Conventional and early loading of unsplinted ITI implants supporting mandibular overdentures

Three-Dimensional Evaluation of Alveolar Bone Levels Around Dental Implants and Natural Teeth: A Prospective Study

INTRODUCTION

Dental implants' efficacy is influenced by the quality and quantity of the osseous tissue present at the site designated for dental implants. Therefore, this study was conducted with the primary objective of assessing marginal bone loss around mandibular posterior dental implants at six and 18 months after prosthesis placement, compared with the contralateral natural tooth. The secondary objective was to determine the correlation between various factors such as periodontal status, age, gender, duration between first and second-stage surgery, and marginal bone loss.

MATERIALS AND METHODS

This prospective, split-mouth study was conducted on 24 patients, consisting of two groups: group 1, with single tooth replacement by a dental implant in the posterior mandible, and group 2, a contralateral natural tooth. The bleeding index (BI), probing depth (PD), and marginal bone loss were evaluated using cone-beam computed tomography at six and 18 months follow-up period after prosthesis placement.

RESULTS

Significant bone loss was observed in both groups across all regions (p < 0.05). The mean marginal bone loss was greater at 18 months in group 1 than at six months of follow-up, whereas in group 2, it was not significant. The total mean marginal bone loss during the follow-up period of 18 months was 0.05 mm on the buccal and lingual side, whereas it was 0.5 mm on the mesial side and 2 mm on the distal side. Similarly, in the control group, the total mean marginal bone loss was 0.03 mm on the buccal and lingual sides, whereas it was 0.04 mm on the mesial and distal sides. The PD and duration of second-stage surgery were significant predictors and showed a significant correlation with marginal bone loss.

CONCLUSION

PD and marginal bone loss were significantly higher in the implant group than in the natural tooth group over the follow-up period of 18 months, particularly on the distal side.

Clinical efficacy of early and delayed loading implants: A systematic review and meta-analysis

STATEMENT OF PROBLEM

Whether early loaded implants have similar clinical outcomes to delayed loaded implants is unclear.

PURPOSE

The purpose of this systematic review and meta-analysis was to compare the outcomes of early and delayed loading dental implants.

MATERIAL AND METHODS

Comprehensive searches of the MEDLINE, EMBASE, and Ovid databases were enriched by hand searches. Only human randomized controlled trials (RCTs) that compared the clinical efficacy of early and delayed loading were included. The survival rates and marginal bone level (MBL) changes were pooled and analyzed by risk ratios (RRs) and weighted mean differences (WMDs), respectively. The subgroup analyses, which were based on the Mantel-Haenszel and inverse-variance methods, included the types of prosthesis, implant time, occlusion, number of missing teeth, operation methods, dental position, healing methods, and type of first restoration. A funnel plot was used for heterogeneity analysis.

RESULTS

Eighteen trials were included from the initial 601 articles. The dental implant survival rates for the early and delayed loading were similar (P>.05). Regarding the marginal bone level changes, the 2 loading protocols also reached a comparable clinical outcome (P>.05).

CONCLUSIONS

Early implant loading should achieve the same clinical efficacy as the delayed loading method.

Heterogeneity of outcomes in randomized controlled trials on implant prosthodontic therapy is hindering comparative effectiveness research: meta-research study

BACKGROUND

Consistency in outcomes across clinical trials allows for comparing and combining results from different studies. A core outcome set (COS), representing a minimally agreed standardized group of outcomes that should be monitored and measured through research in a specific field of medicine, is not yet available for trials in implant prosthodontic (dental implant) therapy. This meta-research study aimed to analyze outcomes used in clinical trials on implant prosthodontic therapy.

METHODS

We searched the Cochrane Oral Health Group (COHG) register to identify systematic reviews of interventions in implant prosthodontic therapy published by October 2023. From the randomized controlled trials (RCTs) included in the relevant reviews, we extracted data on the characteristics of the included trials and the outcomes used. We categorized outcomes into domains.

RESULTS

From 182 systematic reviews in the COHG register, we included 11 systematic reviews on dental implant therapy. The reviews included 117 unique RCTs with 4725 participants, published from 1995 to 2020, which analyzed 74 different outcomes. Using different definitions, implant failure was analyzed in 73 RCTs. Seventeen RCTs did not define implant failure. Failure was most often (30 RCTs) followed up for one year. Only one RCT assessed implant failure after five years. Trials used 17 definitions of implant failure, while 17 trials did not report on the criteria of implant failure. Complications were analyzed in 48 RCTs, although they were not clearly defined in 12 RCTs. Failure of prosthodontic supra-structure was analyzed in 74 RCTs, with definitions of failure and criteria not clearly defined in 44 RCTs. Trials considered adverse events, peri-implant tissue health, patient attitudes, and other outcomes, including cost, aesthetics, or procedure duration. These outcomes were often different between trials. Twenty-six outcomes were used only once per study.

CONCLUSIONS

Clinical trials in implant prosthodontics used different outcomes, different definitions of outcomes and used different times to monitor them. Standardization of outcomes is necessary to allow comparability and evidence synthesis about the effectiveness of implant prosthodontic therapy.

Implant loss and crestal bone loss in early loading versus delayed and immediate loading in edentulous mandibles. A systematic review and meta-analysis

Background

Information about the risk of early loss and crestal bone loss of dental implants which have been loaded early is scant if compared with data available for those conventionally or immediately loaded. A meta-analysis of early loss and crestal bone loss in immediate or delayed loaded full mandibular denture retaining dental implants has been recently published. It is interesting to evaluate also the risks of early versus immediate and delayed loading in complete mandibular restorations. The purpose of this systematic review and meta-analysis was to study early (EL) versus immediate (IL) and delayed loading (DL) protocols in edentulous mandibles to determine whether differences exist in implant success and crestal bone loss.

