A comparison of hydroxylapatite coated implant retained fixed and removable mandibular prostheses over 4 to 6 years

In a 6-year prospective clinical study, 181 hydroxylapatite coated endosseous dental implants were placed into the anterior mandible of 48 patients. Twenty-one patients were treated with fixed prostheses and 27 patients with an overdenture. When the implants were exposed all 181 had integrated. To date, there is 100% survival of all implants and they all retain a functioning prostheses. The initial results were very promising, in both groups the interval success was over 95% in the first 4 years of the study. However, by year 6, the interval success rates had fallen to 83% for both the fixed and removable groups. This study also compares the construction and maintenance complications for the two types of restorations. The clinical time taken, after implant exposure, to construct the prostheses was similar whether the fixed (mean of 8 visits) or removable option (mean of 7 visits) was chosen. However, the removable restoration cost less than half the price of the fixed when both technical time and implant component costs were evaluated. Maintenance for both groups was higher than expected, but patients required more appointments in the removable group both in the first year and beyond. Regarding the prostheses itself, the incidence of remakes, relines and general adjustments was higher in the removable group. This study has shown that the overdenture offers an effective and initially a more economical alternative to the fixed prostheses, in the treatment of the edentulous mandible. However, long-term maintenance of such a prosthesis can be significant.     

Early loading of implants with fixed dental prostheses in edentulous mandibles: 4.5‐year clinical results from a prospective study

Aim: The purpose of this study was to evaluate the survival and success of early‐loaded implants placed in the intraforaminal area of the edentulous mandible, and the survival of the implant‐supported fixed dental prostheses (FDP). Material and methods: Thirty‐seven patients (18.9% male, mean age 64.5 years) with edentulous lower jaws were treated with implant‐supported FDPs in the mandible. One hundred and eighty‐five screw‐type implants were placed in the intraforaminal area of the symphysis (five implants per patient). Immediately after implant placement, a framework was fabricated and the FDP was manufactured on the framework. Within 2 weeks, the implants were rigidly connected and loaded with the implant‐retained FDP. Results: During the 1–8‐year observation period (mean 4.5 years), a total of 32 implant‐retained complications occurred. Nineteen implants were lost in 10 patients, resulting in a cumulative survival of 89.7%. Nine implants in five patients did not osseointegrate. Although these implants were not removed, because stability within the connective tissue was acceptable and inflammation was absent, they were recorded as unsuccessful. Consequently, the cumulative success declined to 84.9%. Four implants in three patients had clinical signs of periimplantitis (2.2% of all implants). Denture‐related complications included one complete failure, when one FDP had to be removed after the last of five implants had been replaced. Furthermore, 10 fractures of the framework occurred in six patients, three FDPs had to be adapted or modified, and the facing of the FDP had to be repaired 16 times in 11 patients. Conclusion: Although one‐stage early‐loaded implants functioned well for most patients with edentulous mandibles, immediate loading is associated with a larger number of implant‐related complications than in other studies investigating delayed loading. Because of the substantial prosthetic complications and aftercare, this procedure cannot be generally recommended. To cite this article:
Schwarz S, Gabbert O, Hassel A J, Schmitter M, Séché C, Rammelsberg P. Early loading of implants with fixed dental prostheses in edentulous mandibles: 4.5‐year clinical results from a prospective study.
Clin. Oral Impl. Res. 21 , 2010; 284–289.
doi: 10.1111/j.1600‐0501.2009.01843.x     

Early loading of mandibular full-arch bridges screw retained after 1 week to four to five Monotype implants: 3-year results from a prospective multicentre study

