Immediate provisionalization of dental implants placed in healed alveolar ridges and extraction sockets: a 5-year prospective evaluation

The influence of connective tissue grafting on the reconstruction of a missing facial bone wall using immediate implant placement and simultaneous bone reconstruction: a retrospective long-term cohort study

PURPOSE

This retrospective cohort study evaluates the influence of connective tissue grafts (CTG) on bone regeneration at implant sites with total loss of the buccal bone wall treated with flapless immediate implant placement (IIP) and reconstruction with autogenous bone chips (AB) within a follow-up of up to 13 years.

METHODS

Sixty implants were inserted in 55 patients in sites with total loss of the buccal bone wall between 2008 and 2021. The implants were inserted and the buccal gaps were grafted by AB. A subgroup of 34 sites was grafted additionally with CTG using tunnel technique. Primary outcome was the vertical bone regeneration in height and thickness. Secondary outcome parameters were interproximal marginal bone level, recession, soft tissue esthetics (PES), width of keratinized mucosa (KMW) and probing depths (PPD).

RESULTS

Mean follow-up period was 60.8 months. In 55 sites a complete vertical bone regeneration was documented. The mean buccal bone level increased by 10.6 mm significantly. The thickness of the buccal bone wall ranged between 1.7 and 1.9 mm, and was significantly thicker in sites without CTG. Interproximal marginal bone level was at implant shoulder level. The mean recession improved significantly by 1.2 mm. In sites with CTG, recessions and PES improved significantly more.

CONCLUSIONS

Additional CTG in extraction sites with total buccal bone loss followed by IIP with simultaneous AB grafting led to improved PES and recession, but also to a thinner buccal bone wall compared to sites grafted just with AB.

Early Implant Placement with Immediate Loading in the Mandibular Anterior Region: A Rapid Solution to Edentulism

The aim of this article is to present the case of an early implant placement with immediate loading in the mandibular anterior region as a rapid solution to edentulism. A 40-year-old healthy male patient reported with a chief complaint of loosening of tooth in the lower front region of the jaw. On intraoral examination, there was a mobile tooth with respect to 41. The mobile tooth was extracted, and early implant placement was done along with Bio-Oss bone grafts to fill the jumping distance with no barrier membrane. Immediate provisionalisation was done on early-placed dental implants. After 5 months of the healing period, the final implant-level impressions were made, and the provisional crown was replaced with the final zirconia crown. This case report demonstrates satisfactory esthetic and functional outcomes along with various other advantages.

Clinical performance of immediately placed and immediately loaded single implants in the esthetic zone: A systematic review and meta-analysis

OBJECTIVES

The aim of this study was to assess the following PIO question: In adult patients treated with an indication for single tooth extraction in the maxillary esthetic zone (15-25), what is the influence of an immediate implant placement and immediate loading protocol on the clinical performance (primary aim) and esthetic outcomes (secondary aim) focusing on investigations published after 2010.

MATERIAL AND METHODS

An electronic search in Medline (PubMed), the Cochrane Central Register of Controlled Trials, and EMBASE databases up to April 2022 was performed to identify clinical studies investigating the outcome of single implants subjected to immediate placement with immediate restoration/loading (Type 1A).

RESULTS

Sixty-three studies (10 randomized controlled trials, 28 prospective and 25 retrospective cohort studies) were included with a follow-up ranging from 12 to 96 months. One thousand nine hundred sixty-one implants reported survival rates of 99.2 (98.6-99.5) % at 1 year, 97.5 (95.9-98.4) % after 3 years, and 95.8 (93.3-97.4) % after 5 years; 1064 immediately loaded restorations presented survival rates of 98.9 (97.8-99.5) % after 1 year, 96.8 (93.6-98.4) % after 2 years, and 94.8 (89.6-97.4) % after 5 years. Comparing baseline to 12-month data using the Hedges' g effect size (95% CI), papilla height presented an overall effect size of -0.71 (-1.25, -0.1) mm, midfacial recession change of -0.15 (-0.66, 0.36) mm, and a 0.82 (0.37, 1.28) gain in PES.

CONCLUSIONS

Immediate implant placement and immediate loading can be considered a predictable and safe treatment option for single maxillary anterior restorations with adequate survival rates and favorable esthetics outcomes for up to 5 years.

Selection criteria for immediate implant placement and immediate loading for single tooth replacement in the maxillary esthetic zone: A systematic review and meta-analysis

OBJECTIVES

The aim of this study was to review available evidence for Type 1A (immediate implant placement and immediate loading) of single tooth replacement in the maxillary esthetic zone.