Material and Methods

The literature review was conducted in PubMed, Web of Science, and the Cochrane Library. Seven randomized clinical trials were included.

Results

The result of a meta-analysis of implant loss before 1 year in EL versus IL was 0.34 (95% CI: 0.08, 1.52), favoring the EL control group, while the outcome for crestal bone loss at the three-year observation was -0.10 (95% CI: -0.28, 0.09), with a tendency toward reduced bone loss for EL. In the EL versus DL group, the result of the meta-analysis of implant loss before one year was inconclusive, while in the comparison regarding crestal bone loss in the first year of observation, the result was -0.03 (95% CI: -0.08,-0.02) with a tendency to less bone loss in EL.

Conclusions

The risk of early implant loss in the IL group was higher than in the EL group. The results in terms of early implant loss in EL versus DL are inconclusive. Besides, crestal bone loss is greater in immediately and delayed loaded implants, at 1 and 3 years of observation, compared to those loaded early.

Key words:Dental implants, early dental implant loading, dental prostheses, implant- supported, alveolar bone loss, meta-analysis.

Role of New Hydrophilic Surfaces on Early Success Rate and Implant Stability: 1-Year Post-loading Results of a Multicenter, Split-Mouth, Randomized Controlled Trial

OBJECTIVE

 To compare early implant failure and implant stability of one-stage Hiossen ET III implants with its new hydrophilic (NH) surface, compared with Hiossen ET III implants with the sandblasted and acid-etched (SA) surface at 1-year follow-up.

MATERIALS AND METHODS

 This study was designed as a split-mouth, multicenter randomized controlled trial aimed to compare SA surface implants (SA group) and NH surface, (NH group). Outcomes were implant and prosthetic survival rates, complications, the insertion torque at implant placement, and implant stability quotient (ISQ) values.

RESULTS

 Twenty-nine patients (mean age 59.9 ± 11.3 years) were treated and followed up to 1 year after loading. No patient dropped out. Fifty-eight implants (29 SA group and 29 NH group) were placed. No implants or prostheses failed and no complications were experienced during follow-up. The mean insertion torque was 40.5 ± 3.23 (38.17-41.83) Ncm in the SA group and 40.48 ± 3.49 (38.02-41.98) Ncm in the NH group (p = 0.981). There was a statistically significant difference at the second week (T2) with higher values in the NH group (p = 0.041). Similar results were found in the maxilla (p = 0.045), but not in the mandible (p = 0.362). A positive correlation was found between initial insertion torque and ISQ with higher value in the NH group (0.73 vs. 0.66).

CONCLUSIONS

 NH implants are a viable alternative to SA surface, as they seem to avoid the ISQ drop during the bone remodeling phase.

Immediate vs conventional loading of mandibular overdentures: A comprehensive systematic review and meta-analysis of randomized controlled trials

Clinicians treating overdenture patients need to know if immediate loading and conventional loading results in similar outcomes. This study aimed to perform a systematic literature search of studies comparing immediate and conventional loading of mandibular overdentures irrespective of the number of implants and conduct a meta-analysis of implant failure and marginal bone loss (MBL). A literature search of PubMed, ScienceDirect, Ovoid, Springer, and Google Scholar databases was performed for randomized controlled trials (RCTs) comparing immediate vs conventional loading of mandibular overdentures. The primary outcome was implant failure and the secondary outcome was marginal bine loss (MBL). A descriptive analysis was performed for other outcomes. Thirteen trials were included. Only one trial compared the immediate and delayed loading of single implant-supported overdenture. Seven trials used two implants, one trial used three implants while four trials used four implants. Meta-analysis indicated no statistically significant difference in implant failure and MBL between immediate and conventional loading of two-implant and four-implant supported overdentures. Descriptive analysis indicated no difference in peri-implant tissue indices, implant stability, and quality of life outcomes between the two loading protocols.There may be no difference in implant failure and MBL with immediate loading or conventional loading of two and four-implant supported mandibular overdentures. Literature review indicates that there may be no difference in peri-implant tissue indices, implant stability, and QoL outcomes between the two loading protocols. The overall quality of evidence is moderate. Further, adequately powered RCTs are required to strengthen the evidence.

Immediate versus early loading protocols of titanium-zirconium narrow-diameter implants for mandibular overdentures in edentulous patients: 1-year results from a randomized controlled trial

OBJECTIVES

The purpose of this randomized clinical trial was to compare immediate and early loading protocols for mandibular overdentures with two-splinted narrow-diameter implants in thin, non-augmented residual ridge situations.

MATERIAL AND METHODS

Each edentulous patient received two implants in the interforaminal region. If primary stability after implant placement was achieved, patients were randomized either to the immediate (48 hr post-surgery) or the early (2 weeks after surgery) loading group. In prosthetic rehabilitation, a bar prosthetic system with a titanium bar was used. Implant survival, success rates, and radiographic changes at the crestal bone level were evaluated after 1 year, and patient satisfaction was recorded at 1 and 6 months post-surgery.

RESULTS

Twenty-four patients with a mean age of 67 ± 9 years were included. One patient passed away after 11 months due to treatment-independent reasons. In the 24 implants of the immediate loading group, the mean bone level change from surgery/loading to the first-year evaluation was 0.32 ± 0.80 mm (p = .066). Regarding the early group (22 implants), the mean bone level change from loading to 1 year was 0.34 ± 0.69 mm (p = .048). After 1 year, no differences could be detected between groups (p = .91) with a mean difference of 0.02 mm (95% CI: [-0.42, 0.47]). The mean implant survival and success rates were 100% for both groups. Patient satisfaction was high; however, at 6 months, there was a difference between groups regarding the ability to chew.

