Esthetic outcomes following immediate and early implant placement in the anterior maxilla--a systematic review

PURPOSE

The objectives of this systematic review are (1) to quantitatively estimate the esthetic outcomes of implants placed in postextraction sites, and (2) to evaluate the influence of simultaneous bone augmentation procedures on these outcomes.

MATERIALS AND METHODS

Electronic and manual searches of the dental literature were performed to collect information on esthetic outcomes based on objective criteria with implants placed after extraction of maxillary anterior and premolar teeth. All levels of evidence were accepted (case series studies required a minimum of 5 cases).

RESULTS

From 1,686 titles, 114 full-text articles were evaluated and 50 records included for data extraction. The included studies reported on single-tooth implants adjacent to natural teeth, with no studies on multiple missing teeth identified (6 randomized controlled trials, 6 cohort studies, 5 cross-sectional studies, and 33 case series studies). Considerable heterogeneity in study design was found. A meta-analysis of controlled studies was not possible. The available evidence suggests that esthetic outcomes, determined by esthetic indices (predominantly the pink esthetic score) and positional changes of the peri-implant mucosa, may be achieved for single-tooth implants placed after tooth extraction. Immediate (type 1) implant placement, however, is associated with a greater variability in outcomes and a higher frequency of recession of > 1 mm of the midfacial mucosa (eight studies; range 9% to 41% and median 26% of sites, 1 to 3 years after placement) compared to early (type 2 and type 3) implant placement (2 studies; no sites with recession > 1 mm). In two retrospective studies of immediate (type 1) implant placement with bone graft, the facial bone wall was not detectable on cone beam CT in 36% and 57% of sites. These sites had more recession of the midfacial mucosa compared to sites with detectable facial bone. Two studies of early implant placement (types 2 and 3) combined with simultaneous bone augmentation with GBR (contour augmentation) demonstrated a high frequency (above 90%) of facial bone wall visible on CBCT. Recent studies of immediate (type 1) placement imposed specific selection criteria, including thick tissue biotype and an intact facial socket wall, to reduce esthetic risk. There were no specific selection criteria for early (type 2 and type 3) implant placement.

CONCLUSIONS

Acceptable esthetic outcomes may be achieved with implants placed after extraction of teeth in the maxillary anterior and premolar areas of the dentition. Recession of the midfacial mucosa is a risk with immediate (type 1) placement. Further research is needed to investigate the most suitable biomaterials to reconstruct the facial bone and the relationship between long-term mucosal stability and presence/absence of the facial bone, the thickness of the facial bone, and the position of the facial bone crest.

Implant placement and loading protocols in partially edentulous patients: A systematic review

OBJECTIVES

To systematically review the evidence for the clinical outcome of fixed implant prostheses treated with different combinations of implant placement and loading protocols in partially edentulous patients.

MATERIALS AND METHODS

An electronic search was performed in Medline, Embase, and Central to identify studies investigating the outcome of implants subjected to immediate placement + immediate restoration/loading (Type 1A), immediate placement + early loading (Type 1B), immediate placement + conventional loading (Type 1C), early placement + immediate restoration/loading (Type 2-3A), early placement + early loading (Type 2-3B), early placement + conventional loading (Type 2-3C), late placement + immediate restoration/loading (Type 4A), late placement + early loading (Type 4B), late placement + conventional loading (Type 4C) with implant-supported fixed dental prostheses (IFDPs) in partially edentulous patients. Only human studies with at least 10 cases and a minimum follow-up time of 12 months, reporting on solid-screw-type implants with rough surfaces and an intra-osseous diameter between 3 and 6 mm, were included. A cumulative survival rate for each type of the implant placement and loading protocols was weighted by the duration of follow-up and number of implants.

RESULTS

The search provided 5,248 titles from which 2,362 abstracts and 449 full-text articles were screened. A total of 69 publications that comprised 23 comparative studies (15 randomized controlled trials, 7 controlled clinical trials) and 47 noncomparative studies (34 prospective cohort studies, 13 retrospective cohort studies) were included for analysis. Considerable heterogeneity in study design was found, and therefore, a meta-analysis of controlled studies was not possible. The weighted cumulative survival rate of each type of placement and loading protocol was 98.4% (Type 1A), 98.2% (Type 1B), 96.0% (Type 1C), 100% (Type 2-3B), 96.3% (Type 2-3C), 97.9% (Type 4A), 98.3% (Type 4B), and 97.7% (Type 4C). Type 1C, Type 2-3C, Type 4B, and Type 4C were scientifically and clinically validated (SCV). Type 1A, Type 1B, and Type 4A were clinically documented (CD), and Type 2-3A and Type 2-3B were clinically insufficiently documented (CID).

CONCLUSIONS

Evaluating outcomes in oral implantology by combining the placement and loading protocols are paramount. The selected loading protocol appears to influence the outcome of immediate implant placement.

