Effects of implant design on marginal bone changes around early loaded, chemically modified, sandblasted Acid-etched-surfaced implants: a histologic analysis in dogs

A minimal marginal bone loss around implants during early healing has been considered acceptable. However, the preservation of the marginal bone is related to soft tissue stability and esthetics. Implant designs and surfaces were evaluated to determine their impact on the behavior of the crestal bone. The purpose of this study is to evaluate histologic marginal bone level changes around early loaded, chemically modified, sandblasted acid-etched-surfaced implants with a machined collar (MC) or no MC (NMC).

Biomechanical evaluation of the interfacial strength of a chemically modified sandblasted and acid-etched titanium surface

The functional capacity of osseointegrated dental implants to bear load is largely dependent on the quality of the interface between the bone and implant. Sandblasted and acid-etched (SLA) surfaces have been previously shown to enhance bone apposition. In this study, the SLA has been compared with a chemically modified SLA (modSLA) surface. The increased wettability of the modSLA surface in a protein solution was verified by dynamic contact angle analysis. Using a well-established animal model with a split-mouth experimental design, implant removal torque testing was performed to determine the biomechanical properties of the bone-implant interface. All implants had an identical cylindrical shape with a standard thread configuration. Removal torque testing was performed after 2, 4, and 8 weeks of bone healing (n = 9 animals per healing period, three implants per surface type per animal) to evaluate the interfacial shear strength of each surface type. Results showed that the modSLA surface was more effective in enhancing the interfacial shear strength of implants in comparison with the conventional SLA surface during early stages of bone healing. Removal torque values of the modSLA-surfaced implants were 8-21% higher than those of the SLA implants (p = 0.003). The mean removal torque values for the modSLA implants were 1.485 N m at 2 weeks, 1.709 N m at 4 weeks, and 1.345 N m at 8 weeks; and correspondingly, 1.231 N m, 1.585 N m, and 1.143 N m for the SLA implants. The bone-implant interfacial stiffness calculated from the torque-rotation curve was on average 9-14% higher for the modSLA implants when compared with the SLA implants (p = 0.038). It can be concluded that the modSLA surface achieves a better bone anchorage during early stages of bone healing than the SLA surface; chemical modification of the standard SLA surface likely enhances bone apposition and this has a beneficial effect on the interfacial shear strength.

Influence of a machined collar on crestal bone changes around titanium implants: a histometric study in the canine mandible

It has been shown that peri-implant crestal bone reactions are influenced by both a rough-smooth implant border in one-piece, non-submerged, as well as an interface (microgap [MG] between implant/abutment) in two-piece butt-joint, submerged and non-submerged implants being placed at different levels in relation to the crest of the bone. According to standard surgical procedures, the rough-smooth implant border for implants with a smooth collar should be aligned with the crest of the bone exhibiting a smooth collar adjacent to peri-implant soft tissues. No data, however, are available for implants exhibiting a sandblasted, large-grit and acid-etched (SLA) surface all the way to the top of a non-submerged implant. Thus, the purpose of this study is to histometrically examine crestal bone changes around machined versus SLA-surfaced implant collars in a side-by-side comparison.

Performance of dental implants after staged sinus floor elevation procedures: 5-year results of a prospective study in partially edentulous patients