MATERIALS AND METHODS

An electronic search was conducted utilizing the databases of MEDLINE, Embase, and Cochrane to identify publications reporting on the outcomes of Type 1A for single tooth replacement in the maxillary esthetic zone. The success and survival rates of the included articles were reported, which were further categorized according to the clinical criteria reported in Type 1A. Mean survival rates were univariately compared between risk groups and additionally between studies published before and since 2012 using bias-corrected and study size-weighed bootstrap tests. A study time-correcting meta-analysis was then performed to obtain an overall effect for the study pool.

RESULTS

A total of 3118 publications were identified in the search, with a total of 68 articles included. A mean number of implants per study were 37.2 and mean follow-up was 2.8 years. All the included studies utilizing Type 1A report highly selective inclusion and exclusion criteria. Univariate risk group comparison determined that studies before 2012 report a significantly lower mean survival rate (difference of -1.9 percentage points [PP], 95% CI: [-0.3, -4.0], p = .02), facial gap dimension had an impact on survival rates (+3.1 PP [0.2, 5.3] for width >2 mm, p = .04), as well as presence of endodontic infection (+2.6 PP [0.9, 5.1], p = .004).

CONCLUSIONS

Type 1A has a high survival rate in studies reporting strict patient and site selection criteria. Further research is required to assess esthetic and functional success with Type 1A treatments.

Patient-specific 3D printed models for enhanced learning of immediate implant procedures and provisionalization

INTRODUCTION

This study aimed to describe the fabrication, implementation and evaluation of 3D-printed patient-specific models for unskilled students to enhance learning in immediate implant procedures and provisionalization.

MATERIALS AND METHODS

The individualized simulation models were designed and processed based on CT and digital intraoral scanning of a patient. Thirty students performed simulation implant surgery and provisionalized the implant sites on the models and answered questionnaires to assess their perceptions before and after the training. The scores of the questionnaires were analysed using the Wilcoxon signed-rank test.

RESULTS

Significant differences before and after training were found in the students' responses. Students reported better results in understanding of surgical procedures, knowledge in prosthetically driven implantology, understanding of minimally invasive tooth extraction, confirming the accuracy of surgical template, usage of the guide rings and usage of the surgical cassette after simulation training. The overall expenditure on the simulation training involving 30 students amounted to 342.5 USD.

CONCLUSIONS

The patient-specific and cost-efficient 3D printed models are helpful for students to improve theoretical knowledge and practical skills. Such individualized simulation models have promising application prospects.

Marginal Bone Level and Biomechanical Behavior of Titanium-Indexed Abutment Base of Conical Connection Used for Single Ceramic Crowns on Morse-Taper Implant: A Clinical Retrospective Study

The goal of this retrospective clinical study was to evaluate the behavior of Morse-taper indexed abutments by analyzing the marginal bone level (MBL) after at least 12 months of function. Patients rehabilitated with single ceramic crowns between May 2015 and December 2020 received single Morse-taper connection implants (DuoCone implant) with two-piece straight abutment baseT used for at least 12 months, presenting periapical radiograph immediately after crown installation were enrolled. The position of the rehabilitated tooth and arch (maxilla or mandible), crown installation period, implant dimensions, abutment transmucosal height, installation site (immediate implant placement or healed area), associated with bone regeneration, immediate provisionalization, and complications after installation of the final crown were analyzed. The initial and final MBL was evaluated by comparing the initial and final X-rays. The level of significance was α = 0.05. Seventy-five patients (49 women and 26 men) enrolled had a mean period of evaluation of 22.7 ± 6.2 months. Thirty-one implant-abutment (IA) sets had between 12–18 months, 34 between 19–24 months, and 44 between 25–33 months. Only one patient failed due to an abutment fracture after 25 months of function. Fifty-eight implants were placed in the maxilla (53.2%) and 51 in the mandible (46.8%). Seventy-four implants were installed in healed sites (67.9%), and 35 were in fresh socket sites (32.1%). Thirty-two out of these 35 implants placed in fresh sockets had the gap filled with bone graft particles. Twenty-six implants received immediate provisionalization. The average MBL was −0.67 ± 0.65 mm in mesial and −0.70 ± 0.63 mm in distal (p = 0.5072). The most important finding was the statistically significant difference comparing the values obtained for MBL between the abutments with different transmucosal height portions, which were better for abutments with heights greater than 2.5 mm. Regarding the abutments’ diameter, 58 had 3.5 mm (53.2%) and 51 had 4.5 mm (46.8%). There was no statistical difference between them, with the following means and standard deviation, respectively, −0.57 ± 0.53 mm (mesial) and −0.66 ± 0.50 mm (distal), and −0.78 ± 0.75 mm (mesial) and −0.746 ± 0.76 mm (distal). Regarding the implant dimensions, 24 implants were 3.5 mm (22%), and 85 implants (78%) had 4.0 mm. In length, 51 implants had 9 mm (46.8%), 25 had 11 mm (22.9%), and 33 implants were 13 mm (30.3%). There was no statistical difference between the abutment diameters (p > 0.05). Within the limitations of this study, it was possible to conclude that better behavior and lesser marginal bone loss were observed when using abutment heights greater than 2.5 mm of transmucosal portion and when placed implants with 13 mm length. Furthermore, this type of abutment showed a little incidence of failures within the period analyzed in our study.