Objectives: This prospective multicentre study provides clinical experience up to 3 years to support a simplified treatment for mandibular edentulism within 1 week by using one‐stage implant surgery and a screw‐retained full‐arch bridge. Methods: Two hundred and fifty ITI Monotype^® implants were installed in 62 patients out of 66 patients; 60 patients got four implants each and two got five implants. After 1 week, a final bridge was in function. Radiographs were taken as baseline for vertical bone loss up to 3 years post‐loading for the whole cluster and specific effects of gender, centre, age, bone class, implant length over time were compiled. Clinical (mPI, SBI) and subjective parameters such as general oral hygiene and patient satisfaction were recorded and repeated at specified intervals up to 3 years. Results: Four patients were excluded at surgery and are not involved in the follow‐ups. At 1 year, 61 patients (244 implants) were evaluable and all bridges were in function. After 3 years, 49 patients (194 implants) came to control. Eight patients died during the follow‐up period. Three patients lost one implant each. The cumulative implant survival rate was 98.55% and the success rate for the prosthesis was 100%. As calculated from measurable radiographs, the mean bone level at baseline was 1.63±0.78 and at 1 and 3 years 2.50±0.60 and 2.56±0.74, respectively. Using the mixed model analysis and Friedman test, the time in situ, centre and bone class had significant effect on the bone resorption and to some small extent even, the implant length. Gender and age were unaffected. Oral hygiene and patient satisfaction of the treatment were improved. Conclusions: The results indicate that one‐part self‐tapping sandblasted, large‐grit, acid‐etched (SLA) implants are suitable for loading within 1 week. In the whole period, the mean bone crestal resorption was <1 mm, which is in agreement with other similar studies.     

A 4-year prospective clinical and radiological study of maxillary dental implants supporting single-tooth crowns using early and delayed loading protocols

Background: Recent studies have showed that immediate/early loading of dental implants is a clinically feasible concept with results similar to those for standard two‐stage procedures, especially in the mandible. However, there are only a few studies regarding the immediate/early loading of maxillary implants supporting single‐tooth crowns. Purpose: The aim of this study was to compare the clinical and radiological outcomes of early‐ and delayed‐loaded dental implants supporting single‐tooth crowns in the maxilla. Materials and Methods: Twenty‐nine patients were consecutively treated between 2000 and 2002 with 59 Brånemark System MK III TiUnite implants (Nobel Biocare AB, Göteborg, Sweden) in the maxilla. Two groups were formed according to the loading protocols. In the test group, definitive implant‐supported single crowns were delivered to 19 patients 6 weeks after the implant placement. In the control group, definitive implant‐supported single crowns were delivered to 10 patients 6 months after the implant placement. Clinical and radiographic parameters were recorded at baseline, 1 to 4 years. Implant stability measurements have only been performed at 4‐year follow‐up recall. Results: Overall, three implants were lost during the study period. Two implants were lost in the test group including 36 implants, which indicated a survival rate of 94.4%. One of the lost implants was replaced and then osseointegrated successfully. One implant was lost in the control group during the healing period, which indicated a survival rate of 95.7%. The average marginal bone loss was 1.11 mm for 56 implants after 4 years. There were no significant differences in marginal bone levels, insertion torque, and resonance frequency values between the two groups. Conclusion: The results of this study indicate that 6 weeks of early loading period for TiUnite‐surface titanium implants in the maxilla is reliable and predictable for this patient population and may offer an alternative to the standard loading protocol.     

Five-year results from a randomized, controlled trial on early and delayed loading of implants supporting full-arch prosthesis in the edentulous maxilla

Objectives: The overall aim was to compare the clinical outcomes of early and delayed implant loading in the totally edentulous maxilla during 5 years of function. Materials and methods: Twenty‐four patients with edentulous maxillae were randomized in two groups and subjected to early (test, n=16) or delayed (control, n=8) loading. A total of 142 implants were placed and 139 implants (Straumann AG) were loaded with full‐arch bridges and followed for 5 years. Results: All patients received and maintained a fixed bridge throughout the study period. Five (5.3%) test implants in three patients and two (4.3%) control implants in two patients were lost during the 5 years (NS). There were no differences in implant stability as measured with resonance frequency analysis at 5 years. More bone loss occurred at test than at control implants, ?0.8 mm (SD 1.2) vs. ?0.3 mm (SD 1.1), respectively. However, test implants showed a more coronal marginal bone level than control implants after 5 years, 2.9 mm (SD 1.1) vs. 3.7 mm (SD 1.2) from the implant shoulder, respectively. No control implants and four (4.4%) test implants in three (18.8%) patients showed >3 mm bone loss after 5 years. Two of the latter implants in one patient also showed increased probing depths, bleeding at probing and plaque accumulation. Tooth fracture was the most common prosthetic complication. The use of lingual gold onlay effectively reduced the number of resin‐related complications as opposed to a resilient mouth guard. Conclusions: The present randomized controlled trial showed no important differences between early and delayed loading of implants in the edentulous maxilla after 5 years of function. A favourable long‐term marginal bone response to the sandblasted large‐grit acid‐etched (SLA) surface was observed. Technical complications were mainly resin‐related which could be avoided by the use of a lingual gold onlay. It is concluded that early loading of SLA‐surface implants for support of full‐arch bridges represents a viable therapy for the totally edentulous maxilla.     

