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.

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.

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).

A 5-year prospective multicenter study of early loaded titanium implants with a sandblasted and acid-etched surface

For dental implants to be successful, osseointegration must occur, but it is unknown how much time must pass for osseointegration to be established. Preclinical studies suggested that titanium implants with a sandblasted and acid-etched (SLA) surface were more osteoconductive and allowed more rapid osseointegration than machined or turned implant surfaces. The hypothesis of this study was that implants with an SLA surface could be loaded in half the conventional healing time of machined-surface implants and that, after loading, the implants would be successful for 5 years.

10-Year Survival and Success Rates of 511 Titanium Implants with a Sandblasted and Acid-Etched Surface: A Retrospective Study in 303 Partially Edentulous Patients

Purpose: This retrospective study assessed the 10-year outcomes of titanium implants with a sandblasted and acid-etched (SLA) surface in a large cohort of partially edentulous patients. Materials and Methods: Records of patients treated with SLA implants between May 1997 and January 2001 were screened. Eligible patients were contacted and invited to undergo a clinical and radiologic examination. Each implant was classified according to strict success criteria. Results: Three hundred three patients with 511 SLA implants were available for the examination. The mean age of the patients at implant surgery was 48 years. Over the 10-year period, no implant fracture was noted, whereas six implants (1.2%) were lost. Two implants (0.4%) showed signs of suppuration at the 10-year examination, whereas seven implants had a history of peri-implantitis (1.4%) during the 10-year period, but presented with healthy peri-implant soft tissues at examination. The remaining 496 implants fulfilled the success criteria. The mean Plaque Index was 0.65 (±0.64), the mean Sulcus Bleeding Index 1.32 (±0.57), the mean Probing Depth 3.27 mm (±1.06), and the mean distance from the implant shoulder to the mucosal margin value -0.42 mm (±1.27). The radiologic mean distance from the implant shoulder to the first bone-to-implant contact was 3.32 mm (±0.73). Conclusion: The present retrospective analysis resulted in a 10-year implant survival rate of 98.8% and a success rate of 97.0%. In addition, the prevalence of peri-implantitis in this large cohort of orally healthy patients was low with 1.8% during the 10-year period.

Immediate restoration of nonsubmerged titanium implants with a sandblasted and acid-etched surface: five-year results of a prospective case series study using clinical and radiographic data

The aim of this study was to evaluate the survival and success rates of immediately restored implants with sandblasted, large-grit, acid-etched (SLA) surfaces over a period of 5 years. Twenty patients (mean age, 47.3 years) received a total of 21 SLA wide-neck implants in healed mandibular first molar sites after initial periodontal treatment. To be included in the study, the implants had to demonstrate primary stability with an insertion torque value of 35 Ncm. A provisional restoration was fabricated chairside and placed on the day of surgery. Definitive cemented restorations were inserted 8 weeks after surgery. Community Periodontal Index of Treatment Needs (CPITN) indices and the radiographic distance between the implant shoulder and the first visible bone-implant contact (DIB) were measured and compared over the study period. The initial mean CPITN was 3.24, and decreased over the study period to 1.43. At the postoperative radiographic examination, the mean DIB was 1.41 mm for the 21 implants, indicating that part of the machined neck of the implants was placed slightly below the osseous crest. The mean DIB value increased to 1.99 mm at the 5-year examination. This increase proved to be statistically significant (P < .0001). Between the baseline and 5-year examinations, the mean bone crest level loss was 0.58 mm. Success and survival rates of the 21 implants after 5 years of function were 100%. This 5-year study confirms that immediate restoration of mandibular molar wide-neck implants with good primary stability, as noted by insertion torque values of at least 35 Ncm, is a safe and predictable procedure.