Immediate implant placement and provisionalization of maxillary anterior single implants

An inevitable loss of soft and hard tissue after tooth extraction often results in a compromised site for anterior implant esthetics in both vertical and horizontal dimensions. Immediate implant placement and provisionalization has been a viable option for replacing failing maxillary anterior teeth as it preserves the vertical existing osseous and gingival architecture. With the simultaneous addition of soft- and hard-tissue grafts, the peri-implant horizontal tissue topography can also be maintained. The esthetic success of immediate implant placement and provisionalization procedures is influenced by a number of factors that can be identified as patient-dependent or clinician-dependent. This article describes in detail the process of patient selection, indications, contraindications, diagnosis, treatment planning and treatment execution required to achieve functional and esthetic success with immediate implant placement and provisionalization.

Implant loading protocols for edentulous patients with fixed prostheses: a systematic review and meta-analysis

PURPOSE

To report on the effect of immediate implant loading with fixed prostheses compared to early and conventional loading on implant and prosthesis survival, failure, and complications.

MATERIALS AND METHODS

An electronic and manual search was conducted to identify randomized controlled clinical trials (RCTs) as well as prospective and retrospective studies involving rough surface implants and implant fixed complete dental prostheses for edentulous patients.

RESULTS

The 62 studies that fulfilled the inclusion criteria featured 4 RCTs, 2 prospective case-control studies, 34 prospective cohort studies, and 22 retrospective cohort studies. These studies yielded data from 2,695 patients (2,757 edentulous arches) with 13,653 implants. Studies were grouped according to the loading protocol applied; 45 studies reported on immediate loading, 8 on early loading, and 11 on conventional loading. For the immediate loading protocol with flap surgery, the implant and prosthesis survival rates ranged from 90.1% to 100% and 93.75% to 100%, respectively (range of follow-up, 1 to 10 years). When immediate loading was combined with guided flapless implant placement, the implant survival rates ranged from 90% to 99.4%. For the early loading protocol, the implant and prosthesis survival rates ranged from 94.74% to 100% and 93.75% to 100%, respectively (range of follow-up, 1 to 10 years). For the conventional loading protocol, the implant and prosthesis survival rates ranged from 94.95% to 100% and 87.5% to 100%, respectively (range of follow-up, 2 to 15 years). No difference was identified between maxilla and mandible.

CONCLUSIONS

When selecting cases carefully and using dental implants with a rough surface, immediate loading with fixed prostheses in edentulous patients results in similar implant and prosthesis survival and failure rates as early and conventional loading. For immediate loading, most of the studies recommended a minimal insertion torque of 30 Ncm. The estimated 1-year implant survival was above 99% with all three loading protocols. Caution is necessary when interpreting these results, as there are many confounding factors that affect treatment outcomes with each of the loading protocols.

Implant placement in the esthetic area: criteria for positioning single and multiple implants

Patient expectations from implant treatment have changed over the years and esthetics plays an important role in defining what is now called success of rehabilitation. Of the many factors that influence the outcome of the rehabilitation, the two main ones are the bone and soft-tissue deficiencies at the intended implant site. Many surgical approaches are described in terms of timing of implant placement and management of regenerative procedures. The aim of this article is to discuss the different implant placement alternatives in the esthetic area, in particular: (i) the timing of implant placement/regenerative procedures/skeletal growth/altered passive eruption; (ii) the correct three-dimensional position of the fixture between the cuspids and in the premolar area; (iii) multiple missing teeth in the esthetic area with single tooth/pontic or cantilevered options/prosthetic compensation; (iv) placement of implants into infected sites; and (v) the influence of abutment and crown morphology on implant position. Combining our long-standing clinical experience and the pertinent literature, the following conclusions can be drawn: Immediate implant placement can be a successful procedure in terms of esthetics but it is technique sensitive and requires an experienced team. Immediate placement is less traumatic to the patient as fewer surgical procedures are involved and patients tend to prefer this clinical approach with regards to quality of life. The diagnostic phase is of utmost importance, with not only bone and soft tissue deficiencies being addressed but also: skeletal growth, dental/implant soft tissue parameters such as altered passive eruption and the morphology of the roots adjacent to the edentulous area. Post-extraction immediate loading is feasible in infected sites. The correct position of the fixture should follow widely accepted guidelines but the abutment morphologies play a role in the vestibular/palatal position of the implant. The long axis of the implant, aiming at the incisal edge of the future restorations, is the most appropriate implant position when a shoulder-less abutment is used and allows a restorative crown morphology with a cervical contour resembling a natural tooth. The use of a shoulder-less abutment gives more space for the tissue to grow compared with the traditional abutment with shoulder finish line.

Loading protocols for single-implant crowns: a systematic review and meta-analysis

PURPOSE

To test whether or not immediate loading of single-implant crowns renders different results from early and conventional loading with respect to implant survival, marginal bone loss, stability of peri-implant soft tissue, esthetics, and patient satisfaction.

MATERIALS AND METHODS

An electronic search of Medline and Embase databases including studies published prior to August 1, 2012, was performed and complemented by a manual search. Randomized controlled trials (RCTs) comparing different loading protocols of single-implant crowns with a follow-up after restoration of at least 1 year were included. A meta-analysis yielded odds ratios (OR) and standardized mean differences (SMD) together with the corresponding 95% confidence intervals (95% CI).