CONCLUSIONS

Both loading protocols for mandibular overdentures supported by two-splinted narrow-diameter implants were successful at the 1-year follow-up.

Do the New Hydrophilic Surface Have Any Influence on Early Success Rate and Implant Stability during Osseointegration Period? Four-Month Preliminary Results from a Split-Mouth, Randomized Controlled Trial

OBJECTIVE

The objective of this study is to compare the implant stability of Hiossen ET III implants with its new hydrophilic (NH) surface and Hiossen ET III implants with the sandblasted and acid-etched (SA) surface.

MATERIALS AND METHODS

Patients required at least two teeth to be rehabilitated with a fixed, implant-supported restoration, consecutively enrolled. Patients randomly received SA surface implants (SA group) or SA implants with a newly developed bioabsorbable apatite nanocoating (NH group). Outcome measures were implant and prosthetic survival rate, complications, insertion torque, and implant stability quotient (ISQ) measured at implant placement and every week up to 8 weeks after implant placement. Comparison between groups was made by unpaired t-test, while the comparison between each follow-up will be made by paired t-tests to detect any change during the follow-up. Complications and failures were compared using Fisher's exact test.

RESULTS

A total of 14 patients were treated with 28 implants (14 SA and 14 NH). No implant and prosthesis failed 4 months after implant placement. No complications were experienced. At the 2nd week after implants placement, two implants in the SA group showed discontinuous measurements versus none in the NH group (p = 0.4815). Implants unscrewed during ISQ measurements and were rescrewed. Data recording stopped for 6 weeks. Both implants osseointegrated without any further complication. The NH implants did not show physiological ISQ decrease between 2nd and 4th week after implant placement, showing a more even pattern of ISQ values compared with SA implants (77.1 ± 4.6 vs. 72.9 ± 11.5; difference: 4.2 ± 12.1; p = 0.258). High ISQ values were found in both groups at each time point.

CONCLUSIONS

NH implants are a viable alternative to SA surface, as they seem to avoid the ISQ drop during the remodeling phase.

Effect of implant loading protocols on failure and marginal bone loss with unsplinted two-implant-supported mandibular overdentures: systematic review and meta-analysis

The aim of this study was to compare implant failure and radiographic bone level changes with different loading protocols for unsplinted two-implant-supported mandibular overdentures. An electronic search of two databases (PubMed, Cochrane Library) was performed, without language restriction, to identify randomized controlled trials (RCTs) comparing immediate or early versus conventional dental implant loading protocols for unsplinted two-implant-supported mandibular overdentures. Data were extracted independently by two reviewers. The Cochrane tool was used to assess the quality of included studies. A meta-analysis was performed. Eight RCTs were identified, seven of which were included; one trial was excluded because related outcomes were not measured. Four of the seven studies were considered to have a high risk of bias and three an unclear risk. Meta-analysis revealed no difference between immediate versus conventional or early versus conventional implant loading protocols regarding implant failure (risk difference (RD) -0.02, 95% confidence interval (CI) -0.13 to 0.10; RD 0.09, 95% CI -0.03 to 0.20) or marginal bone loss (mean difference (MD) 0.09, 95% CI -0.10 to 0.28; MD -0.05, 95% CI -0.12 to 0.02) for implants supporting mandibular overdentures. These findings should be interpreted with great caution given the serious numerical limitations of the studies included.

A randomized, 12-month controlled trial to evaluate non-inferiority of early compared to conventional loading of modSLA implants in single tooth gaps

Background

The aim of the study was to evaluate whether early loading of implants with a chemically modified sandblasted, large-grit, acid-etched (SLA) (SLActive®) surface was non-inferior to conventional loading in terms of change in crestal bone level.

Methods

This was a randomized, controlled, multicenter study. Patients requiring single-tooth rehabilitation in the posterior maxilla or mandible received implants and were randomized to receive a provisional restoration in occlusal load after 25 ± 3 days (early loading) or after 13 ± 1 weeks (conventional loading). The primary endpoint was change in crestal bone level between implant placement (baseline) and 6 months. Secondary endpoints included change in crestal bone level between baseline and 12 months, implant survival and success rates, and patient satisfaction.

Results

Of the 84 patients enrolled, 78 received implants and were randomized onto the early loading (41 patients) and conventional loading (37 patients) groups. The mean change in crestal bone level between baseline and 6 months was 0.56 ± 0.58 and 0.51 ± 0.62 mm for early and conventional loading, respectively; at 12 months, the mean change was 0.76 ± 0.60 and 0.73 ± 0.77 mm, respectively. Implant survival and success at 12 months were 100 % for both groups. Patient satisfaction was similar between the groups, except that more patients in the early loading group were satisfied or highly satisfied with the time taken for fitting.

Conclusion

The study demonstrated that early implant loading was non-inferior to conventional implant loading in terms of crestal bone level change in a Japanese patient population in short follow-up period and single tooth gaps in molar regions.

Clinical efficacy of early loading versus conventional loading of dental implants

The aim of this study was to determine the clinical differences between early and conventional loading protocols for dental implants. A comprehensive search of the Medline, Embase, and OVID databases for studies published through January 10, 2015 was conducted. Fourteen studies were included in our analysis. We found that early loading imposed a significantly higher risk of implant failure than did conventional loading (risk ratio = 2.09, 95% confidence interval [CI] [1.18, 3.69], P = 0.01), while no significant differences between the methods were found with regards to the marginal bone loss (weighted mean differences [WMD] = 0.11, 95% CI [-0.07, 0.28], P = 0.23), periotest value (WMD = 0.02, 95% CI [-0.83, 0.87], P = 0.96), or implant stability quotient (WMD = 0.79, 95% CI [-0.03, 1.62], P = 0.06). As for the health status of the peri-implant tissue, conventionally loaded implants demonstrated better performance than did early loaded implants. Subgroup analyses demonstrated that the sample size, time of publication, loading definition, implant position, extent, and restoration type influenced the results. Although early implant loading is convenient and comfortable for patients, this method still cannot achieve the same clinical outcomes as the conventional loading method.