Buccal soft tissue dehiscence defects at dental implants-associated factors and frequency of occurrence: A systematic review and meta-analysis

AIM

To identify the factors associated with buccal peri-implant soft tissue dehiscences (BSTDs) and their frequency of occurrence.

MATERIALS AND METHODS

Randomized controlled trials, controlled clinical trials, cohort studies, and case series assessing the frequency of occurrence of BSTD were included. BSTD was defined as an apical migration of the peri-implant soft tissues of ≥1 mm from the baseline examination (final restoration) or in comparison with the adjacent or contralateral natural tooth. Frequency distributions of BSTD related to the presence or absence of any surgical, prosthetic, or anatomic factor that may have contributed to the development of BSTD were recorded. Random-effects meta-analyses using odds ratios (OR) were performed to investigate the association of certain factors with the development of BSTD.

RESULTS

Twenty-four articles were finally included belonging to 22 clinical investigations. Patients at higher risk of developing BSTD were associated with thin biotype (OR = 2.85 [1.40, 5.8], n = 5, p = .003) and with buccally placed implants (OR = 14.37 [4.58, 45.14], n = 3, p ≤ .001). Patients without connective tissue grafting (CTG) had greater odds of developing BSTD (OR = 9.00 [3.11, 26.02], n = 5, p ≤ .001), while buccal bone plate thickness of <1 mm and immediately placed implants were not associated with greater BSTD (OR = 1.29 [0.35, 4.77], n = 2, p = .704 and OR = 1.56 [0.46, 5.26], n = 4, p = .477, respectively). The frequency of occurrence of BSTD varied across the included studies with a range from 0% to 61%.

CONCLUSIONS

Thin tissue biotype and buccally placed implants were associated with BSTD, whereas CTG seemed to have a protective effect. Thin buccal plates and immediately placed implants did not demonstrate a higher risk of BSTD.

Connective tissue graft vs porcine collagen matrix after immediate implant placement in esthetic area: A randomized clinical trial

BACKGROUND

The use of connective tissue graft (CTG) with immediate implant placement and provisionalisation have shown promising results. It is not clear if the same outcome could be achieved using porcine-derived collagen matrix (PDCM) as grafting material.

OBJECTIVES

This study aimed to assess the esthetic and functional outcomes of immediate temporization of immediately placed fully tapered implants combined with bone and soft tissue augmentation, using either a CTG or a PDCM, in fresh extraction sockets of the anterior sites.

MATERIALS AND METHODS

Patients with a failing anterior tooth were included in this study. After extraction, they received an immediate implant with simultaneous hard and soft tissue augmentation and immediate provisional restoration. Patients were randomly assigned to one of the group. Soft tissue augmentation in the control group (CTG) consisted of a CTG, whereas PDCM was used in the test group. After 4 months, definitive restorations were delivered, and pink esthetic score (PES) was evaluated at T1, prosthetic delivery, and at 12-month follow-up (T2). In addition, crestal bone change, probing depth, bleeding on probing, plaque index, bleeding on provisional removal, and implant stability quotient were also recorded.

RESULTS

A total of 45 patients received the intended treatment (22 controls and 23 tests) 45 implants totally, with no implant failures at T2. PES mean ± SD after 1 year was noted to be 12.9 ± 1.2 for the CTG group and 12.1 ± 1.3 for the PDCM group (p = 0.507).

CONCLUSION

Within the limits of this trial, both treatment protocols resulted in comparable esthetic outcomes, with results showing PES >12 and stable clinical parameters after 1 year of follow-up.

Immediate implant placement vs. early implant treatment in the esthetic area. A 1-year randomized clinical trial

OBJECTIVES

To assess the impact of implant placement and temporization timing on esthetic outcomes of single maxillary anterior implants with intact bone walls and interproximal bone.