RESULTS

The search provided 10 RCTs comparing immediate and conventional loading and 1 RCT comparing immediate and early loading. When assessing the implant survival at 1 year of loading, the meta-analysis of 10 studies found no significant differences between immediate and conventional loading (OR = 0.75; 95% CI: 0.32 to 1.76). The total difference of marginal bone loss during the first year of function between immediate and conventional loading protocols in 7 RCTs did not reach statistical significance (SMD = -0.05 mm; 95% CI: -0.41 to 0.31 mm). There were no significant differences between immediate and conventional loading regarding implant survival and marginal bone loss at 2, 3, and 5 years of loading. Three RCTs comparing the change of papilla level between immediate and conventional loading identified no significant differences. One study investigated the recession of the buccal mucosa after implant placement and found significantly inferior soft tissue loss for immediate loading as compared to conventional loading. Two RCTs investigated the recession of the buccal mucosa after insertion of the definitive crown and found no differences between immediate and conventional loading. The esthetics and the patient satisfaction were assessed in one and two RCTs, respectively. There were no significant differences between immediate and conventional loading.

CONCLUSIONS

Immediately and conventionally loaded single-implant crowns are equally successful regarding implant survival and marginal bone loss. This conclusion is primarily derived from studies evaluating implants inserted with a torque ≥ 20 to 45 Ncm or an implant stability quotient (ISQ) ≥ 60 to 65 and with no need for simultaneous bone augmentation. Immediately and conventionally loaded implants do not appear to differently affect the papilla height during the first year of loading. Due to the heterogeneity of the time point of baseline measurements and contradictory findings in the studies, it is difficult to draw clear conclusions regarding the recession of the buccal mucosa. With respect to the assessment of esthetic outcomes and patient satisfaction, the data available remain inconclusive.

Conventional Versus Digital Impressions for "All-on-Four" Restorations

PURPOSE

This study aimed to evaluate the most accurate impression technique for "All on Four" restoration, comparing conventional (CIG) and digital impressions (DIG).

MATERIALS AND METHODS

Patients randomly selected for this study were required to be edentulous in at least one arch, presenting with severe posterior mandibular or maxillary atrophy. All patients underwent full-arch immediate-load rehabilitations, which were fixed to a total of four implants (two axial and two tilted). Following implant placement, patients were stratified into two groups. Conventional pick-up was carried out in the control group, and digital impressions were performed in the test group. Following prosthetic rehabilitation, patients underwent intraoral digital radiographs to check for the presence of voids at the bar-implant connection and to evaluate accuracy. Three-, 6-, and 12-month follow-up examinations were performed.

RESULTS

A total of 25 patients received immediately loaded "All-on-Four" prostheses (17 maxillary, 13 mandibular) supported by four implants (total 120 implants), of which five received both maxillary and mandibular prosthetic rehabilitation (three patients in CIG, two patients in DIG). No implant dropouts occurred, showing a survival rate of 100%. The digital impression procedure required significantly less time than the conventional procedure (P < .001).

CONCLUSION

Results demonstrate that it is possible to develop computer-aided design/computer-assisted manufacturing (CAD/CAM) cobalt-chromium full-arch rehabilitations with satisfactory accuracy using digital impression techniques.

Clinical efficacy of immediate implant loading protocols compared to conventional loading depending on the type of the restoration: a systematic review

BACKGROUND AND OBJECTIVES

Immediate loading has become a predictable option to restore all clinical situations. The aim of this systematic review was to assess whether immediate loading protocols achieve comparable clinical outcomes when compared to conventional loading protocols depending on the type of prosthetic restoration.

METHODS

A protocol was developed aimed to answer the following focused question: "What are the effects of immediate implant loading protocols compared to conventional implant loading, in terms of implant failure, marginal bone levels, and biological and mechanical complications based on the type of restoration?" The next subanalysis were performed as follows: the extent, type, and material of the restoration and the type of occlusal contact in function. This systematic review only included randomized controlled trials (RCTs) with a follow-up of at least 6 months after implant loading.

RESULTS

Thirty-seven final papers were included. The results from the meta-analyses have shown that the immediately loading implants demonstrated a statistically significant higher risk of implant failure [RR = 1.92; 95% CI (1.04; 3.54); P = 0.036], a statistically significant lower bone loss [WMD = 0.046; 95% CI (0.043; 0.049); P = 0.000] and a smaller increase in ISQ values [WMD = -1.096; 95% CI (-1.615; -0.577); P < 0.001, although both groups attained high survival rates (98.2% in the test and 99.6% in the control). Single teeth implants were greater risk of failure, when compared to immediately loaded full arch restorations (RR = 2 vs. 0.9), so as the occlusal pattern when compared to non-occlusal (RR = 1.9 vs. 1.4).

CONCLUSIONS

Immediate loading may impose a greater risk for implant failure when compared to conventional loading, although the survival rates were high for both groups.