OBJECTIVES: The aim of this prospective study was to evaluate the 5-year performance and success rate of titanium screw-type implants with the titanium plasma spray (TPS) or the sand-blasted, large grit, acid-etched (SLA) surface inserted in a two-stage sinus floor elevation (SFE) procedure in the posterior maxilla. MATERIAL AND METHODS: A total of 59 delayed SFEs were performed in 56 patients between January 1997 and December 2001, using a composite graft with autogenous bone chips combined with deproteinized bovine bone mineral (DBBM) or synthetic porous beta-tricalcium phosphate (beta-TCP). After a healing period averaging 7.75 months, 111 dental implants were inserted. After an additional 8-14-week healing period, all implants were functionally loaded with cemented crowns or fixed partial dentures. The patients were recalled at 12 and 60 months for clinical and radiographic examination. RESULTS: One patient developed an acute infection in the right maxillary sinus after SFE and did not undergo implant therapy. Two of the 111 inserted implants had to be removed because of a developing atypical facial pain, and 11 implants were lost to follow-up and were considered drop-outs. The remaining 98 implants showed favorable clinical and radiographic findings at the 5-year examination. The peri-implant soft tissues were stable over time; the mean probing depths and mean attachment levels did not change during the follow-up period. The measurement of the bone crest levels (DIB values) indicated stability as well. Based on strict success criteria, all 98 implants were considered successfully integrated, resulting in a 5-year success rate of 98% (for TPS implants 89%, for SLA implants 100%). CONCLUSION: This prospective study assessing the performance of dental implants inserted after SFE demonstrated that titanium implants can achieve and maintain successful tissue integration with high predictability for at least 5 years of follow-up in carefully selected patients.

Osseointegration of titanium implants functionalised with phosphoserine-tethered poly(epsilon-lysine) dendrons: a comparative study with traditional surface treatments in sheep

The aim of this study was to analyse the osseointegrative potential of phosphoserine-tethered dendrons when applied as surface functionalisation molecules on titanium implants in a sheep model after 2 and 8 weeks of implantation. Uncoated and dendron-coated implants were implanted in six sheep. Sandblasted and etched (SE) or porous additive manufactured (AM) implants with and without additional dendron functionalisation (SE-PSD; AM-PSD) were placed in the pelvic bone. Three implants per group were examined histologically and six implants were tested biomechanically. After 2 and 8 weeks the bone-to-implant contact (BIC) total values of SE implants (43.7 ± 12.2; 53.3 ± 9.0 %) and SE-PSD (46.7 ± 4.5; 61.7 ± 4.9 %) as well as AM implants (20.49 ± 5.1; 43.9 ± 9.7 %) and AM-PSD implants (19.7 ± 3.5; 48.3 ± 15.6 %) showed no statistically significant differences. For SE-PSD and AM-PSD a separate analysis of only the cancellous BIC demonstrated a statistically significant difference after 2 and 8 weeks. Biomechanical findings proved the overall increased stability of the porous implants after 8 weeks. Overall, the great effect of implant macro design on osseointegration was further supported by additional phosphoserine-tethered dendrons for SE and AM implants.

Computer-assisted design and manufacture of implants in the late reconstruction of extensive orbital fractures

To evaluate the use of computer-assisted designed and manufactured (CAD/CAM) orbital wall and floor implants for late reconstruction of extensive orbital fractures.

Early loading at 21 days of non-submerged titanium implants with a chemically modified sandblasted and acid-etched surface: 3-year results of a prospective study in the posterior mandible

BACKGROUND: This study evaluates 3-year success rates of titanium screw-type implants with a chemically modified sandblasted and acid-etched surface (mod SLA), which were functionally loaded after 3 weeks of healing. METHODS: A total of 56 implants, inserted in the posterior mandibles of 39 partially edentulous patients, underwent undisturbed healing for 3 weeks. At day 21, the implants were fully loaded with provisional crowns. Definitive metal ceramic restorations were fabricated after 6 months of healing. Clinical measurements regarding soft tissue parameters and radiographs were obtained at different time points up to 36 months after implant placement. The soft tissue and radiographic parameters for the mod SLA implants after 3 years in function were compared to a historic control group of implants with an SLA surface using an early loading protocol after 6 weeks. RESULTS: None of the implants failed to integrate. However, two implants were considered "spinners" at day 21 and were left unloaded for an extended period. Therefore, 96.4% of the inserted implants were loaded according to the protocol tested. All 56 implants, including the "spinners," showed favorable clinical and radiographic findings at the 3-year follow-up examination. All 56 implants were considered successfully integrated, resulting in a 3-year survival and success rate of 100%. Dental implants with a mod SLA surface demonstrated statistically significant differences for probing depths and clinical attachment level values compared to the historic control group, with the mod SLA surface implants having overall lower probing depths and clinical attachment level scores. CONCLUSION: This prospective study using an early loading protocol demonstrates that titanium implants with the mod SLA surface can achieve and maintain successful tissue integration over a period of 3 years.

