Faculty Bibliography

PURPOSE: Nitrite is a stable end-product of nitric oxide oxidation. The aim of the present study was to quantitatively analyze peri-implant sulcular fluid (PISF) nitrite levels in a longitudinal study design to evaluate the potential changes in nitric oxide metabolism in relation to the clinical status of the peri-implant site and the loading style of the dental implants. MATERIALS AND METHODS: A total of 34 implants, either early loaded (EL) or delayed loaded (DL), in 17 patients were followed up for a period of 18 months. Clinical parameters were recorded, PISF samples were obtained, and PISF nitrite levels were spectrophotometrically determined. Clinical measurements and nitrite analysis were repeated at 1, 3, 6, 9, 12, and 18 months. RESULTS: Despite the gradual decrease in clinical parameters, fluctuations in PISF total nitrite levels were observed during follow-up. The pattern of nitric oxide metabolism, as reflected by PISF nitrite levels, also demonstrated differences between EL and DL implants that diminished toward the end of the experimental period. DISCUSSION: Although the presence of clinical and subclinical gingival inflammation contributes to the PISF total nitrite levels, nitric oxide metabolism is also associated with healing and bone remodeling, and the pattern of loading seemed to have an impact on nitric oxide production at dental implant sites. CONCLUSION: Nitric oxide production at dental implant sites seems to be tightly regulated to enable the maintenance of peri-implant bone.

BACKGROUND: The original Branemark protocol for dental implant treatment was based on submerged healing prior to loading. In recent years, immediate/early functional loading has been reported to be possible with high success for various indications including two splinted mandibular implants supporting an overdenture. However, there are a limited number of studies regarding the early loading protocol for two unsplinted mandibular implants supporting an overdenture. METHODS: A total of 26 edentulous patients were treated with two unsplinted dental implants supporting mandibular overdentures. All implants were placed in the canine regions of each mandible according to the one-stage surgery. For the test group, overdentures were connected 1 week after surgery, and for the control group, overdentures were connected 3 months after surgery. Peri-implant parameters were recorded 1, 6, 12, 18, and 24 months after surgery. Marginal bone levels were evaluated at implant placement and after 6, 12, 18, and 24 months. Clinical stability measurements were performed at surgery, and after 3, 6, 12, 18, and 24 months. RESULTS: No implant from either group was lost during 2 years. Clinical peri-implant parameters, clinical implant stability measurements, and marginal bone resorptions showed no statistically significant differences between the two groups during 24 months. CONCLUSION: The results of this clinical trial suggest that the early loading approach of two dental implants supporting a mandibular overdenture does not jeopardize peri-implant soft tissue health, marginal bone resorption, and implant stability.

BACKGROUND: Flapless surgery requires penetration of the alveolar mucosa and bone without reflection of mucoperiosteal flaps. Do these techniques force gingival tissue or foreign materials into osteotomies? If so, do such tissues or materials interfere with osseointegration? A proof-of-principle study using a canine model attempted to answer these questions. METHODS: Five young adult Hound Labrador mongrel dogs received implants with a moderately roughened surface by anodic oxidation using flapless or conventional one-stage (control) surgery in contralateral jaw quadrants. The implants were placed into the osteotomies, and the international stability quotient (ISQ) was recorded using resonance frequency analysis. These measurements were repeated following a 3-month healing interval when the animals were euthanized, and implants and surrounding tissues were retrieved and processed for histologic analysis. RESULTS: The implants were stable upon insertion and demonstrated increased stability at 3 months without significant differences between surgical protocols. The histologic evaluation showed high bone-implant contact (flapless surgery: 54.7% +/- 8.4%; control: 52.2% +/- 13.0%; P >0.05) without evidence of gingival tissue or foreign body inclusions. There were no significant differences in marginal bone levels between the surgical protocols. Post-insertion and at 3 months, ISQ values depended on the amount of torque delivered. Immediately post-insertion, for every 1-unit increase in torque value, the ISQ increased by 0.3 (95% confidence interval: 0.1 to 0.4; P = 0.0043). Three months postoperatively, for every one-unit increase in torque the ISQ value decreased 0.2 (95% confidence interval: -0.4 to -0.1; P = 0.0012). The effect of torque on ISQ values was independent of treatment effects and remained significant after adjustment for treatment. CONCLUSIONS: The results suggest that implants placed without flap reflection remain stable and exhibit clinically relevant osseointegration similar to when implants are placed with flapped procedures. Greater torque at implant placement resulted in less implant stability at 3 months.