Loading protocols for implant-supported overdentures in the edentulous jaw: a systematic review and meta-analysis

PURPOSE

High survival rates have frequently been reported for immediately loaded implants. The aim of this systematic review was to compare immediately loaded with early and conventional loaded implants for overdenture treatment with regard to their 1-year survival rates.

MATERIALS AND METHODS

Systematic database (Medline, Embase, CENTRAL) and hand searches were performed to identify prospective studies reporting on loading protocols for two-piece implants with micro-rough surfaces and diameters > 3 mm. Studies were grouped according to loading protocol, jaw, number of implants per jaw, and splinting. Meta-analyses of comparative reports were performed based on the calculated risk difference (RD). Descriptive analyses included the remainder prospective studies. Two investigators extracted the data independently. Kappa statistics served to evaluate the inter-investigator agreement.

RESULTS

Of the 3,142 identified articles, 58 were included for data extraction. They comprised 11 studies comparing loading protocols as well as a further 47 prospective reports. Comparative studies were only available for mandibular overdentures. The meta-analysis revealed a statistical tendency to support conventional over immediate loading (RD: -0.03, 95% confidence interval: -0.06, 0.00). The descriptive analysis of studies with lower evidence demonstrated partially contradictory findings. There, reported survival rates for immediately loaded implants lay between 81.6% and 100%, but depended on the number of implants placed. Most investigators preferred verifying an initial high insertion torque (≥ 35 Ncm) or ISQ value (≥ 60) before considering an implant for an immediate or early loading protocol.

CONCLUSIONS

Although all three loading protocols provide high survival rates, early and conventional loading protocols are still better documented than immediate loading and seem to result in fewer implant failures during the first year. Only a few prospective case series are available to document immediate loading of implants supporting an overdenture in the edentulous maxilla.

Immediate versus delayed loading of dental implants in edentulous patients' maxillae: a 6-year prospective study

PURPOSE

This study compared the surgical protocol efficacy of immediate and delayed implant loading in edentulous maxillae opposed by natural or restored mandibular dentitions over an observational period of 6 years or longer. The selected outcome determinants included individual implant survival data, progressive measurements of peri-implant bone resorption, prosthodontic survival and success data, and report of complications.

MATERIALS AND METHODS

A convenience sample of 49 patients requiring fixed implant-supported maxillary prostheses was split into two groups. The test group (34 patients) was treated according to the Columbus Bridge Protocol, which prescribes the insertion of four to six implants, including distally tilted implants, and load within 24 hours. The control group (15 patients) was treated via a two-stage surgical protocol of 6 to 9 straight implants that were loaded a mean 8.75 months after stage-one implant surgery. Two hundred sixty implants (test: n = 163, control: n = 97) were placed, and all subjects were ultimately treated with screw-retained full-arch prostheses.

RESULTS

Two patients dropped out (one in the test group and one in the control group) by the time of the scheduled sixth annual visit. The other patients were followed up for 75.2 months (range: 72 to 90 months). At the 6-year follow-up, no differences in implant cumulative survival rates were found between groups. Significantly less bone loss was found in the test group (mean: 1.62 mm) compared with the control group (mean: 2.44 mm). All of the original prostheses were maintained throughout the study's observation period and were functioning satisfactorily at each patient's last recall appointment.

CONCLUSION

Patients who received immediate and delayed implant loading in their edentulous maxillae demonstrated similar survival outcomes. However, less marginal bone loss was recorded around the immediately loaded implants over the study's 6-year follow-up period.

Maxillary sinus floor elevation with simultaneous implant placement without grafting materials: a systematic review and meta-analysis

The present study aimed to conduct a systematic review and meta-analysis on the effectiveness of maxillary sinus floor elevation and immediate implant installation without the use of grafting material. An electronic search without date or language restriction ​​was performed in PubMed/MEDLINE, Cochrane Central Register of Controlled Trials, Web of Science, Embase, and the grey literature, to May 2016. Eligibility criteria encompassed prospective and retrospective cohort studies, controlled clinical trials, and randomized clinical trials. The search and selection process yielded 18 studies, published between 2005 and 2016. A meta-analysis was conducted only for experimental studies comparing sinus floor elevation with and without grafting material; results were expressed as the standardized mean difference (SMD) or risk ratio (RR) with the 95% confidence interval (CI). An average gain in bone height of 4.7mm over an average 39.4 month period was observed in the sinus elevated without grafting material. Regarding implants, there was a cumulative average survival rate of 97%. On meta-analysis, bone gain (P=0.98) and implant survival (P=0.13) did not differ significantly between sinuses lifted with or without grafting material, with a SMD of 0.01 (95% CI -0.42 to 0.44) and with a RR of 0.55 (95% CI 0.26 to 1.19), respectively.

Marginal Bone Response Around Immediate- and Delayed-Loading Implants Supporting a Locator-Retained Mandibular Overdenture: A Randomized Controlled Study

PURPOSE

Implant-supported mandibular overdentures (OVDs) have been proposed as the gold standard for the treatment of edentulous mandibles. There is limited evidence on the clinical outcomes of immediate loading of two unsplinted implants supporting a mandibular OVD. The purpose of this randomized controlled trial was to evaluate the performance of two unsplinted implants supporting a Locator-retained mandibular OVD over 12 months loaded immediately or after a delay.