MATERIALS AND METHODS

Test group patients received an immediate implant with immediate provisional restoration and socket preservation, while patients in the control group received an early implant placement with guided bone regeneration and delayed loading. Patients were followed for 1 year after final prosthetic and pink esthetic score (PES), mid-buccal mucosal level (MBML), crestal bone changes (CBC), and peri-implant soft tissue parameters, and patient chair time was recorded.

RESULTS

Fifty patients received the intended treatment (25 test and 25 control). No implants failed. PES after 1 year was 12.8 ± 1.19 for the test group and 12.5 ± 1.36 for the control group (p = .362). MBML difference between baseline (after final crown delivery) and the 1-year follow-up was gain of 0.2 ± 1.02 mm for the test group (p = .047) and no change in the control group. CBC after 1 year were 0.1 mm ± 0.21 mm (mesial) and 0.2 mm ± 0.22 mm (distal) for the test group and 0.2 mm ± 0.25 mm (mesial) and 0.3 mm ± 0.19 mm (distal) for the control group, p = .540 (mesial) and p = .462 (distal). Test group required half the chair time (127 ± 13 min) when compared to the control group (259 ± 15 min, p < .001).

CONCLUSIONS

Within the limits of this trial, both treatment protocols resulted in excellent esthetic outcomes with PES >12 after 1-year follow-up.

Esthetic complications in implant dentistry

Esthetic complications in implant dentistry have become a significant consideration for patients and practitioners. This review presents an appraisal on the current knowledge of the physiological peri-implant soft-tissue dimensions and factors that may compromise peri-implant tissue esthetics. Factors such as papilla fill adjacent to the implant and midfacial mucosal height are critical parameters that determine the esthetic success of implant-supported restorations. Papilla fill adjacent to a single dental implant appears to depend upon the clinical attachment level of the neighboring tooth. A horizontal inter-implant distance of at least 3 mm is necessary to ensure optimal interproximal mucosal embrasure between two adjacent implants in the anterior maxilla. In cases where implants cannot be placed at least 3 mm apart, a single implant with a cantilever bridge should be considered. Buccolingual implant positioning plays a major role in midfacial mucosal height. Soft-tissue volume grafting following immediate implant placement in the presence of a thin soft-tissue phenotype or simultaneous to surgical peri-implantitis therapy might help to overcome facial mucosa recession.

Dental Implants Inserted in Fresh Extraction Sockets versus Healed Sites: A Systematic Review and Meta-Analysis

The present review aimed to evaluate the difference of dental implant failure rates and marginal bone loss (MBL) between implants inserted in fresh extraction sockets or healed sites. Electronic search was undertaken in three databases, plus manual search of journals, including studies randomized or not. Meta-analyses were performed besides meta-regressions, in order to verify how the odds ratio (OR) and MBL were associated with follow-up time. The review included 163 publications. Altogether, there were 17,278 and 38,738 implants placed in fresh extraction sockets and healed sites, respectively. Pairwise meta-analyses showed that implants in sockets had a higher failure risk in comparison to healed sites: OR 1.349, all studies included; OR 2.070, only prospective non-RCTs; OR 2.487, only RCTs (all p < 0.001). The difference in implant failure between the groups was statistically significant in the maxilla (OR 1.616, p = 0.029), but not in the mandible (OR 2.192, p = 0.075). The MBL mean difference (MD) between the groups was −0.053 mm (p = 0.089). There was an estimated decrease of 0.003 in OR (p = 0.284) and an increase of 0.006 mm (p = 0.036) in the MBL MD between groups for every additional month of follow-up. In conclusion, implants placed in fresh extraction sockets present higher risk of failure than implants placed in healed sites.

An open, randomised, multi-centre study, comparing straight and tapered apex implants design, in partially and totally edentulous maxillae

The design of the commercially available implant OsseoSpeed^® (control) was changed to a tapered apex with a smaller apical diameter; OsseoSpeed^® TX (test).

OBJECTIVE

The present study evaluated the clinical outcome of marginal bone level as primary outcome, and cumulative implant survival rate, primary stability and condition of the peri-implant mucosa as secondary outcomes, one year after loading.

MATERIAL AND METHODS

92 subjects (150 implants, ten centres), with partially or totally edentate maxillae were randomized to receive either test or control implants. One to six implants were placed in each subject using a one-stage surgical procedure. Subjects received a permanent prosthesis 10-12 weeks after implant placement and were followed for one year.