Enhanced bone apposition around biofunctionalized sandblasted and acid-etched titanium implant surfaces. A histomorphometric study in miniature pigs

Microrough titanium (Ti) surfaces of dental implants have demonstrated more rapid and greater bone apposition when compared with machined Ti surfaces. However, further enhancement of osteoblastic activity and bone apposition by bio-functionalizing the implant surface with a monomolecular adsorbed layer of a co-polymer - i.e., poly(L-lysine)-graft-poly(ethylene glycol) (PLL-g-PEG) and its derivatives (PLL-g-PEG/PEG-peptide) - has never been investigated. The aim of the present study was to examine early bone apposition to a modified sandblasted and acid-etched (SLA) surface coated with an Arg-Gly-Asp (RGD)-peptide-modified polymer (PLL-g-PEG/PEG-RGD) in the maxillae of miniature pigs, and to compare it with the standard SLA surface. Test and control implants had the same microrough topography (SLA), but differed in their surface chemistry (polymer coatings). The following surfaces were examined histomorphometrically: (i) control - SLA without coating; (ii) (PLL-g-PEG); (iii) (PLL-g-PEG/PEG-RDG) (RDG, Arg-Asp-Gly); and (iv) (PLL-g-PEG/PEG-RGD). At 2 weeks, RGD-coated implants demonstrated significantly higher percentages of bone-to-implant contact as compared with controls (61.68% vs. 43.62%; P < 0.001). It can be concluded that the (PLL-g-PEG/PEG-RGD) coatings may promote enhanced bone apposition during the early stages of bone regeneration.

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.

Clinical performance of wide-body implants with a sandblasted and acid-etched (SLA) surface: results of a 3-year follow-up study in a referral clinic

PURPOSE: The aim of this study was to evaluate the 3-year success rates of wide-body implants with a regular- or wide-neck configuration and a sandblasted, large grit, acid-etched (SLA) surface. MATERIALS AND METHODS: A total of 151 implants were consecutively placed in posterior sites of 116 partially edentulous patients in a referral clinic at the School of Dental Medicine, University of Bern. All implants were restored with cemented crowns or fixed partial dentures after a healing period of 6 to 8 weeks (for implants placed without simultaneous bone augmentation) or 10 to 14 weeks (for implants with simultaneous bone augmentation). All patients were recalled 36 months following implant placement for a clinical and radiographic examination. RESULTS: One implant failed to integrate during healing, and 11 implants were lost to follow-up and considered dropouts. The remaining 139 implants showed favorable clinical and radiographic findings and were considered successfully integrated at the 3-year examination. This resulted in a 3-year success rate of 99.3%. Radiographic evaluation of 134 implants indicated stability of the crestal bone levels: During the study period, the crestal bone level changed less than 0.5 mm for 129 implants. CONCLUSION: Successful tissue integration was achieved with wide-body implants with a regular or a wide-neck configuration and an SLA surface with high predictability. This successful tissue integration was well maintained for up to 3 years of follow-up.

Clinical field trial examining an implant with a sand-blasted, acid-etched surface

BACKGROUND: Conventionally, endosseous dental implants have required 3 to 6 months of uninterrupted healing based on observations for dental implants that were characterized by a relatively smooth machined surface. Many studies have since demonstrated that implants with a roughened surface resulted in greater bone apposition, earlier bone contact, and a stronger bond between the implant and the bone, suggesting that implants with roughened surfaces could be loaded earlier than 3 to 6 months. Formal clinical studies confirmed that implants with rough surfaces can have abutments placed and be loaded occlusally as early as 6 weeks postplacement. The purpose of this prospective, human clinical investigation was to evaluate a large number of implants with a specific rough surface (sand-blasted acid-etched [SLA]) placed in everyday practice under routine private-practice conditions. METHODS: A prospective, multicenter, human clinical observational study was initiated with the goal of recruiting a minimum of 500 patients and 800 implants. The implants were to be placed and restored in predominantly private-practice settings around the world. Ninety-two practitioners in 16 countries agreed to participate, and 86 followed the study design. Patients had to be in good health, have sufficient bone to encase the implant, and agree to return for recall appointments. Exclusion criteria included heavy smoking (>10 cigarettes a day) and bone augmentation procedures at the implant site. All implants were two-piece (an abutment was to be placed after 6 weeks of healing) and were characterized by the presence of a transmucosal polished collar. Each implant had an SLA surface. All implants were positioned using a non-submerged (single-stage) surgical technique. Survival and success rates were calculated by life-table analyses. RESULTS: A total of 706 patients were enrolled and 1,406 implants were placed. In the final analyses, 590 patients with 990 implants (70.4% of those enrolled) met all inclusion criteria, including placement of an abutment and provisional restoration within 63 days of surgical placement. The majority of implants were 10 and 12 mm long (78.7%) and were placed in type II and III bone (87%). Seventy-three percent of the implants were placed in the mandible, and 27% were placed in the maxilla. The cumulative survival rate was 99.56% at 3 years and 99.26% at 5 years. The overall success rate was 99.12% at 3 years and 97.38% after 5 years. CONCLUSIONS: Under private-practice conditions, implants with an SLA surface could be placed and restored predictably within 6 to 8 weeks. Data from this prospective, multicenter, human observational study reinforced the results of more formal clinical studies and demonstrated that implants with the SLA surface can be restored in patients in approximately half of the time of conventional healing periods.