Stability of edentulous, atrophic mandibles after insertion of different dental implants. A biomechanical study

OBJECTIVES

Fractures of the atrophic edentulous mandible are a rare complication that can become severe after the insertion of dental implants. This in vitro study investigated the effects of different implant settings varying in number, diameter, and length. and the influence of a fixed bar.

MATERIALS AND METHODS

In biomechanical experiments on artificial mandibles, an unmodified reference group, four implant settings with two different implants, and the effect of adding a fixed bar to these settings were tested. All specimens were loaded with incisal biting forces until failure due to fracture.

RESULTS

Implants weakened all specimens significantly compared with those in the reference group. Without a fixed bar, four short and thick implants showed the best results, with high significance. With a fixed bar, four long and thin implants withstood the highest loads. The addition of fixed bars reduced the differences between the implant settings. Fixed bars did not show increased stability for all groups; however, these groups showed a higher mean strength.

CONCLUSIONS

Four implants with a short and thick design should be the first choice when implants are placed without a fixed bar in an atrophic mandible. With a fixed bar, four long and thin implants should be used.

Efficacy of standard (SLA) and modified sandblasted and acid-etched (SLActive) dental implants in promoting immediate and/or early occlusal loading protocols: a systematic review of prospective studies

OBJECTIVE

To assess the survival percentage, clinical and radiographic outcomes of sandblasted and acid-etched (SLA) dental implants and its modified surface (SLActive) in protocols involving immediate and early occlusal loading.

METHODS

MEDLINE, EMBASE and the Cochrane Oral Health Group's Trials Register CENTRAL were searched in duplicate up to, and including, June 2013 to include randomised controlled trials (RCTs) and prospective observational studies of at least 6-month duration published in all languages. Studies limited to patients treated with SLA and/or SLActive implants involving a treatment protocol describing immediate and early loading of these implants were eligible for inclusion. Data on clinical and/or radiographic outcomes following implant placement were considered for inclusion.

RESULTS

Of the 447 potentially eligible publications identified by the search strategy, seven RCTs comprising a total of 853 implants (8% titanium plasma-sprayed, 41.5% SLA and 50.5% SLActive) and 12 prospective observational studies including 1394 SLA and 145 SLActive implants were included in this review. According to the Cochrane Collaboration's tool for assessing risk of bias, one of the studies was considered to be at a low risk of bias, whereas the remaining studies were considered to be at an unclear risk. Regarding the observational studies, all of them presented a medium methodological quality based on the Modified Newcastle-Ottawa scale. There were no significant differences reported in the studies in relation to implant loss or clinical parameters between the immediate/early loading and delayed loading protocols. Overall, 95% of SLA and 97% of SLActive implants still survive at the end of follow-up.

CONCLUSIONS

Despite of the positive findings achieved by the included studies, few RCTs were available for analysis for SLActive implants. Study heterogeneity, scarcity of data and the lack of pooled estimates represent a limitation between studies' comparisons and should be considered when interpreting the present findings.

The effect of age, gender, and insertion site on marginal bone loss around endosseous implants: results from a 3-year trial with premium implant system

Objectives. The goal of this study was to evaluate bone changes around endosseous implants in partially edentulous patients. Materials and Methods. A total of 632 two-stage implants were placed in 252 patients. The implants had straight emergence profile, ZirTi surface, 3.3 to 5 mm diameter, and 8.5 to 13 mm length. Bone levels were assessed on orthopantomography immediately after surgery and after 36 months and marginal bone loss (MBL) was calculated from their difference. Results. Cumulative survival rate was 98.73%. Overall MBL was 0.8 mm ± 0.03 (mean ± SEM). Higher MBL was observed around implants in the maxilla than in the mandible (P < 0.007). A relation between implant diameter and MBL (P < 0.0001) was observed in male and, more limitedly, female patients. Older patients had higher MBL in the maxilla, but not in the mandible (P < 0.0001). MBL progressively increased with age in male patients, but reached a peak already in the 50–60 years age group in the female subset (P < 0.001). Conclusions. The overall MBL is consistent with the available literature. Site difference and patient age and gender appear to significantly affect MBL, representing important factors to be considered during implant placement.

Reasons for failures of oral implants

This study reviews the literature regarding the factors contributing to failures of dental implants. An electronic search was undertaken including papers from 2004 onwards. The titles and abstracts from these results were read to identify studies within the selection criteria. All reference lists of the selected studies were then hand-searched, this time without time restrictions. A narrative review discussed some findings from the first two parts where separate data from non-comparative studies may have indicated conclusions different from those possible to draw in the systematic analysis. It may be suggested that the following situations are correlated to increase the implant failure rate: a low insertion torque of implants that are planned to be immediately or early loaded, inexperienced surgeons inserting the implants, implant insertion in the maxilla, implant insertion in the posterior region of the jaws, implants in heavy smokers, implant insertion in bone qualities type III and IV, implant insertion in places with small bone volumes, use of shorter length implants, greater number of implants placed per patient, lack of initial implant stability, use of cylindrical (non-threaded) implants and prosthetic rehabilitation with implant-supported overdentures. Moreover, it may be suggested that the following situations may be correlated with an increase in the implant failure rate: use of the non-submerged technique, immediate loading, implant insertion in fresh extraction sockets, smaller diameter implants. Some recently published studies suggest that modern, moderately rough implants may present with similar results irrespective if placed in maxillas, in smoking patients or using only short implants.