Complication and failure rates in patients treated for chronic periodontitis and restored with single crowns on teeth and/or implants

Objectives: To assess the biological and technical complication rates of single crowns on vital teeth (SC-V), endodontically treated teeth without post and core (SC-E), with a cast post and core (SC-PC) and on implants (SC-I). Material and methods: From 392 patients with chronic periodontitis treated and documented by graduate students during the period from 1978 to 2002, 199 were reexamined during 2005 for this retrospective cohort study, and 64 of these patients were treated with SCs. Statistical analysis included Kaplan–Meier survival functions and event rates per 100 years of object-time. Poisson regression was used to compare the four groups of crowns with respect to the incidence rate ratio of failures, and failures and complications combined over 10 years and the entire observation period. Results: Forty-one (64%) female and 23 (36%) male patients participated in the reexamination. At the time of seating the crowns, the mean patient age was 46.8 (range 24–66.3) years. One hundred and sixty-eight single unit crowns were incorporated. Their mean follow-up time was 11.8 (range 0.8–26.4) years. During the time of observation, 22 biological and 11 technical complications occurred; 19 SC were lost. The chance for SC-V (56) to remain free of any failure or complication was 89.3% (95% confidence interval [CI] 76.1–95.4) after 10 years, 85.8% (95% CI 66–94.5) for SC-E (34), 75.9% for SC-PC (39), (95% CI 58.8–86.7) and 66.2% (95% CI 45.1–80.7) for SC-I (39). Over 10 years, 95% of SC-I remained free of failure and demonstrated a cumulative incidence of failure or complication of 34%. Compared with SC-E, SC-I were 3.5 times more likely to yield failures or complications and SC-PC failed 1.7 times more frequently than did SC-E. SC-V had the lowest rate of failures or complications over the 10 years. Conclusions: While SCs on vital teeth have the best prognosis, those on endodontically treated teeth have a slightly poorer prognosis over 10 years. Crowns on teeth with post and cores and implant-supported SCs displayed the highest incidence of failures and complications.

Early loading after 21 days of healing of nonsubmerged titanium implants with a chemically modified sandblasted and acid-etched surface: two-year results of a prospective two-center study

PURPOSE: The aim of this two-center study was to evaluate screw-type titanium implants with a chemically modified, sandblasted and acid-etched surface when placed in the posterior maxilla or mandible, and loaded 21 days after placement. MATERIAL AND METHODS: All 56 patients met strict inclusion criteria and provided informed consent. Each patient displayed either a single-tooth gap, an extended edentulous space, or a distal extension situation in the posterior mandible or maxilla. Eighty-nine dental implants (SLActive, Institut Straumann AG, Basel, Switzerland) were inserted according to an established nonsubmerged protocol and underwent undisturbed healing for a period of 21 days. Where appropriate, the implants were loaded after 21 days of healing with provisional restorations in full occlusion. Definitive metal ceramic restorations were fabricated and positioned on each implant after 6 months of healing. Clinical measurements regarding soft tissue parameters and radiographs were obtained at different time points up to 24 months after implant placement. RESULTS: Of the 89 inserted implants, two (2.2%) implants failed to integrate and were removed during healing, and two (2.2%) additional implants required a prolonged healing time. A total of 85 (95.6%) implants were therefore loaded without incident after 21 days of healing. No additional implant was lost throughout the study period, whereas one implant was lost to follow-up and therefore left unaccounted for further analysis. The remaining 86 implants all exhibited favorable radiographic and clinical findings. Based on strict success criteria, these implants were considered successfully integrated 2 years after insertion, resulting in a 2-year success rate of 97.7%. CONCLUSION: The results of this prospective two-center study demonstrate that titanium implants with a modified SLA surface can predictably achieve successful tissue integration when loaded in full occlusion 21 days after placement. Integration could be maintained without incident for at least 2 years of follow-up.