Bone apposition around two different sandblasted and acid-etched titanium implant surfaces: a histomorphometric study in canine mandibles

PURPOSE: The aim of this study was to evaluate bone apposition to a modified sandblasted and acid-etched (SLA) implant surface (modSLA) in the canine mandible as compared with the standard SLA surface. MATERIAL AND METHODS: In this experimental study, all mandibular premolars and first molars were extracted bilaterally in five foxhounds. After a healing period of 6 months, each side of the mandible received six randomly assigned dental implants alternating between the standard SLA and modSLA surface. The dogs were sacrificed at 2 weeks (n=2) or 4 weeks (n=3) after implant placement. Histologic and histomorphometric analyses were then performed for each implant. RESULTS: The microscopic healing patterns at weeks 2 and 4 for the two implant types with the standard SLA and modSLA surfaces showed similar qualitative findings. New bone tissue had already established direct contact with implant surfaces after 2 weeks of healing. The mean percentage of newly formed bone in contact with the implant (BIC) was significantly greater for modSLA (28.2+/-7.9%) than for SLA (22.2+/-7.3%) (P<0.05). This difference was no longer evident after 4 weeks. An increase in BIC for both implant surface types occurred from weeks 2 to 4. This increase was statistically significant when compared with SLA at 2 weeks (P<0.05), but not when compared with modSLA at 2 weeks. CONCLUSION: The data from the present study demonstrate significantly more bone apposition for the modSLA surface than the standard SLA surface after 2 weeks of healing. This increased bone apposition may allow a further reduction of the healing period following implant placement for patients undergoing early loading procedures.

Early loading of sandblasted and acid-etched implants: a randomized-controlled double-blind split-mouth study. Five-year results

OBJECTIVES: The aim of the present split-mouth study is to assess the peri-implant conditions around early-loaded sandblasted and acid-etched (SLA) implants, 5 years after abutment connection and to compare, in the same patients, the results obtained with a standard protocol using identical implants with a TPS surface. MATERIAL AND METHODS: Surgical procedure was performed by the same operator and was identical at test (SLA) and control (TPS) sites, in 32 healthy patients. Abutment connection was carried out at 35 N cm 6 weeks postsurgery for test sites and 12 weeks for the controls. Patients were seen regularly, for control and professional cleaning. At 60 months, clinical measures and radiographic bone changes were recorded by the same operator, blind to the type of surface of the implant, on 27 patients, as five patients were lost to follow-up. RESULTS: A total number of 106 implants were examined. No implant was lost. No significant differences were found with respect to the presence of plaque [modified plaque index (mPI) 0.27+/-0.56 vs. 0.32+/-0.54], bleeding on probing (29% vs. 32%), mean pocket depth (3.2+/-1 vs. 3.2+/-1 mm) or mean marginal bone loss (0.32+/-1.04 vs. 0.44+/-1.12 mm) between test and control. Four implants that presented 'spinning' at the time of abutment connection presented no significant differences from the rest of the test sites. CONCLUSION: The results of this prospective study confirm that SLA implants, under defined conditions, are suitable for early loading at 6 weeks in both the mandible and the maxilla. Limited implant spinning, occasionally found at abutment connection, produces no detrimental effect on the clinical outcome when properly handled.