MATERIALS AND METHODS

Each patient received two implants 4.0 mm in diameter and 8 to 15 mm long. Locator-retained mandibular OVDs were connected to the implants either immediately (IL) or 3 months postsurgery (DL). The primary response variable was radiographic bone loss (RBL) at 6 and 12 months postsurgery. Implant length, insertion torque, implant failure, prevalence of maintenance visits, and prosthetic complications were also recorded.

RESULTS

Thirty participants (15 in the IL and 15 in the DL groups) were evaluated at 12 months. The implant cumulative survival rates were 100% and 93% for DL and IL, respectively. The mean RBL from baseline to 1 year was 0.54 (± 0.5) mm and 0.25 (± 0.5) mm for DL and IL, respectively. A statistically significant difference was observed at 12 months, with less RBL in the IL group. Insertion torque and implant length were not correlated with RBL. Also, no difference in frequency of maintenance visits and prosthetic complications was reported between the groups.

CONCLUSION

Immediate loading of two unsplinted implants supporting a Locator-retained mandibular OVD seems to be a suitable treatment option. Significantly less RBL was observed after 1 year of loading around IL implants than around DL implants. Furthermore, neither implant length nor insertion torque seemed to affect RBL 1 year after surgical placement.

Soft and Hard Tissue Changes Following Immediate Placement or Immediate Restoration of Single-Tooth Implants in the Esthetic Zone: A Systematic Review and Meta-Analysis

PURPOSE

This systematic review aimed to compare immediate protocols with conventional protocols of single-tooth implants in terms of changes in the surrounding hard and soft tissue in the esthetic area.

MATERIALS AND METHODS

Electronic and manual searches were performed in PubMed, EMBASE, Cochrane, and other data systems for research articles published between January 2001 and December 2014. Only randomized controlled trials (RCTs) reporting on hard and or soft tissue characteristics following a single-tooth implant were included. Based on the protocol used in each study, the included studies were categorized into three groups to assess the relationships between the factors and related esthetic indexes. Variables such as marginal bone level changes (mesial, distal, and mean bone level), peri-implant soft tissue changes (papilla level, midbuccal mucosa, and probing depth), and other esthetic indices were taken into consideration. The data were analyzed using RevMan version 5.3, Stata 12, and GRADEpro 3.6.1 software.

RESULTS

A total of 13 RCTs met the inclusion criteria. Four studies examined immediate implant placement, five studies examined immediate implant restoration, and four studies examined immediate loading. Comparing the bone level changes following immediate and conventional restoration, no significant differences were found in the bone level of the mesial site (standard mean difference [SMD] = -0.04 mm; 95% confidence interval [CI]: -0.25 to 0.17 mm), the distal site (SMD = -0.15 mm; 95% CI: -0.38 to 0.09 mm), and the mean bone level changes (SMD = 0.05 mm; 95% CI: -0.18 to 0.27 mm). The difference in the marginal bone level changes between immediate and conventional loading was also not statistically significant (SMD = -0.05 mm; 95% CI: -0.15 to 0.06 mm for the mesial site and SMD = -0.02 mm; 95% CI: -0.09 to 0.05 mm for the distal site). Soft tissue changes following immediate and conventional restoration reported no significant differences in the papillae level of the mesial site (SMD = 0.18 mm; 95% CI: -0.00 to 0.37 mm), the papillae level of the distal site (SMD = -0.12 mm; 95% CI: -0.34 to 0.09 mm), and the midbuccal mucosa (SMD = -0.22 mm; 95% CI: -1.29 to 0.85 mm).

CONCLUSION

Within the limitations, it can be concluded that immediately placed, restored, or loaded single-tooth implants in the esthetic zone result in similar hard and soft tissue changes compared with conventional protocols.

Immediate nonfunctional versus immediate functional loading and dental implant failure rates: a systematic review and meta-analysis

OBJECTIVES

The purpose of the present review was to test the null hypothesis of no difference in the implant failure rates, postoperative infection, and marginal bone loss for patients being rehabilitated using dental implants with immediate nonfunctional loading (INFL) compared to immediate functional loading (IFL), against the alternative hypothesis of a difference.

METHODS

An electronic search without time or language restrictions was undertaken in March 2014. Eligibility criteria included clinical human studies, either randomized or not. The estimates of relative effect were expressed in risk ratio (RR) and mean difference (MD) in millimeters.

RESULTS

1059 studies were identified and 11 studies were included, of which 7 were of high risk of bias, whereas four studies were of low risk of bias. The results showed that the procedure used (nonfunctional vs. functional) did not significantly affect the implant failure rates (P=0.70), with a RR of 0.87 (95% CI 0.44-1.75). The wide CI demonstrates uncertainty about the effect size. The analysis of postoperative infection was not possible due to lack of data. No apparent significant effects of non-occlusal loading on the marginal bone loss (MD 0.01mm, 95% CI -0.04-0.06; P=0.74) were observed.