A 10-year retrospective analysis of marginal bone-level changes around implants in periodontally healthy and periodontally compromised tobacco smokers

to compare the 10-year marginal bone loss rates around implants supporting single-unit crowns in tobacco smokers with and without a history of treated periodontitis.

A 10-year retrospective analysis of radiographic bone-level changes of implants supporting single-unit crowns in periodontally compromised vs. periodontally healthy patients

AIM: To compare the 10-year peri-implant bone loss (BL) rate in periodontally compromised (PCP) and periodontally healthy patients (PHP) around two different implant systems supporting single-unit crowns. MATERIALS AND METHODS: In this retrospective, controlled study, the mean BL (mBL) rate around dental implants placed in four groups of 20 non-smokers was evaluated after a follow-up of 10 years. Two groups of patients treated for periodontitis (PCP) and two groups of PHP were created. For each category (PCP and PHP), two different types of implant had been selected. The mBL was calculated by subtracting the radiographic bone levels at the time of crown cementation from the bone levels at the 10-year follow-up. RESULTS: The mean age, mean full-mouth plaque and full-mouth bleeding scores and implant location were similar between the four groups. Implant survival rates ranged between 85% and 95%, without statistically significant differences (P>0.05) between groups. For both implant systems, PCP showed statistically significantly higher mBL rates and number of sites with BL> or =3 mm compared with PHP (P<0.0001). CONCLUSIONS: After 10 years, implants in PCP yielded lower survival rates and higher mean marginal BL rates compared with those of implants placed in PHP. These results were independent of the implant system used or the healing modality applied.

Ten-year results of a three-arm prospective cohort study on implants in periodontally compromised patients. Part 1: implant loss and radiographic bone loss

OBJECTIVES: The aim of this study was to compare the long-term outcomes of implants placed in patients treated for periodontitis periodontally compromised patients (PCP) and in periodontally healthy patients (PHP) in relation to adhesion to supportive periodontal therapy (SPT). MATERIAL AND METHODS: One hundred and twelve partially edentulous patients were consecutively enrolled in private specialist practice and divided into three groups according to their initial periodontal condition: PHP, moderate PCP and severe PCP. Perio and implant treatment was carried out as needed. Solid screws (S), hollow screws (HS) and hollow cylinders (HC) were installed to support fixed prostheses, after successful completion of initial periodontal therapy (full-mouth plaque score <25% and full-mouth bleeding score <25%). At the end of treatment, patients were asked to follow an individualized SPT program. At 10 years, clinical measures and radiographic bone changes were recorded by two calibrated operators, blinded to the initial patient classification. RESULTS: Eleven patients were lost to follow-up. During the period of observation, 18 implants were removed because of biological complications. The implant survival rate was 96.6%, 92.8% and 90% for all implants and 98%, 94.2% and 90% for S-implants only, respectively, for PHP, moderate PCP and severe PCP. The mean bone loss was 0.75 (+/- 0.88) mm in PHP, 1.14 (+/- 1.11) mm in moderate PCP and 0.98 (+/- 1.22) mm in severe PCP, without any statistically significant difference. The percentage of sites, with bone loss > or =3 mm, was, respectively, 4.7% for PHP, 11.2% for moderate PCP and 15.1% for severe PCP, with a statistically significant difference between PHP and severe PCP (P<0.05). Lack of adhesion to SPT was correlated with a higher incidence of bone loss and implant loss. CONCLUSION: Patients with a history of periodontitis presented a lower survival rate and a statistically significantly higher number of sites with peri-implant bone loss. Furthermore, PCP, who did not completely adhere to the SPT, were found to present a higher implant failure rate. This underlines the value of the SPT in enhancing the long-term outcomes of implant therapy, particularly in subjects affected by periodontitis, in order to control reinfection and limit biological complications.

Osseoperception: active tactile sensibility of osseointegrated dental implants

The phenomenon of developing a certain tactile sensibility through osseointegrated dental implants is called osseoperception. Active tactile sensibility can be tested by having the subject bite on test bodies. The aim of the study was to describe the active tactile sensibility of single-tooth implants based on the 50% value and the slope of the sensibility curve at the 50% value.