Early loading of nonsubmerged titanium implants with a chemically modified sand-blasted and acid-etched surface: 6-month results of a prospective case series study in the posterior mandible focusing on peri-implant crestal bone changes and implant stability quotient (ISQ) values

PURPOSE: The aim of this prospective case series study was to evaluate the short-term success rates of titanium screw-type implants with a chemically modified sand-blasted and acid-etched (mod SLA) surface after 3 weeks of healing. MATERIAL AND METHODS: A total of 56 implants were inserted in the posterior mandible of 40 partially edentulous patients exhibiting bone densities of class I to III. After a healing period of 3 weeks, all implants were functionally loaded with a screw-retained crown or fixed dental prosthesis. The patients were recalled at weeks 4, 7, 12, and 26 for monitoring and assessment of clinical and radiological parameters, including implant stability quotient (ISQ) measurements. RESULTS: None of the implants failed to integrate. However, two implants were considered "spinners" at day 21 and 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 6-month follow-up examination. The ISQ values increased steadily throughout the follow-up period. At the time of implant placement, the range of ISQ values exhibited a mean of 74.33, and by week 26, a mean value of 83.82 was recorded. Based on strict criteria, all 56 implants were considered successfully integrated, resulting in a 6-month survival and success rate of 100.0%. CONCLUSION: This prospective study using an early-loading protocol after 3 weeks of healing demonstrated that titanium implants with the modified SLA surface can achieve and maintain successful tissue integration over a period of at least 6 months. The ISQ method seems feasible to monitor implant stability during the initial wound-healing period.

Dentin Bond Strength of Two Recent CAD/CAM-Materials after Storage

Purpose: To investigate the bond strength to dentin of two recent resin-ceramic materials for computer-aided design/computer-aided manufacturing (CAD/CAM) after 24 hours and after six months storage. Methods and Materials: Ninety cylinders were milled out of Lava Ultimate (3M ESPE) and 90 cylinders out of VITA ENAMIC (VITA Zahnfabrik) (dimension of cylinders: ∅=3.6 mm, h=2 mm). All Lava Ultimate cylinders were sandblasted (aluminium oxide, grain size: 27 μm) and cleaned with ethanol, whereas all VITA ENAMIC cylinders were acid-etched (5% hydrofluoric acid) and cleaned with water-spray. According to the three groups of cements used, the cylinders (n=30/resin-ceramic material) were further pretreated with 1) Scotchbond Universal for RelyX Ultimate (3M ESPE), 2) CLEARFIL Ceramic Primer for PANAVIA F2.0 (Kuraray), or 3) no further pretreatment for Ketac Cem Plus (3M ESPE). The cylinders were then bonded to ground human dentin specimens with 1) Scotchbond Universal and RelyX Ultimate (light-cured), 2) ED PRIMER II and PANAVIA F2.0 (light-cured), or 3) no adhesive system; Ketac Cem Plus (self-cured). Shear bond strength (SBS) was measured after 24 hours for 15 specimens/group and after six months (37°C, 100% humidity) for the other 15 specimens/group. SBS-values were statistically analysed with nonparametric ANOVA followed by exact Wilcoxon rank sum tests (α=0.05). Results: SBS of the two resin-ceramic materials and the three cements after 24 hours and after six months storage are shown in Figure 1. The statistical analysis showed that the duration of storage had a significant effect on SBS of Lava Ultimate for all three cements but had no significant effect on SBS of VITA ENAMIC. For Lava Ultimate SBS-values were (MPa; medians after 24 hours/six months): 13.5/22.5 (p=0.04) for RelyX Ultimate, 11.4/5.8 (p=0.0006) for PANAVIA F2.0, and 0.34/0.09 (p=0.04) for Ketac Cem Plus (Fig. 1). For VITA ENAMIC SBS-values were (MPa; medians after 24 hours/six months): 16.0/21.2 (p=0.10) for RelyX Ultimate, 11.4/14.4 (p=0.06) for PANAVIA F2.0, and 0.43/0.41 (p=0.32) for Ketac Cem Plus (Fig. 1). After 24 hours, there was no significant difference in SBS between Lava Ultimate and VITA ENAMIC for all three cements (p≥0.37). After six months, there was no significant difference in SBS between Lava Ultimate and VITA ENAMIC for RelyX Ultimate and Ketac Cem Plus (p≥0.07) whereas for PANAVIA F2.0, SBS was significantly lower for Lava Ultimate than for VITA ENAMIC (p<0.0001). Conclusion: SBS of Lava Ultimate was more affected by six months storage and by the cement used than was VITA ENAMIC.

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.