CONCLUSIONS

The results of this study suggest that the differences in occlusal loading between INFL and IFL might not affect the survival of these dental implants and that there is no apparent significant effect on the marginal bone loss.

CLINICAL SIGNIFICANCE

There has been a controversy concerning whether dental implants should be subjected to immediate functional or nonfunctional loading. As the philosophies of treatment may alter over time, a periodic review of the different concepts is necessary to refine techniques and eliminate unnecessary procedures. This would form a basis for optimum treatment.

Implant loading protocols for partially edentulous patients with extended edentulous sites--a systematic review and meta-analysis

PURPOSE

The aim of this study was to systematically review the evidence for immediate implant loading in partially edentulous patients with extended edentulous sites and evaluate potential treatment modifiers.

MATERIALS AND METHODS

An electronic search was performed in Medline, Embase, and Central to identify studies investigating the outcome of implants subjected to immediate loading (IL) (less than 1 week), early loading (EL) (1 week to 2 months), or conventional loading (CL) (more than 2 months) with implant-supported fixed dental prostheses (IFDPs) in partially edentulous patients with extended edentulous sites, ie, at least two adjacent teeth are missing. Only human studies with at least 10 cases and a minimum follow-up time of 12 months, reporting on solid-screw-type implants with rough surfaces and a diameter of at least 3 mm, were included. Weighted means of implant survival rates and risk ratios for implant survival at 1 year using meta-analytic tools were calculated to perform the following comparisons: IL vs EL, IL vs CL, and IL in the maxilla vs mandible. Noncomparative studies reporting on IL and EL protocols were summarized through descriptive methods.

RESULTS

The search provided 3,872 titles, 837 abstracts, and 444 full-text articles. A total of 24 publications that comprised six comparative studies (five randomized controlled trials, one nonrandomized controlled trial) and 18 noncomparative studies were included for analysis. The comparison of weighted mean survival rates revealed no statistically significant difference between IL (97.9%) and EL (97.8%, P = .9405), and between IL (100%) and CL (99.3%, P = .3280). Meta-analysis showed no statistically significant difference in implant survival at 1 year between IL and EL (RR 0.90; 95% CI 0.30, 2.70; P = .502). A meta-analysis comparing IL and CL could not be performed due to the low number of failures. No statistically significant difference was found for IL implants placed in the maxilla vs the mandible (RR 1.55; 95% CI 0.49, 4.84; P > .05). Due to the small number of IL implants placed in the anterior, a comparison between implant survival in anterior vs posterior zones was not performed. Treatment modifiers were bone quality, primary stability, insertion torque, ISQ values, implant length, the need for substantial bone augmentation, the timing of implant placement, and the presence of parafunctional and smoking habits.

CONCLUSIONS

IL presents similar implant survival rates as EL or CL for partially edentulous patients with extended edentulous sites in the posterior zone, as long as strict inclusion/exclusion criteria are followed. There is a lack of evidence for IL of multiple implants in the anterior zone of partially edentulous patients. Preliminary evidence suggests that IL may be equally successful in either the maxilla or mandible. Further research is needed before IL in partially edentulous patients with extended edentulous sites can be recommended in everyday practice.

Accuracy of immediate dental implant placement with task-autonomous robotic system and navigation system: An in vitro study

OBJECTIVES

The aim of this study was to compare the accuracy of dental implant placement in a single tooth gap, including the postextraction site and healed site, using a task-autonomous robotic system and a dynamic navigation system.

MATERIALS AND METHODS

Forty partially edentulous models requiring both immediate and conventional implant placement were randomly divided into a robotic system group and a navigation system group. The coronal, apical, and angular deviations of the implants were measured and assessed between the groups.

RESULTS

The deviations in immediate implant placement were compared between the robotic system and dynamic navigation system groups, showing a mean (±SD) coronal deviation of 0.86 ± 0.36 versus 0.70 ± 0.21 mm (p = .101), a mean apical deviation of 0.77 ± 0.34 versus 0.95 ± 0.38 mm (p = .127), and a mean angular deviation of 1.94 ± 0.66° versus 3.44 ± 1.38° (p < .001). At the healed site, significantly smaller coronal deviation (0.46 ± 0.29 vs. 0.70 ± 0.30 mm, p = .005), apical deviation (0.56 ± 0.30 vs. 0.85 ± 0.25 mm, p < .001), and angular deviation (1.36 ± 0.54 vs. 1.80 ± 0.70 mm, p = .034) were found in the robotic system group than in the dynamic navigation group.

CONCLUSIONS

The position in both immediate and conventional implant placement was more precise with the task-autonomous robotic system than with the dynamic navigation system. Its performance in actual clinical applications should be confirmed in further trials.

Human Histologic Evidence of New Bone Formation and Osseointegration Between Root Dentin (Unplanned Socket-Shield) and Dental Implant: Case Report

The socket-shield technique described 7 years ago has since grown in its reporting in the literature as a valid method of ridge preservation at immediate implant placement. To date, large clinical cohorts with up-to-4-year follow-up have been reported. Additionally, evidence of tissue histology at the dental implant and socket-shield has been demonstrated in the animal model. However, human histologic evidence has not yet been available, and the clinician's uncertainty regarding the tissues that may form between the socket-shield and dental implant may remain unanswered until now. This case report presents the first human histologic evidence that bone may entirely fill the space between root dentin and an osseointegrated implant surface.