RESULTS

47 subjects in the test group received 82 implants and 45 subjects in the control group received 68 implants. Marginal bone level alterations from loading to 1-year follow-up was -0.02 × 0.41 mm (mean × SD) and -0.03 × 0.38 mm (mean × SD) for the test and the control group, respectively, indicating no difference between the groups. Non-inferiority was declared as confidence interval for the difference between control and test implants was no worse than 0.5 mm. The CSR was 98.8% in the test group and 100% in the control group, with no statistically significant difference between the groups.

CONCLUSIONS

Change of the apical design of a commercially available implant showed no significant effect on marginal bone level and CSR compared to the control implant. Missing data and many investigators may have influenced on the result. Trial registration number: NCT01324778.

The effect of implant-abutment connections on peri-implant bone levels around single implants in the aesthetic zone: A systematic review and a meta-analysis

Objective

To systematically review literature about the effect of different implant‐abutment interface designs on peri‐implant bone level changes, implant loss and mid‐buccal mucosa changes around single implants in the anterior maxilla. Reviewing three connection configurations: Platform switched conical (PS‐conical); Platform switched parallel (PS‐parallel); Platform matched parallel (PM‐parallel).

Methods

A detailed search was carried out in Pubmed, EMBASE, Cochrane, Scopus, Open Gray and African journals Online (until December 1, 2020) and was restricted to clinical prospective studies of at least 1 year and with at least 10 human participants. A meta regression analysis was carried out primarily on the pooled peri‐implant bone level changes followed by implant loss and mid‐buccal mucosa level change. Risk of bias was assessed with RoB 2.0 and ROBINS‐I. The manuscript complied with the PRISMA guidelines and was registered in the PROSPERO database (ID: 225092).

Results

A total of 5513 hits gave 44 eligible articles for the analyses. Bone level change did not differ significantly between the two platform switched connections; their bone loss scores were significantly lower than PM‐connection. The PS‐conical connections have significantly lower implant losses than the PM connection. Mid‐buccal mucosa level change was comparable between the three connection configurations. Moderate to high risk of bias was detected in the included studies.

Conclusions

The performance of PS‐conical and PS‐parallel connection configurations both favored bone loss scores compared to the PM‐parallel connection configuration. All three demonstrated mid‐buccal mucosa changes that were small and did not differ significantly amongst the groups.

Clinical and esthetic outcomes of immediate implant placement compared to alveolar ridge preservation: a systematic review and meta-analysis

AIM

The aim of this systematic review was to evaluate the efficacy of immediate implant placement (IIP) compared to implants placed after alveolar ridge preservation (ARP) in terms of clinical, esthetic, and patient-reported outcomes.

METHODS

A manual and electronic search (National Library of Medicine) was performed for controlled clinical trials, with at least 12 months of follow-up. Primary outcome variable was implant survival and secondary outcomes were marginal bone level (MBL) (change), pink esthetic score (PES), mid-facial mucosal level (change), papilla index score, complications, and patient-reported outcomes.

RESULTS

A total of 10 publications were included (7 randomized clinical trials and 3 controlled clinical trials). The results from the meta-analyses showed that survival rate was significantly lower in the IIP group compared to ARP group [RR = 0.33; 95% CI (0.14; 0.78); p = 0.01]. No significant differences between the two groups were observed regarding radiographic MBL, PES scores, or mid-facial mucosal level (p > 0.05).

CONCLUSION

The results from this systematic review and meta-analysis showed that IIP had lower survival rates and similar esthetic results when compared to ARP.

CLINICAL RELEVANCE

Clinicians should weigh the benefits and disadvantages of each intervention to select the optimal timing of implant placement.

Short communication: Cemented implant reconstructions are associated with less marginal bone loss than screw-retained reconstructions at 3 and 5 years of loading

OBJECTIVES

To analyse whether there is a difference in marginal bone levels (MBL) and the respective changes between cemented and screw-retained reconstructions at 3 and 5 years of loading.

METHODS

Radiographic data from 14 prospective multicentre clinical trials following implant loading with fixed cemented (CEM) or screw-retained (SCREW) reconstructions with a 3- to 5-year follow-up were retrieved from a database. MBL and MBL changes were assessed at initiation of implant loading (BL), at 3 (FU-3) and 5 years (FU-5) thereafter. The presence of peri-implantitis was also determined.