Immediate loading in the completely edentulous mandible: technical procedure and clinical results up to 3 years of functional loading

Objectives: This prospective mono‐center study describes a clinical technique to provide dental implants with a temporary cross‐arch cantilever bridge functionally loaded on the day of fixture insertion and discusses the 3‐year follow‐up of four to six machined surface Brånemark implants installed in the interforamina area. Material and methods: Ninety Brånemark implants were installed in 18 edentulous mandibles. Five patients were heavy smokers and one had Down syndrome. The day of surgery, a 10 unit provisional glassfiber‐reinforced cantilever bridge was installed. The final 12 unit bridge was in place after an average of 144 days (range 10–332). Bone‐to‐implant level was assessed radiologically from the day of surgery up to 3 years. Results: Two out of five fixtures were lost within 3 months in the Down syndrome patient but the provisional bridge continued to function on the three remaining implants until the patient was successfully reoperated. Another implant was lost after 11 months due to a non‐detected fracture in the metal framework, resulting in overloading of the cantilever part. As no additional losses occurred during the follow‐up time (range 57–26 months), the total failure rate is 3/91 (3.3%). Seventeen of the 18 patients are loading their implants more than 3 years and nine have moved beyond the 4‐year period. Average bone remodelling as measured on the apical radiographs from 12 patients at 0, 12 and 36 months revealed a statistically significant bone loss from the initial 0.1 mm [standard deviation (SD) 0.2; range 0–0.7] toward 1.8 mm (SD 0.2; range 1.6–2.2) during the first year of function. (Wilcoxon's signed rank test; P<0.002). After 3 years, no further significant bone loss occurred. Conclusion: This 3‐year study shows that machined surface Brånemark implants can be immediately loaded with cross‐arch cantilever bridges with an average bone‐remodelling pattern indicative of a steady state after 1 year of loading.     

Clinical outcomes of immediate/early loading of dental implants. A literature review of recent controlled prospective clinical studies

Two previous reviews have evaluated the clinical outcomes of immediate/early loading of dental implants based on studies published until 2005. ^1,2 The aim of the present paper was to review controlled clinical studies on the subject published since 2005 including at least 10 patients in each group followed for at least one year in function. Six comparative studies were found and none of these showed any differences in survival rates or marginal bone loss after one to five years. Most authors used specified inclusion criteria to avoid known risk factors such as soft bone, short implants and bruxism. Data from one randomized study in the edentulous maxilla showed no differences between early and delayed loading in consecutive clinical routine cases including short implants and soft bone. Three additional studies comparing different surfaces or implant designs under immediate loading were reviewed. No differences between implants with a moderately rough or smooth surface topography were observed. The data add to the previous bulk of evidence that various designs of implants can be loaded shortly after their placement in both the mandible and the maxilla. However, one study reported on marginal bone loss around a novel one-piece implant design leading to implant failure which was not seen for control two-piece implants. ³     

Early loading of unsplinted implants supporting mandibular overdentures using a one-stage operative procedure with two different implant systems: a 2-year report