Immediate function on the day of surgery compared with a delayed implant loading process in the mandible: a randomized clinical trial over 5 years

OBJECTIVES

To appraise the feasibility of loading four implants with a pre-existing denture converted to a fixed dental prosthesis (FDP) on the day of implant surgery compared with waiting for 3- to 4-month healing.

METHODS

Patients with an edentulous, fully healed mandible were recruited in a faculty clinic to partake in a blinded two-arm parallel randomized controlled trial (RCT). The participants received four parallel intraforamina mandibular implants with a moderately rough titanium surface (Brånemark System Mk III or Mk IV TiUnite; Nobel Biocare AB, Göteborg, Sweden). The implants were loaded on the same day by converting the participants' pre-existing denture in the experimental group. The implants were placed using a one-stage surgery procedure, and the participants' pre-existing denture were soft-relined in the control group. For both groups, the permanent 10- to 12-unit FDP consisting of a type-3 cast precious alloy veneered with acrylic and artificial teeth was placed 3-4 months after implant surgery. All participants have been recalled annually for 5 years for appraisal of bone loss and registration of adverse events.

RESULTS

Thirty-five of the original 42 participants (83%) returned for clinical and radiological examinations at the 5-year follow-up recall. No selective dropout or specific reasons for dropout was identified in the two study arms; leaving n = 17 (Intention-to-treat group, ITT) in the experimental group, alternatively n = 13 as per protocol group (PP), and n = 18 participants in the control group (ITT = PP). At study commencement, five of the participants assigned to the experimental group did not receive their planned intervention. In the control group, one implant failed to osseointegrate and another failed due to bone loss after 5 years. The crestal bone level changes over 5 years were identical in the experimental and control groups, that is, 1.2 mm (SD = 0.7). There were no differences between the two study arms with regard to incidence of biological and technical adverse events.

CONCLUSIONS

Implants in the anterior mandible loaded immediately with a converted pre-existing denture appear to yield analogous clinical outcomes compared with waiting for 3-4 months over the first 5 years following implant surgery.

Full Arch Implant-Prosthetic Rehabilitation in Patients with Type I Diabetes Mellitus: Retrospective Clinical Study with 10 Year Follow-Up

The aim of this retrospective clinical study was to evaluate and compare implant survival, marginal bone loss, and clinical and prosthetic complications in healthy patients and patients with type I diabetes undergoing full arch implant-prosthetic rehabilitation. A total of 47 patients needing total fixed rehabilitation of one or both arches were enrolled for this study. Based on the absence of any systemic diseases (Group A) or the presence of type I diabetes (Group B), the sample was divided into two groups. According to the grade of bone atrophy in the posterior region, patients received full arch rehabilitation (of one or both jaws) with 6 axial implants or, if the residual posterior bone height was insufficient, All-on-Four rehabilitation and a total 236 dental implants were placed. Follow-up visits were performed 1 week after surgery, at 3 and 6 months and then once a year for the next 10 years. No statistically significant differences between groups were recorded about implant survival rates, marginal bone loss, or clinical and prosthetic complications. However, concerning complications, post-surgical bleeding and wound infection were recorded in Group A more than in Group B. In cases of compensated diabetes compensation, implant placement could be considered a safe procedure.

Marginal bone loss evaluation around immediate non-occlusal microthreaded implants placed in fresh extraction sockets in the maxilla: a 3-year study

OBJECTIVE

To evaluate marginal bone loss over 3 years around immediate microthreaded implants placed in the maxillary anterior/esthetic zone and immediately restored with single crowns.

MATERIAL AND METHODS

Seventy-one implants (with microthreads up to the platform--rough surface body and neck, internal connection and platform switching) were placed in fresh extraction sockets in the maxillary arches of 30 men and 23 women (mean age 37.85 ± 7.09 years, range 27-60). All subjects had at least 3 mm of soft tissue to allow the establishment of adequate biologic width and to reduce bone resorption. Each patient received a provisional restoration immediately after implant placement with slight occlusal contact. Mesial and distal bone height was evaluated using digital radiography on the day following implant placement (baseline) and after 1, 2, and 3 years. Primary stability was measured with resonance frequency analysis.

RESULTS

No implants failed, resulting in a cumulative survival rate of 100% after 3 years. Marginal bone loss from implant collar to bone crest measured at baseline (peri-implant bone defect at the fresh extraction socket) and after 3 years was 0.86 mm ± 0.29 mm. Mesial and distal site crestal bone loss ranged from 3.42 mm ± 1.2 mm at baseline to 3.51 mm ± 1.5 mm after 3 years (P = 0.063) and from 3.38 mm ± 0.9 mm at baseline to 3.49 mm ± 0.9 mm after 3 years, respectively (P = 0.086).

CONCLUSIONS

This prospective study found minimal marginal bone loss and a 100% implant survival rate over the 3-year follow-up for microthreaded immediate implants subjected to immediate non-occlusal loading.