OBJECTIVES: The aim of this study was to compare the performance of two non-splinted implants used as retention for a mandibular overdenture when applying conventional or early loading protocols. MATERIAL AND METHODS: Twenty edentulous patients were treated with two unsplinted and non-submerged implants (15 mm long, TiUnite RP, Branemark System) in the anterior mandible. The patients were randomly allotted into two groups: (i) test group (Group A), in which the overdenture was connected 1 week after surgery, and (ii) control group (Group B), in which the overdenture was connected after 12 weeks of healing. Resonance frequency analyses (RFA) for implant stability measurements were performed at implant surgery and after 1, 3, 6, 9 and 12 months. Marginal bone levels were evaluated at implant surgery and after 6 and 12 months. RESULTS: No implant from either group was lost and all implants showed less than 1 mm of marginal bone resorption during the first year. The mean implant stability quotient (ISQ) values at implant surgery were 76.2+/-2.8 for Group A and 75.6+/-4.5 for Group B. The 12-month measurements showed 76.4+/-2.5 ISQ and 76.4+/-2.8 ISQ for Groups A and B, respectively. There were no statistically significant changes between or within the groups with time. There were no differences in marginal bone loss, which was on average 0.3 mm for both groups after 1 year. CONCLUSION: Although a limited number of patients were followed for 1 year only, the results of the present study indicate that early loading of two unsplinted 15 mm long implants with an overdenture does not negatively affect implant stability or marginal bone conditions when compared with implants subjected to 12 weeks of healing before loading.

PURPOSE: This clinical trial aimed to evaluate the outcomes of implant-supported mandibular overdentures (ISMOs) using 2 different loading protocols. MATERIALS AND METHODS: Two groups of 10 edentulous patients each were selected for the study. Each patient received 2 implants placed in the mandibular canine sites. After 1 week, ISMOs were delivered to the 10 patients in the test group, while conventional mandibular dentures were delivered to the 10 patients in the control group. The conventional prostheses were converted to ISMOs after 3 months. Treatment outcomes for the ISMOs were evaluated 1 year after implant surgery. RESULTS: The number of appointments and time needed for fabrication of ISMOs revealed statistically significant differences between the patient groups. The requirements for prosthodontic maintenance of ISMOs in the test group were higher than those in the control group; however, these differences were not statistically significant. The mean marginal bone resorption for each group was 0.3 mm after 1 year. CONCLUSION: The results of this clinical trial suggest that early loading of a specific length of implants used to support mandibular overdentures does not jeopardize treatment outcomes during the first year of service.

In this study, 19 patients were treated with 36 Branemark System MK III TiUnite implants in the maxilla. Definitive implant-supported single crowns were delivered to patients 6 weeks after implant placement. Clinical and radiographic parameters were recorded at baseline, and at 1, 2, and 3 years. Both implant and prosthesis success rates were 94% after 3 years. The average marginal bone loss was 0.97 mm after 3 years. The results of this study indicate that 6-week early loading of TiUnite surface implants in the maxilla was reliable and predictable for this patient population and may offer an alternative to the standard loading protocol.

OBJECTIVE: The aim of this study was to evaluate clinical and radiological outcomes of the unsplinted implants supporting mandibular overdenture when applying conventional or early loading protocols. MATERIAL AND METHODS: Twenty-six edentulous patients were treated with two unsplinted Branemark System implants supporting mandibular overdenture. There was a test group, in which the overdenture was connected 1 week after surgery, and a control group, in which the overdenture was connected 3 months after surgery. Peri-implant parameters were recorded 1, 6, and 12 months after surgery. Clinical stability measurements were performed at surgery, and after 3, 6, and 12 months. Marginal bone levels were evaluated at implant surgery, after 6, and after 12 months. RESULTS: No implant from either group was lost. Clinical peri-implant parameters, clinical stability measurements, and marginal bone resorptions showed no statistically significant differences between two groups during 12 months. CONCLUSION: The results of this study suggest that one-week of early loading protocol of two Branemark implants supporting mandibular overdenture does not compromise implant stability, marginal bone loss, and peri-implant soft-tissue health.

PURPOSE: The aim of the present study was to analyze the possible impact of clinical status, presence and severity of inflammation, and loading on nitric oxide (NO) metabolism around mandibular dental implants. MATERIALS AND METHODS: A total of 34 implants in 17 patients, loaded either early (EL) or after a delay (DL), were classified according to the presence and severity of clinical inflammation in the peri-implant sites. Clinical parameters were recorded, peri-implant sulcular fluid (PISF) samples were obtained, and PISF nitrite levels were spectrophotometrically determined. Clinical measurements and nitrite analysis were repeated at 1, 3, 6, and 9 months postloading at available sites. RESULTS: Compared to noninflamed sites, inflamed sites demonstrated higher mean total nitrite levels (P = .032) that tended to increase with the severity of inflammation at both EL and DL implants. At noninflamed sites, EL implants provided significantly higher PISF volume than DL implants (P = .001). At noninflamed sites, EL implants revealed higher total nitrite levels; on the contrary, at inflamed sites, DL implants revealed higher total nitrite levels. In general, nitrite levels demonstrated a pattern of decrease followed by an increase during follow-up. DISCUSSION: Increased NO production with the presence and the severity of inflammation supports the contribution of NO in the peri-implant inflammatory process. Loading is also likely to have an impact on NO metabolism, which suggests a role for NO in remodeling and adaptation of bone around dental implants. CONCLUSION: Besides the presence of inflammation, the severity of inflammation and loading also seem to have an impact on NO metabolism around dental implants.