Comparative evaluation of bone in mandibular implant retained overdentures using delayed and immediate loading protocol: an in-vivo study

The aim of the present study was to evaluate the changes in periimplant bone quality, crestal bone level and the implant stability (periotest) for mandibular implant retained overdentures with ball attachments using delayed and immediate loading protocols. Ten completely edentulous patients had two alpha bio dental implants placed in the anterior part of the mandible. The loading protocols for the patients was chosen randomly by drawing lots. Five patients were loaded under immediate loading protocols and other five following delayed. Crestal bone loss and bone quality were assessed around each implant. Periotest values were recorded for each implant at 3, 6 and 12 months after loading. Two implants were lost and were excluded from the study. However mean crestal bone loss around implants was 0.81 mm from the time of prosthetic loading to 12 months after prosthetic loading was seen and no significant result was found between the two groups for the crestal bone loss and the periotest values. Though the periotest value decreased (indicates increased stability) over the time period. The bone density changes were significant for both the groups at coronal level at all time intervals but at middle level significant only after 12 months of prosthetic loading, although individual variation was high. This study concluded that the changes in crestal bone level and periotest values were insignificant for the two groups. But the implant stability increased over the time and the crestal bone loss was evident with decreased rate over the period of time. There was wide individual variation for the bone density changes but overall increase in the density was seen.

Immediate loading of overdentures: systematic review

INTRODUCTION

The goal of implant treatment is the formation of a direct bone-implant interface contact.

PURPOSE

This study aimed to evaluate the possibilities of immediate loading treatment for edentulous patients rehabilitated with mandibular and maxillary overdentures.

MATERIAL AND METHODS

A literature review using the PubMed and BIREME databases between the periods of 1977 and 2011 was performed.

RESULTS

From an initial yield of 218 titles, 78 articles were selected for text analysis, finally resulting in 23 studies (16 prospective, 6 prospective randomized, and 1 prospective multicenter) that met the inclusion criteria.

CONCLUSION

The immediate loading protocol through which the implants are subjected to occlusal function immediately after their placement was introduced to overcome this limitation.

Early loading of single-piece implant for partially edentulous posterior arch: a prospective one-year case report

Implant therapy is now well established, and there is an increasing need for shorter rehabilitation time. Original prerequisites of osseointegration have been reassessed to satisfy continuously increasing patient's expectation of reduced treatment time, improved esthetics, and increased comfort. Shorter healing time may be appropriate in some circumstances, and examples of early loading have been reported in animal and human studies. However, to date there are insufficient data to determine a universally acceptable opinion on early loading of implants for single-tooth replacement. This case report involves early loading, combined with construction of a restoration, inserted directly after 6 weeks of implant surgery and followup of one year.

Interventions for replacing missing teeth: different times for loading dental implants

BACKGROUND

To minimise the risk of implant failures after their placement, dental implants are kept load-free for 3 to 8 months to establish osseointegration (conventional loading). It would be beneficial if the healing period could be shortened without jeopardising implant success. Nowadays implants are loaded early and even immediately and it would be useful to know whether there is a difference in success rates between immediately and early loaded implants compared with conventionally loaded implants.

OBJECTIVES

To evaluate the effects of (1) immediate (within 1 week), early (between 1 week and 2 months), and conventional (after 2 months) loading of osseointegrated implants; (2) immediate occlusal versus non-occlusal loading and early occlusal versus non-occlusal loading; (3) direct loading versus progressive loading immediately, early and conventionally.

SEARCH METHODS

The following electronic databases were searched: the Cochrane Oral Health Group's Trials Register (to 8 June 2012), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2012, Issue 4), MEDLINE via OVID (1946 to 8 June 2012) and EMBASE via OVID (1980 to 8 June 2012). Authors of identified trials were contacted to find unpublished randomised controlled trials (RCTs). There were no restrictions regarding language or date of publication.

SELECTION CRITERIA

All RCTs of root-form osseointegrated dental implants, having a follow-up of 4 months to 1 year, comparing the same implant type immediately, early or conventionally loaded, occlusally or non-occlusally loaded, or progressively loaded or not. Outcome measures were: prosthesis and implant failures and radiographic marginal bone level changes.

DATA COLLECTION AND ANALYSIS

Data were independently extracted, in duplicate, by at least two review authors. Trial authors were contacted for missing information. Risk of bias was assessed for each trial by at least two review authors, and data were extracted independently, and in duplicate. Results were combined using fixed-effect models with mean differences (MD) for continuous outcomes and risk ratios (RR) for dichotomous outcomes with 95% confidence intervals (CI). A summary of findings table of the main findings was constructed.

MAIN RESULTS

Forty-five RCTs were identified and, from these, 26 trials including a total of 1217 participants and 2120 implants were included. Three trials were at low risk of bias, 12 were at high risk of bias and for the remaining 11 the risk of bias was unclear. In nine of the included studies there were no prosthetic failures within the first year, with no implant failures in 7 studies and the mean rate of implant failure in all 26 trials was a low 2.5%. From 15 RCTs comparing immediate with convential loading there was no evidence of a difference in either prosthesis failure (RR 1.87; 95% CI 0.70 to 5.01; 8 trials) or implant failure (RR 1.65; 95% CI 0.68 to 3.98; 10 trials) in the first year, but there is some evidence of a small reduction in bone loss favouring immediate loading (MD -0.10 mm; 95% CI -0.20 to -0.01; P = 0.03; 9 trials), with some heterogeneity (Tau² = 0.01; Chi² = 14.37, df = 8 (P = 0.07); I² = 44%). However, this very small difference may not be clinically important. From three RCTs which compared early loading with conventional loading, there is insufficient evidence to determine whether or not there is a clinically important difference in prosthesis failure, implant failure or bone loss. Six RCTs compared immediate and early loading and found insufficient evidence to determine whether or not there is a clinically important difference in prosthesis failure, implant failure or bone loss. From the two trials which compared occlusal loading with non-occlusal loading there is insufficient evidence to determine whether there is a clinically important difference in the outcomes of prosthesis failure, implant failure or bone loss. We did not identify any trials which evaluated progressive loading of implants.