Background: Step‐wise reduction in loading protocols is necessary to evaluate early loading of implants with mandibular overdentures. Purpose: To compare the success rates of two different dental implant systems following conventional or early loading protocols in patients being rehabilitated with mandibular overdentures. Materials and Methods: Forty‐eight edentulous participants were randomly allocated to two different implant systems: one with a machined titanium implant surface (Sterioss, Nobel Biocare, Yorba Linda, California, USA) and the other with a roughened titanium surface (Southern Implants, Irene, South Africa). For each system, the participants were further divided into control groups, in whom mandibular implant overdentures and their respective matrices were inserted following a standard 12‐week healing period, and test groups, in whom a 6‐week healing period was followed prior to identical loading. Two unsplinted implants to support implant overdentures were placed in the anterior mandible of all participants, using a standardized one‐stage surgical procedure. Mobility tests and marginal bone levels, as well as periimplant parameters, were evaluated at each baseline and 52 and 104 weeks after surgery. Results: There was no statistically significant difference in the success rates of the two systems in either control or test groups. At the 2‐year evaluation, a success rate was found of 87.5% and 70.8.% for the control and test Sterioss groups, respectively, and 83.3% and 100% for the control and test Southern Implants groups were observed. For the Sterioss groups, eight implants were lost at an early stage: seven in the test group and one in the control group. For the Southern Implants control and test groups, no failures were seen at any time interval. There were no significant differences in marginal bone loss, Periotest values, and peri‐implant parameters between implant systems or between any of the control or test groups. Conclusions: Early loading, with step‐wise reductions in loading protocols, of unsplinted machined Sterioss and roughened Southern Implants fixtures with mandibular overdentures is possible for up to 2 years.     

Provisional implants: a clinical prospective study in 45 patients, from implant placement to delivery of the final bridge

Background: Protocols for submerged healing of dental implants often require the patient to have no teeth until suture removal and to wear a removable prosthesis during the remaining healing period. This may be inconvenient for the patient, and healing may be influenced negatively by the removable prosthesis. Purpose: The aim of the present prospective clinical study was to evaluate the use of provisional implants (PIS) to provide patients with a provisional fixed bridge during the healing of permanent implants. Materials and Methods: Twenty female and 25 male patients were consecutively included in the study. The 45 patients were treated for either partial (16 patients) or total (29 patients) edentulism in the maxilla. The permanent implants were placed first; as many PIS as possible were then installed between the permanent implants. After suturing, impressions from which to manufacture provisional bridges (to be cemented to the PIS) were taken. The patients were monitored with clinical and radiographic follow‐up from implant placement to delivery of the final prosthesis. Results: Five (2.2%) of the 230 permanent Brånemark System® implants (Nobel Biocare AB, Gothenburg, Sweden) did not integrate. None of the failures could be related to the presence of PIS between the permanent implants. Seven PIS failed during the observation period. In addition, 17 (9%) of the 192 PIS showed mobility at the second‐stage surgery although they had supported the provisional bridges without clinical symptoms. Forty‐four of 45 patients showed stabile PI bridges at the time of second‐stage surgery. Conclusion: Based on our experiences we concluded that provisional implants can be successfully used to provide patients with a fixed provisional bridge during the healing of permanent implants.     

Five-year prospective study of immediate/early loading of fixed prostheses in completely edentulous jaws with a bone quality-based implant system

Background: The concept of immediate loading of root‐form implants for fixed restorations has received increasing interest over the last 5 years. Several authors have commented on parameters that may influence results, including implant number, implant length, bone density, and patient habits. The trigger for bone remodeling around an implant may occur from the surgical trauma of insertion or the mechanical environment of strain at the interface. In the classic two‐stage approach, these were divided episodes, separated by 3 to 6 months. Immediate loading compresses this time frame; the two driving mechanisms for bone repair occur concurrently. A scientific approach to the interface development is to match the bone healing response of trauma (woven bone of repair) to the response of mechanical load (reactive woven bone), so the sum of these two entities does not result in fibrous tissue formation and clinical mobility of the implant. Purpose: It is the purpose of this article to review the scientific rationale of these statements and coordinate them to bone physiology and bone biomechanics. Materials and Methods: Findings from previous reports in the literature were reviewed and summarized to form the basis of a prospective study using a bone quality‐based implant system (Biohorizons, Maestro Dental Implants, Birmingham, AL, USA). A transitional prosthesis was delivered either on the day of surgery or within 2 weeks for 30 patients and 31 arches. A total of 244 implants were used to support these restorations, for an average of 7.8 implants per prosthesis. After 4 to 7 months, the final restorations were fabricated. One year after the final restoration was loaded, the implant survival was 100%; the 31 restorations also had a survival of 100% over this time frame. This report presents these implants and restorations over a 1‐ to 5‐year period, with an average follow‐up period of 2.6 years. Results: The bone loss from implant insertion to final prosthesis delivery averaged 0.7 mm. The first‐year bone loss after final prosthesis delivery averaged 0.07 mm. A slight increase in bone height was observed after the first year, but generally no increase was observed over the remaining evaluation period. Conclusions: In the current report, no implant failure occurred, and crestal bone loss values were similar to or less than values reported with the conditional two‐stage approach. This may be related to the number and position of implants, implant design, and/or the surface condition of the implant loading.     