RESULTS

Data from 1,672 implants at BL, 1,565 implants at FU-3 and 1,109 implants at FU-5 were available. The mean MBL amounted to 0.57 mm (SD 0.87) at BL, 0.55 mm (SD 0.86) at FU-3 and 0.65 mm (SD 1.18) at FU-5. At FU-3, the mean MBL was 0.44 mm (SD 0.65) in group CEM and 0.63 mm (SD 0.99) in group SCREW showing a significant difference between the groups (intergroup <0.05). At FU-5, the mean MBL was 0.42 mm (SD 0.77) in CEM and 0.80 mm (SD 1.37) in SCREW, again with significant differences between both groups (p < .05). MBL changes between BL and FU-3 amounted to 0.11 mm (SD 1.02) (bone loss) in SCREW and -0.17 mm (SD 1.03) (bone gain) in CEM. Similarly, mean MBL changes from BL to FU-5 amounted to 0.23 mm (SD 1.31) (bone loss) in SCREW and -0.26 mm (SD 1.27) (bone gain) in CEM. The prevalence of peri-implantitis amounted to 6.9% in CEM and 5.6% in group SCREW (intergroup p = .29063) at FU-3. At FU-5, peri-implantitis amounted to 4.6% in CEM and 6.2% in group SCREW (intergroup p = .28242).

CONCLUSION

Cemented implant reconstructions compared with screw-retained reconstructions revealed higher marginal bone levels and similar rates of peri-implantitis during 5 years. The difference in MBL and the respective changes between the two groups, however, appear to be clinically negligible.

Could implant position influence the peri-implant parameters in edentulous mandibles of diabetics rehabilitated with overdentures? A split-mouth randomized study

This randomized controlled trial assessed the impact of crestal level position of implants installed in type 2 diabetes mellitus (T2DM) patients rehabilitated with overdentures. Twenty-two mandibular edentulous T2DM patients were submitted to implant placement for retention of an overdenture. By means of a split-mouth design, two implants were installed: one at supracrestal level (SL) and one at crestal level (CL). Clinical, immunoenzymatic and tomographic analyses were performed at prosthesis placement (baseline) and after 6, 12 and 24 months following implant loading. Increased peri-implant probing depths were detected in CL implants when compared with SL implants at all time-points (baseline P=0.047; 6 months P=0.014; 12 months P=0.027; 24 months P=0.036). Indeed, augmented clinical attachment levels were also detected in CL implants when compared with SL implants at all time-points (baseline P=003; 6 months P=0.045; 12 months P=0.029; 24 months P=0.026). CL implants demonstrated increased amounts of interleukin-6 (IL-6) at 6 months (P=0.043) and higher IL-17 (P=0.021), IL-21 (P=0.034) and tumour necrosis factor alpha (TNF-α) concentrations (P=0.030) at 24 months in comparison with SL implants. CL group revealed enhanced bone loss from baseline to 6 (P=0.032), 12 (P=0.043) and 24 months (P=0.028) when compared with SL. In conclusion, this study showed that implants placed supracrestally in T2DM patients rehabilitated with overdentures demonstrated lower bone loss and better clinical parameters with beneficial modulation of peri-implant immunoinflammatory biomarkers when compared with implants positioned at crestal level.

Immediate placement of single implants with or without immediate provisionalization in the maxillary aesthetic region: A 5-year comparative study

Aim

To compare marginal bone level changes around immediately placed and immediately provisionalized implants with immediately placed and delayed provisionalized implants in the aesthetic region after five years of function.

Materials and Methods

Forty patients with a failing tooth in the maxillary anterior region were randomly assigned immediate implant placement with immediate (Group A: n = 20) or delayed (Group B: n = 20) provisionalization. Definitive crown placement occurred three months after provisionalization. The primary outcomes were changes in marginal bone level. In addition, survival rates, buccal bone thickness, soft peri‐implant tissues, aesthetics and patient‐reported outcomes were assessed.

Results

After 5 years, the mean mesial and distal marginal bone level changes were 0.71 ± 0.68 mm and 0.71 ± 0.71 mm, respectively, in group A and 0.49 ± 0.52 mm and 0.54 ± 0.64 mm, respectively, in group B; the difference between the groups was not significant (p = .305 and p = .477, respectively). Implant and restoration survivals were 100%. No clinically relevant differences in buccal bone thickness or in mid‐facial peri‐implant mucosal level, aesthetic and patient outcomes were observed.

Conclusions

The mean marginal bone level changes following immediate implant placement and provisionalization were comparable with immediate implant placement and delayed provisionalization. (www.isrctn.com: ISRCTN57251089 and www.trialregister.nl: NL8255).