AUTHORS' CONCLUSIONS

Overall there was no convincing evidence of a clinically important difference in prosthesis failure, implant failure, or bone loss associated with different loading times of implants. More well-designed RCTs are needed and should be reported according to the CONSORT guidelines (www.consort-statement.org/).

Implants in bone: part I. A current overview about tissue response, surface modifications and future perspectives

PURPOSE

The aim of study paper is to present an overview of osseointegration of dental implants, focusing on tissue response, surface modifications and future perspective.

DISCUSSION

Great progress has been made over the decades in the understanding of osseous peri-implant healing of dental implants, leading to the development of new implant materials and surfaces. However, failures and losses of implants are an indicator that there is room for improvement. Of particular importance is the understanding of the biological interaction between the implant and its surrounding bone.

CONCLUSION

The survival rates of dental implants in bone of over 90 % after 10 years show that they are an effective and well-established therapy option. However, new implant materials and surface modifications may be able to improve osseointegration of medical implants especially when the wound healing is compromised. Advanced techniques of evaluation are necessary to understand and validate osseointegration in these cases. An overview regarding the current state of the art in experimental evaluation of osseointegration of implants and implant material modifications will be given in Part II.

Effect of loading time on the survival rate of anodic oxidized implants: prospective multicenter study

PURPOSE

The purpose of this prospective study was to evaluate the effect of early loading on survival rate or clinical parameter of anodic oxidized implants during the 12-month postloading period.

MATERIALS AND METHODS

Total 69 implants were placed in 42 patients. Anodic oxidized implants (GS II, Osstem Cor., Busan, Korea) placed on the posterior mandibles were divided into two groups, according to their prosthetic loading times: test group (2 to 6 weeks), and control group (3 to 4 months). The implant survival rates were determined during one-year postloading period and analyzed by Kaplan-Meier method. The radiographic peri-implant bone loss and periodontal parameters were also evaluated and statistically analyzed by unpaired t-test.

RESULTS

Total 69 implants were placed in 42 patients. The cumulative postloading implant survival rates were 88.89% in test group, compared to 100% in control group (P<.05). Periimplant marginal bone loss (T: 0.27±0.54 mm, C: 0.40±0.55 mm) and periodontal parameters showed no significant difference between the groups (P>.05).

CONCLUSION

Within the limitation of the present study, implant survival was affected by early loading on the anodic oxidized implants placed on posterior mandibles during one-year follow-up. Early implant loading did not influence peri-implant marginal bone loss, and periodontal parameters.

The effect of maximum bite force, implant number, and attachment type on marginal bone loss around implants supporting mandibular overdentures: a retrospective study

BACKGROUND

There remains controversy regarding the clinical reasons for late-implant bone loss, which is a critical factor in the long-term success of implant-supported overdentures.

PURPOSE

Assessment of the effect of such factors as attachment type, number of implants, gender, age, and maximum bite force (MBF) on marginal bone loss (MBL) around implants supporting mandibular overdentures.

MATERIALS AND METHODS

Sixty-two edentulous patients rehabilitated with two-, three-, or four-implant-supported mandibular overdentures at a university clinic between January 2006 and January 2007 and having a digital panoramic radiograph at the time of loading, were included in this study. All patients received digital panoramic radiographs, and MBL was measured by subtracting bone levels from the first radiograph. MBF was measured using a bite force transducer.

RESULTS

The amount of bone loss 48 months after loading was found to be unrelated to gender, age, implant number, attachment type, and splinting (p = .741, p = .953, p = .640, p = .763, p = .370, respectively). A significant correlation was observed between the MBF and the MBL of distal implants on the right side (p < .01, 79.9%) and the MBF and the MBL of distal implants on the left side (p = .011, 34.6%).

CONCLUSIONS

MBL around implants supporting mandibular overdentures seems not to be affected by number of implants, attachment type, age, or gender; however, MBL is affected by MBF.

Detecting bone loss along dental implants by subtraction of panoramic radiographs

OBJECTIVES

To test an extended subtraction method for measuring changes in bone along dental implants depicted on non-standardized panoramic radiographs.

MATERIAL AND METHODS

The measuring method consisted of a subtraction module extended with modules correcting gray values, correcting geometry and defining the region of interest mesial and distal of dental implants. It was applied to an archive of panoramic radiographs of implant patients who had been monitored up to 16 years.

RESULTS

Significant loss of gray value was demonstrated at a constant rate of 0.6 units per month throughout the study. This indicates gradual bone loss on the mesial and/or distal sides of the implants. Females were found to lose bone at a higher rate than males. Smokers and non-smokers, and various implant strategies yielded the same rate of bone loss.

CONCLUSIONS

The measuring method is a helpful tool to monitor changes around implants even when non-standardized radiographs are being used. Whereas changes of marginal bone level are increased five to eight times during the first year after surgery, the present method shows gradual loss of bone during 15 years after surgery.