Comparative study of immediate loading on short dental implants and conventional dental implants in the posterior mandible: A randomized clinical trial

PURPOSE

Immediate dental implant loading has been investigated with favorable results. However, short implants have not been investigated in this treatment option. This study compared the clinical outcomes and survival rates of immediately loaded short and conventional length dental implants in replacing mandibular molar teeth.

MATERIALS AND METHODS

Forty-six implants (23 short dental implants and 23 conventional dental implants) in 46 patients were included in the study. Provisional computer-aided design/computer-aided manufacturing (CAD/CAM) ceramic crowns were cemented to the abutments and immediately loaded. Several clinical parameters were recorded and statistically analyzed at 4-month- and 1-year-follow-up.

RESULTS

Two short implants lost integration, and one conventional implant failed. No statistically significant difference between the two implant types was found (P = 1.00). Minor complications were recorded; three provisional crown fractures were found in the short implant group and two provisional crown fractures in the conventional implant group. There was no significant difference in implant stability quotient values for short or conventional implants between baseline (short: 73.86 ± 2.38, conventional: 75.05 ± 3.26, P = .088), 4 months after loading (short: 72.37 ± 1.35, conventional: 72.89 ± 1.87, P = .165), and 1 year after loading (short: 74.60 ± 2.03, conventional: 75.35 ± 2.66, P = .296). The mean marginal bone level loss 4 months after loading was 0.28 ± 0.29 mm for short implants and 0.25 ± 0.25 mm for conventional implants (P = .73), and at 1 year after loading was 0.33 ± 0.47 mm for short implants and 0.26 ± 0.27 mm for conventional implants (P = .554); there was no statistical difference between the two implant types.

CONCLUSION

The immediate loading of short implants is comparable to conventional length implants in terms of implant survival, marginal bone level change, and implant stability quotient value.

New-design dental implants: a 1-year prospective clinical study of 344 consecutively placed implants comparing immediate loading versus delayed loading and flapless versus full-thickness flap

PURPOSE

This study compared the 1-year success rates of immediately loaded dental implants to delayed loaded implants, regardless of the surgical technique (flapless or conventional full-thickness flap) and regardless of extraction time. It also examined whether the surgical technique had an influence on the success rate of the immediately loaded implants.

MATERIALS AND METHODS

A total of 344 dental implants, some with a new expanded winged-thread design, were placed in 155 patients; 53% of the implants were immediately loaded. Of the immediately loaded implants, 68.9% were placed with a flapless surgical technique and 88% were placed in extraction sites. Pocket depth, mobility, bleeding on probing, presence of erythema, pain, or radiolucency around the implants, as well as clinical findings, were recorded. Implants were followed from placement through definitive restoration. Descriptive, univariate, and multivariate analyses using clustered marginal approach of the Cox proportional hazards model were applied.

RESULTS

Of the 344 implants in the study, 10 (2.9%) failures were recorded, 7 of which were immediately loaded; however, there was no significant difference in failure rates between the immediate and delayed loading groups. Seven of the implants that failed were placed with a flapless (extraction site) technique; however, there was no significant difference in the failure rates between the flapless versus full-thickness flap technique in immediately loaded implants.

CONCLUSIONS

The clinical success of immediately loaded implants after 1 year showed no difference from the success rate of delayed loaded implants. The implantation procedure (flapless versus conventional flap) or extraction time also had no influence on the success rate of the immediately loaded implants.

Clinical Outcome After 8 to 10 Years of Immediately Restored Single Implants Placed in Extraction Sockets and Healed Ridges

Recent systematic reviews point to the scarcity of single implants followed up longer than 5 years, and the incidence of biologic/technical complications is underreported. This prospective follow-up study documents 8- to 10-year clinical outcomes of immediately restored single implants in extraction sockets (immediate implant treatment [IIT]) and healed bone (conventional implant treatment [CIT]). Patients received a single, chemically modified, moderately rough titanium implant and a provisional crown on the day of surgery in the anterior maxilla (second premolar to second premolar). Provisional crowns were replaced by permanent crowns after 10 weeks. Implant survival, complications, crestal bone changes, plaque score, probing depth, and bleeding on probing were regularly recorded up to 10 years of follow-up. Of 16 patients who underwent IIT, 11 could be evaluated after 8 years. Of the 23 patients who received an implant in healed bone, 18 were finally evaluated. One implant failed in the IIT group at 12 weeks; all implants survived in the CIT group; 38% of the patients experienced at least one complication; 10% had one or more biologic complications, whereas 31% experienced one or more technical complications. There were no significant changes in crestal bone level from 1 to ≥ 8 years of follow-up for either group or between IIT and CIT at any time point (P ≥ .129). Only 6.9% (2 of 29) implants demonstrated progressive bone loss > 2 mm combined with pockets ≥ 6 mm. Immediately restored single implants in extraction sockets and healed ridges demonstrate good long-term outcomes in terms of implant survival, crestal bone loss, and peri-implant health. However, biologic and especially technical complications are common.