The Long-Term Effect of Smoking on 10 Years' Survival and Success of Dental Implants: A Prospective Analysis of 453 Implants in a Non-University Setting

Background: The purpose of this study was to compare the survival and peri-implant bone loss of implants with a fluoride-modified surface in smokers and non-smokers. Material and Methods: All patients referred for implant treatment between November 2004 and 2007 were scrutinized. All implants were placed by the same surgeon (B.C.). The single inclusion criterion was a follow-up time of at least 10 years. Implant survival, health, and bone loss were evaluated by an external calibrated examiner (S.W.) during recall visits. Radiographs taken at recall visits were compared with the post-surgical ones. Implant success was based on two arbitrarily chosen success criteria for bone loss (≤1 mm and ≤2 mm bone loss after 10 years). Implant survival in smokers and non-smokers was compared using the log-rank test. Both non-parametric tests and fixed model analysis were used to assess bone loss in both groups. Results: A total of 453 implants in 121 patients were included for survival analysis, and 397 implants in 121 patients were included for peri-implant bone-loss analysis. After a mean follow-up time of 11.38 years (SD 0.78; range 10.00–13.65), 33 implants out of 453 initially placed had failed in 21 patients, giving an overall survival rate of 92.7% and 82.6% on the implant and patient level, respectively. Cumulative 10 years’ survival rate was 81% on the patient level and 91% on the implant level. The hazard of implant loss in the maxilla was 5.64 times higher in smokers compared to non-smokers (p = 0.003). The hazard of implant loss for implants of non-smokers was 2.92 times higher in the mandible compared to the maxilla (p = 0.01). The overall mean bone loss was 0.97 mm (SD 1.79, range 0–17) at the implant level and 0.90 mm (SD 1.39, range 0–7.85) at the patient level. Smokers lost significantly more bone compared to non-smokers in the maxilla (p = 0.024) but not in the mandible. Only the maxilla showed a significant difference in the probability of implant success between smokers and non-smokers (≤1 mm criterion p = 0.003, ≤2 mm criterion p = 0.007). Taking jaw into account, implants in smokers experienced a 2.6 higher risk of developing peri-implantitis compared to non-smokers (p = 0.053). Conclusion: Dental implants with a fluoride-modified surface provided a high 10 years’ survival with limited bone loss. Smokers were, however, more prone to peri-implant bone loss and experienced a higher rate of implant failure, especially in the upper jaw. The overall bone loss over time was significantly higher in smoking patients, which might be suggestive for a higher peri-implantitis risk. Hence, smoking cessation should be advised and maintained after implant placement from the perspective of peri-implant disease prevention.

Long-term clinical performance of flapless implant surgery compared to the conventional approach with flap elevation: A systematic review and meta-analysis

BACKGROUND

The conventional implant approach involves flap elevation, which may result in increased soft tissue and bone loss and postoperative morbidity. The flapless surgical technique, aided by three-dimensional medical imaging equipment, is regarded as a possible alternative to the conventional approach to alleviate the above issues. Several studies have been performed regarding the role of flapless implant surgery. However, the results are inconsistent and there is no robust synthesis of long-term evidence to better inform surgeons regarding which type of surgical technique is more beneficial to the long-term prognosis of patients in need of implant insertion.

AIM

To compare the long-term clinical performance after flapless implant surgery to that after the conventional approach with flap elevation.

METHODS

PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and grey literature databases were searched from inception to 23 September 2019. Randomised controlled trials (RCTs) and cohort studies comparing the long-term clinical performance after flapless implant surgery to that after the conventional approach over a follow-up of three years or more were included. Meta-analyses were conducted to estimate the odds ratios (ORs) or mean differences (MDs) and their 95% confidence intervals (CIs) between the long-term implant survival rate, marginal bone loss, and complication rate of the flapless and conventional groups. Subgroup analyses were carried out to account for the possible effects of the guided or free-hand method during flapless surgery.

RESULTS

Ten articles, including four RCTs and six cohort studies, satisfied the eligibility criteria and nine of them were included in the meta-analysis. There was no significant difference between the long-term implant survival rate [OR = 1.30, 95%CI (0.37, 4.54), P = 0.68], marginal bone loss [MD = 0.01, 95%CI (-0.42, 0.44), P = 0.97], and complication rate [OR = 1.44, 95%CI (0.77, 2.68), P = 0.25] after flapless implant surgery and the conventional approach. Moreover, subgroup analyses revealed that there was no statistically significant difference between the implant survival rate [guided: OR = 1.52, 95%CI (0.19, 12.35), P = 0.70]; free-hand: n = 1, could not be estimated), marginal bone loss [guided: MD = 0.22, 95%CI (-0.14, 0.59), P = 0.23; free-hand: MD = -0.27, 95%CI (-1.10, 0.57), P = 0.53], or complication rate [guided: OR = 1.16, 95%CI (0.52, 2.63), P = 0.71; free-hand: OR = 1.75, 95%CI (0.66, 4.63), P = 0.26] in the flapless and conventional groups either with use of the surgical guide or by the free-hand method.