A Quality-of-Life Comparison Between Self-Aligning and Ball Attachment Systems for 2-Implant–Retained Mandibular Overdentures

The aim of this study was to evaluate the self-aligning overdenture attachment system by comparing its oral health–related quality of life (OHRQL) with a traditionally used ball attachment system. In this randomized, within-subject crossover trial, 25 edentulous subjects each received 2 mandibular implants, and were then assigned to receive either self-aligning or traditional ball attachments. After 3 months, all subjects were switched to the second attachment type. The OHRQL was evaluated for both of the treatments using the short form of the Oral Health Impact Profile (OHIP-14). A subanalysis among subjects with below-average space available for attachment placement was also performed. Wilcoxon signed-rank test was used to compare differences between groups. Scores on the OHIP-14 physical disability domain were significantly better for the self-aligning attachment system (P  =  .049). Among subjects with below-average attachment space, functional limitation, psychological discomfort, physical disability, psychological disability, and total OHIP-14, scores were significantly better for the self-aligning attachment system (P  =  .041, P  =  .047, P  =  .048, P  =  .026, and P  =  .005, respectively). The self-aligning attachment system for 2-implant–retained mandibular overdentures is equal or superior to traditional ball attachments in all domains of the OHIP-14.

Osseointegration of titanium implants with a roughened surface containing hydride ion in a rabbit model

OBJECTIVE

The objective of this study was to investigate the effect of hydride ion on bone formation and bone-bonding strength at the early stage of implantation.

STUDY DESIGN

Implants and plates were treated in 2 ways: test implant (implant surface with hydride ion) and control implant (implant surface without hydride ion). Crystal structure of plate surfaces was analyzed by low angle x-ray diffractometry (XRD). Sixty implants (30 test implants and 30 control implants) were inserted into tibias of 10 rabbits. At 2 and 8 weeks postimplantation, tibias were retrieved and prepared for removal torque tests (RTQ) and histomorphometric evaluation, respectively.

RESULTS

TiH(2) diffractions appeared on the XRD pattern of the test surface whereas TiH(2) did not appear on the control surface. The test implants showed 51.28% and 64.63% greater RTQ values than did the control implants at 2 and 8 weeks (P = .010, .011, respectively). Histomorphometric evaluation demonstrated the test implants significantly increased bone-implant contact and peri-implant bone formation at 2 and 8 weeks.

CONCLUSION

These results suggest the presence of hydride ion in the implant surface may improve bone integration with implant surfaces at the early stage of implantation.

The Role of Timing of Loading on Later Marginal Bone Loss Around Dental Implants: A Retrospective Clinical Study

The aim of this study was to assess the relation between marginal bone loss (MBL) around dental implants after a loading period of 36 months and the timing of loading. A total of 87 patients with 252 implants were included in the study group. The time span from implant placement to beginning of loading of the implants was evaluated. Delay of loading of implants seems to increase MBL around dental implants as the result of disuse atrophy. Implants next to a tooth on 1 or 2 sides suffered less from MBL. No statistically significant difference in MBL rate was noted between single and splinted implants or between smooth collar and microgeometry neck implants. Results of this study encourage early loading, especially for the mandibular overdenture supporting implants.

Loading protocols for mandibular implant overdentures: a systematic review with meta-analysis

BACKGROUND

Mandibular overdentures are a successful treatment option for the edentulous patients with long-term predictable outcomes, using conventional loading protocols. Currently, both early and immediate loading protocols for mandibular implant overdentures are prevalent in the literature.

PURPOSE

A systematic review and meta-analysis of the current published literature on comparative studies using conventional versus either early and/or immediate loading protocols for mandibular implant overdentures.

MATERIALS AND METHODS

The review was carried out in accordance with the QUOROM (Quality of Reporting of Meta-Analyses) guidelines. The PICO (Population, Intervention, Comparisons, Outcomes) format was used in conjunction with predefined inclusion criteria. A literature search of PubMed (1969-October 2008), EMBASE (1998-October 2008), the Cochrane Database of Systematic Reviews, and the Cochrane Controlled Trial Register was conducted. In addition, hand searching through refereed dental journals was also performed for the years 2000 to 2008. The meta-analysis was conducted by using the MIX software v.1.7 (Kitasato Clinical Research Center, Kanagawa, Japan).

RESULTS

A total of 191 studies were identified through the electronic search. After full-text screening and cross-matching with the predefined inclusion criteria, only 10 studies with a minimum follow-up of 2 years were eligible for inclusion in this review. Of the 10 included studies, seven have compared the outcome of conventional versus early loading of implants supporting mandibular overdentures. The remaining three studies, on the other hand, compared the outcome of conventional versus immediate loading. The meta-analysis revealed no significant difference in the outcome between conventional and either early (p = .72) or immediate (p = .08) loading of implants supporting mandibular implant overdentures.

CONCLUSIONS

Short-term outcomes of early or immediate loading protocols for mandibular implant overdentures achieved comparable success to conventional loading ones. No evidence was found of long-term studies to support or refute either early or immediate loading protocols for mandibular implant overdentures.

Immediate loading of two implants with a mandibular implant-retained overdenture: a new treatment protocol

PURPOSE

The aim of this study was to present the clinical outcomes of the immediate loading of two bar-splinted implants retaining a mandibular overdenture.

MATERIALS AND METHODS

In a clinical trial, 124 edentulous patients were treated according to a new treatment concept, which involves the immediate loading of two bar-splinted SLActive implants with an implant-retained mandibular overdenture. The new conventional mandibular denture is used as a template for implant positioning and as an impression tray, and for mounting the retention clip by the dental laboratory. At the same day the implants are placed, the conventional denture is converted into an implant-retained overdenture. During the healing and evaluation period, resonance frequency analysis (RFA) was undertaken to assess the effect of loading on implant stability and survival.