Survival of NobelDirect implants: an analysis of 550 consecutively placed implants at 18 different clinical centers

Background: A recently introduced implant, the NobelDirect (Nobel Biocare AB, Göteborg, Sweden), has previously been documented with substantial bone resorption in a large number of operated cases. PurposeL The aim of this study was to evaluate the failure rate of NobelDirect implants in a retrospective multicenter survey. Materials and Methods: A total of 550 NobelDirect implants consecutively placed in over 269 patients at 18 centers were evaluated with regard to failure rate after an average follow‐up of about 1 year. Results: The overall failure percentage was 10.9% (59 failures). The 58 implants not loaded directly showed only one failure (1.7%) versus 58 failures (11.8%) of those implants that were loaded directly. A chemical x‐ray photoelectron spectroscopy analysis of an implant from the original batch showed up to 3.5% silicon at parts of the implants. A retrieval analysis of one implant removed at 2 years after placement demonstrated bone resorption down to the level of the fifth thread. Conclusions: It is concluded that the NobelDirect implant, if placed with a punch procedure, ground down in situ, and loaded directly, shows an unusually high failure rate at 1 year.     

Short-term clinical results of Nobel Direct implants: a retrospective multicentre analysis

PURPOSE: The present retrospective clinical study was undertaken to evaluate the survival rate and marginal bone conditions around Nobel Direct one-piece implants. The purpose was also to compare the results with when these implants are used for immediate/early loading with implants allowed to heal before loading. MATERIAL AND METHODS: Forty-three consecutive patients previously treated with 117 Nobel Direct implants at four different centres were evaluated. The implants had been used in both jaws for treatment after loss of single and multiple teeth. Immediate/early loading (within 2 weeks) with a provisional crown/bridge was applied to 95 implants, while 22 implants healed unloaded for 6 weeks to 6 months before loading. Calculations of marginal bone loss were performed in radiographs taken at placement and after an average of 10.2 months (range 1-18 months) of loading. RESULTS: Six (5.1%) of the 117 implants were removed during the follow up. All failed implants belonged to the immediate/early loading group giving a failure rate of 6.3% for this group and 0% for two-stage implants. The failure rate was higher for flapless (7.9%) than for flap surgery (0%). The marginal bone loss was -2.4 mm (SD 1.5) for all implants, while 37.6% showed more than 3 mm of loss during the follow up. Bone loss increased with time of follow up. Implants subjected to immediate/early loading showed more bone loss than two-stage implants: -2.6 mm (SD 1.5) vs. -1.6 mm (SD 1.1). Moreover, 41.3% of immediately loaded and 22.7% of two-stage implants presented with more than 3 mm of bone loss. CONCLUSIONS: This short-term retrospective analysis showed a poor clinical outcome of Nobel Direct implants. Extensive marginal bone loss (>3 mm) was found around more than 1/3 of the implants evaluated. Less resorption and no failures were experienced when implants were allowed to heal from 6 weeks to 6 months before occlusal loading. Within the limitations of the present study design, data indicate that immediate loading, the use of this implant for multi-unit constructions and flapless surgery are risk factors for failure of Nobel Direct implants.