low-density bone: a cadaver study.

PURPOSE: The aim of this study was to examine the effect of an alternative surgical technique on endosseous dental implant stability parameters in Class D4 bone. Differences between insertion torque (IT) and implant stability quotient (ISQ) produced by a conventional osteotomy versus a modified stepped osteotomy were examined. Correlations between IT, density in Hounsfield units (HU), and ISQ were also examined. MATERIALS AND METHODS: Computed tomographic scans were taken of 16 cadaver heads to determine bone density at maxillary implant recipient sites, which ranged from 173.4 to 312.1 HU. Twenty-two implants were placed in sites with Misch Class D4 bone; control sites received 11 conventional osteotomies and test sites 11 modified stepped osteotomies. Maximum IT was recorded with an implant motor and confirmed with a torque driver, and ISQs were measured. Significant differences were analyzed with a Wilcoxon signed rank test, and correlations were analyzed with the Pearson test. RESULTS: The mean IT in the control group was 15.91 Ncm, and in the test group it was 26.82 Ncm. The modified stepped osteotomy had a significantly greater mean IT than the conventional osteotomy, but no significant difference in ISQ was found between groups. Pearson correlations showed a significant positive correlation between IT in the control and test groups. Significant correlations were found between ISQ and HU in the test group. No other significant correlations between HU, IT, and ISQ were found. CONCLUSION: Within the limits of this cadaver study, the modified stepped osteotomy resulted in significantly greater implant stability in terms of IT than the conventional osteotomy in soft bone. Significant correlations were found between the IT produced in the modified stepped osteotomy and bone density. No significant correlations were found between IT and ISQ.

Clinical evaluation of 262 osseointegrated implants placed in sites grafted with calcium phosphosilicate putty: a retrospective study.

Along with the widespread use of dental implants, regenerative procedures have become an indispensable tool for implant surgeons in managing residual ridges and the surrounding bone. Putty bone grafts have significantly superior handling characteristics in comparison to particulates. These include ease of placement, enhanced particle containment, and a viscous consistency that has allowed for unique delivery systems to be developed. The aim of this study was to report the clinical efficacy of calcium phosphosilicate (CPS) putty in a wide variety of indications related to implant reconstruction and to report the survival rate of implants placed in these grafted sites. The CPS putty was used as the graft material of choice. Treatments were categorized into following groups: extraction graft, extraction with immediate implant placement, all-on-four concept, peri-implantitis treatment, bone augmentation before implant placement, implant replacement graft, and grafting around implant placed in resorbed ridges. Included in the analysis were 65 patients (36 men, 29 women) with a mean age of 63 ± 12 years. In total, 262 implants were placed. Four implants were diagnosed with peri-implantitis and were treated as described in category 4, for a total of 266 grafted sites. Two implants from the extraction graft category and 3 implants from the all-on-four group were lost and replaced with successfully osseointegrated implants during a mean study follow-up period of 12.24 ± 2.32 months. The implant success rate at 1 year was 98.1% (257/262). Based on results of this large-scale, retrospective study we conclude that (1) the use of putty bone grafts can simplify bone-grafting procedures and reduce intraoperative time in various grafting indications, (2) this study verified the efficacy of a CPS putty bone graft biomaterial in a large array of implant-related surgical indications, and (3) implants placed in sites grafted with CPS putty yield very high survival rates.

Patient-related and financial outcomes analysis of conventional full-arch rehabilitation versus the All-on-4 concept: a cohort study.

BACKGROUND: Patient-related variables such as cost of treatment, length of the treatment period, and comfort provided by the interim prosthesis when treatment planning for full-arch rehabilitation are often neglected in dental publications. METHODS: Two patient cohorts were followed up longitudinally in this study: the "All-on-4 treatment concept group" and the "historical group." The number of implants, total treatment time, number of surgical procedures, number of sinus grafts, necessity for immediate provisional implants, adjusted cost associated for treatment in each group, and the quality of interim prosthesis were compared. RESULTS: The total adjusted cost for patients receiving All-on-4 treatment concept averaged at $42,422 ± 3860 (&OV0556;31,392 ± 2856), whereas the mean total adjusted cost for the historical group was $57,944 ± 20,198 (&OV0556;42,879 ± 2113) (P = 0.01). The difference in cost had a mean value of $7307 (&OV0556;5407) per jaw. Factors associated with complexity of treatment and patient comfort, such as the quality of interim prosthesis, number of surgeries, and duration of treatment time, all significantly favored the All-on-4 treatment concept group in comparison with conventional treatment modalities. CONCLUSIONS: When implant rehabilitation of the total jaw is sought, the All-on-4 treatment concept should be considered the least costly and least time consuming treatment option.