RESULTS

The survival rate of the implants was 98.8% during the evaluation period (12-40 months). Only 3 of the 248 implants were lost. During the healing (osseointegration) phase, the implant-stability quotient increased significantly (p = .0001). During the evaluation period, four patients (3%) needed a relining of their mandibular overdenture, whereas 13 patients (11%) needed relining of the maxillary denture.

CONCLUSIONS

Two interconnected implants can be successfully loaded by a mandibular overdenture at the same day of implant placement with a high survival rate of the implants. Only a few patients needed additional relining of the overdenture. Repeated RFA measurements can be useful in gauging implant stability and survival.

Interventions for replacing missing teeth: different times for loading dental implants

BACKGROUND

To minimize the risk of implant failure, osseointegrated dental implants are conventionally kept load-free during the healing period. During healing removable prostheses are used, however many patients find these temporary prostheses rather uncomfortable and it would be beneficial if the healing period could be shortened without jeopardizing implant success. Nowadays immediately and early loaded implants are commonly used in mandibles (lower jaws) of good bone quality. It would be useful to know whether there is a difference in success rates between immediately or early loaded implants compared with conventionally loaded implants.

OBJECTIVES

To evaluate the efficacy of (1) immediate (within 1 week), early (between 1 week and 2 months), and conventional (after 2 months) loading of osseointegrated implants, and of (2) immediate occlusal versus non-occlusal loading during the bone healing phase.

SEARCH STRATEGY

The Cochrane Oral Health Group's Trials Register, CENTRAL, MEDLINE and EMBASE were searched. Handsearching included several dental journals. Authors of all identified trials, an Internet discussion group and 55 dental implant manufacturers were contacted to find unpublished randomised controlled trials (RCTs). The last electronic search was conducted on 4 June 2008.

SELECTION CRITERIA

All RCTs of root-form osseointegrated dental implants, having a follow up of 4 months to 1 year, comparing the same implant type immediately, early and conventionally loaded or occlusally and non-occlusally loaded. Outcome measures were: prosthesis and implant failures and radiographic marginal bone level changes.

DATA COLLECTION AND ANALYSIS

Data were independently extracted, in duplicate, by two review authors. Authors were contacted for details of randomisation and withdrawals and a quality assessment was carried out. The Cochrane Collaboration's statistical guidelines were followed.

MAIN RESULTS

Thirty RCTs were identified and 22 trials including 976 participants in total were included. Twelve trials compared immediate versus conventional loading, three early versus conventional loading, six immediate versus early loading, and one occlusally versus non-occlusally loaded implants. On a patient, rather than per implant basis, there were no statistically significant differences for any of the meta-analyses.

AUTHORS' CONCLUSIONS

It is possible to successfully load dental implants immediately or early after their placement in selected patients, though not all clinicians may achieve optimal results. It is unclear whether it is beneficial to avoid occlusal contacts during the osseointegration phase. Trends suggest that immediately loaded implants fail more often than those conventionally loaded, but less commonly than those loaded early. If a clinician wishes to load the implants early, it might be wiser to load them immediately (within 1 week) rather than waiting for 1 or 2 months. A high degree of primary implant stability (high value of insertion torque) seems to be one of the prerequisites for a successful immediate/early loading procedure. More well designed RCTs are needed and should be reported according to the CONSORT guidelines (www.consort-statement.org/).

Analysis of the possibility of the relationship between various implant-related measures: an 18-month follow-up study

Better clarification of the long-term relationship among the various implant-related measures could improve the evaluation process for dental implants. Thus, the aim of the present study was to determine the potential correlations among the volumetric features and nitric oxide content of peri-implant sulcus fluid (PISF) and measures of implant stability, and the marginal bone loss. Completely edentulous patients (n=15) treated with dental implants and ball attachment mandibular over dentures were included. Resonance frequency analysis (RFA), marginal bone level measurements, PISF volume and spectrophotometrically determined nitrite levels were recorded for all dental implant sites. Measures for early (n=16) and delayed (n=14) loaded dental implants were comparatively analysed for a period of 18 months. Some random correlations between PISF volume and marginal bone level, PISF nitrite level and marginal bone level and PISF volume and PISF nitrite content, and RFA and PISF volume were observed. However, the only constant correlation was noticed between implant stability (RFA scores) and marginal bone level. This correlation was negative and significant for all dental implants and for delayed loaded implants (P<0.05). The pattern of loading seemed to affect the extent, but not the pattern of this relationship. While some of the implant-related measures may be strongly associated (e.g. dental implant stability and marginal bone level), not all measures from a single implant site are likely to be related. Such associations may be under the influence of a variety of factors including the loading protocol of dental implants.

Bone responses to titanium implants surface-roughened by sandblasted and double etched treatments in a rabbit model

OBJECTIVE

The objective of this study was to investigate bone responses to titanium implants surface-roughened by sandblasted and double-etched treatments in a rabbit model.

STUDY DESIGN

Sixty implants of 10 mm in length (30 machined and 30 roughened) were inserted into femurs of 30 rabbits and 30 implants of 8 mm in length (15 machined and 15 roughened) were inserted into tibias of 15 rabbits. At 2, 4, and 8 weeks postimplantation, femurs and tibias were retrieved and prepared for removal torque tests (RTQ) and histomorphometric evaluation, respectively.

RESULTS

The roughened implants showed 66.21%, 89.06%, and 115.00% greater RTQ values than did the machined implants at 2, 4, and 8 weeks. Histomorphometric evaluation demonstrated the roughened implants significantly increased bone-implant contact and peri-implant bone formation during all observation periods.

CONCLUSION

These results suggest this surface-roughened approach provides the implant surface with a considerable osteoconductive potential promoting a high level of bone integration with bone.

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.