A new approach to the All-on-Four treatment concept using narrow platform NobelActive implants.

Although a number of approaches to implant-supported restoration of severely atrophic maxillae and mandibles have been developed, most of these treatments are costly and protracted. An exception is the All-on-Four concept, which uses only 4 implants to support an acrylic, screw-retained provisional prosthesis delivered on the day of implant placement, followed by a definitive prosthesis approximately 4 months later. After the introduction of a new implant design in 2008, a new protocol was developed for provisionally treating patients with severely atrophic jaws using the All-on-Four concept and 3.5-mm-diameter implants. This article describes that protocol and reports on the results of 227 implants after 1 to 3 years of follow-up. The cumulative survival rate was 98.7% at the end of 3 years, with a 100% prosthetic survival rate. Combining the 3.5-mm-diameter NobelActive implants with the All-on-Four concept promises to become a new standard of care for severely compromised patients.

Mandibular incisive canal: cone beam computed tomography.

PURPOSE: Panoramic radiography is often used to analyze the anatomical structure of the teeth, jaws, and temporomandibular joints. Cone beam computed tomography (CBCT) imaging allows multiple axial slices of the image to be obtained through these anatomical structures. The aim of this study was to assess CBCT compared with panoramic radiography to verify the presence, location, and dimensions of the mandibular incisive canal. MATERIALS AND METHODS: CBCT scan images and panoramic radiographs of 89 subjects were compared for the presence of the mandibular incisive canal, its location, size, and anterior-posterior length. The distance between the incisive canal and the buccal and lingual plate of the alveolar bone, and the distance from the canal to the inferior border of the mandible and the tooth apex were also measured. A paired t-test was used to calculate any significant difference between the two imaging techniques. RESULTS: Eighty-three percent of the CBCT scans showed the presence of the incisive canal, as did 11% of the panoramic radiographs. The range of the incisive canal diameter, as seen in the CBCT scans, was from 0.4 × 0.4 mm to 4.6 × 3.2 mm. The mean length of the canal was 7 ± 3.8 mm. The distance from the inferior border of the mandible to the canal was 10.2 ± 2.4 mm, and the mean distance to the buccal plate was 2.4 mm. The apex-canal distance (in dentate subjects) was 5.3 mm. CONCLUSION: The presence, location, and dimensions of the mandibular incisive canal are better determined by CBCT imaging than by panoramic radiography.

Repeatability of a dental shade-matching instrument when compared to traditional visual methods of shade evaluation.

Electronic shade-matching instruments are available for clinical use; however, their accuracy has not been established. This study evaluated a new electronic method of clinical shade matching compared to the standard visual method. The Vita Easyshade system, an electronic method of shade matching, was used on 40 subjects to measure the central region of each patient's maxillary left central incisor (tooth No. 9). Two visual evaluators with predetermined visual shade matching abilities selected a shade from the same area of tooth No. 9 for all subjects. Student's t-test, using a 95% score confidence interval (CI), was used to compare the two methods. The Vita Easyshade system was accurate 85% of the time in this in vivo study; however, the instrument was predictably accurate only 68-91% of the time at the 95% CI.

Measurement of clinicians' ability to hand torque dental implant components.

There is a varying degree of hand torque abilities using finger drivers among clinicians. Calibrating one's own abilities requires complicated instruments not readily available. This study evaluated a simple-to-use method that allows dental practitioners to have a quantifiable clinical assessment of relative torque ability using finger drivers to torque down dental implant components. A typodont that includes dental implants was mounted in a mannequin placed in a patient-reclined position. The subjects were asked to torque as tightly as they could a new healing abutment to an implant secured firmly in resin within the typodont. All participants wore moistened gloves when using a finger driver. The healing abutment was countertorqued using a certified precalibrated precision torque measurement device. The reading on the torque driver was recorded when the healing abutment disengaged. An average of torque values of dentists and dental students was calculated. Fifty subjects had an average maximum torque ability of 24 Ncm (male dentists: 28 Ncm; students: 22 Ncm; male students: 24 Ncm; female students: 19 Ncm). Maximum torque values for all participants ranged from 11 Ncm to 38 Ncm. There was no significant difference between groups. This study showed a varying degree of hand torquing abilities using a finger driver. Clinicians should regularly calibrate their ability to torque implant components to more predictably perform implant dentistry. Dental implant manufacturers should more precisely instruct clinicians as to maximum torque, as opposed to "finger tighten only".