CONCLUSION

The flapless surgery and conventional approach had comparable clinical performance over three years or more. The guided or free-hand technique does not significantly affect the long-term outcomes of flapless surgery.

Bone formation around two titanium implant surfaces placed in bone defects with and without a bone substitute material: A histological, histomorphometric, and micro-computed tomography evaluation

OBJECTIVE

To evaluate the histological and microtomographic response of peri-implant bone tissue around titanium implants with different surface treatments, placed in bone defects filled or not filled with bone substitute materials.

MATERIALS AND METHODS

Thirty rabbits were divided into two groups according to the implant surface treatment. A bone defect was created in both tibias of all the rabbits, followed by the placement of one implant in each of these defects. On the left tibia, the defect was filled with a blood clot (BC), and on the right tibia, the defect was filled with biphasic hydroxyapatite/β-tricalcium-phosphate (HA/TCP); thus, there were four groups in total: BC-N: bone defect filled with a BC and porous surface titanium implant (control group); BC-A: bone defect filled with a BC and porous-hydrophilic surface titanium implant; HA/TCP-N: bone defect filled with a bone substitute material and porous surface titanium implant; HA/TCP-A: bone defect filled with a bone substitute material and porous-hydrophilic surface titanium implant. The animals were submitted for euthanasia at three distinct periods: 15, 30, and 60 days after implant installation. The samples were evaluated histologically and histometrically, to assess the quantity and quality of cells and the remaining bone substitute material in the grafted areas. The bone quantity was assessed by micro-computed tomography (CT).

RESULTS

For both surface types, the presence of a bone substitute material led to higher values in all evaluated micro-CT parameters, except in the bone surface/volume ratio parameter. No significant statistical difference was found for new bone formation between the four groups (P < .05; CI 95%). At all periods, the HA/TCP-A group had a higher percentage of new bone formation.

CONCLUSION

These results suggest that a porous hydrophilic surface in the presence of bone substitute material can accelerate peri-implant bone tissue formation.

The effectiveness of immediate implant placement for single tooth replacement compared to delayed implant placement: A systematic review and meta-analysis

AIM

To compare immediate implant placement (IIP) to delayed single implant placement (DIP, ≥3 months post-extraction) in terms of implant survival (primary outcome), surgical, clinical, aesthetic, radiographic and patient-reported outcomes (secondary outcomes).

MATERIALS AND METHODS

Two reviewers independently performed an electronic search in PubMed, Web of Science, EMBASE and Cochrane and a hand search to identify eligible studies up to May 2018. Only randomized controlled trials (RCTs) and non-randomized controlled studies (NRSs) comparing IIP to DIP with at least 1 year of follow-up were selected for a qualitative analysis and meta-analysis.

RESULTS

The search identified 3 RCTs and 5 NRSs out of 2,589 titles providing data on 473 single implants (IIP: 233, DIP: 240) that had been in function between 12 and 96 months. One RCT showed unclear risk of bias, whereas all other studies demonstrated high risk. Meta-analysis showed significantly lower implant survival for IIP (94.9%) as compared to DIP (98.9%) (RR 0.96, 95% CI [0.93; 0.99], p = 0.02). All were early implant failures. A subgroup meta-analysis demonstrated a trend towards lower implant survival for IIP when postoperative antibiotics had not been administered (RR: 0.93, 95% CI [0.86; 1.00], p = 0.07). This was not observed among studies including the administration of postoperative antibiotics (RR: 0.98, 95% CI [0.94; 1.02], p = 0.35). Meta-analyses showed similar probing depth (WMD 0.43 mm, 95% CI [-0.47; 1.33], p = 0.35) and aesthetic outcomes as assessed by the pink aesthetic score (standardized WMD -0.03, 95% CI [-0.46; 0.39], p = 0.88) for IIP and DIP. Data on marginal bone loss were conflicting and highly biased. Soft tissue recession was underreported and available data were highly biased. Patient-reported outcomes were underreported, yet both IIP and DIP seemed well tolerated.

CONCLUSION

Immediate implant placement demonstrated higher risk for early implant loss than DIP. There is a need for RCTs comparing IIP to DIP with CBCT analyses at different time points and data on midfacial recession with the preoperative status as baseline. In these studies, the need for hard and soft tissue grafting should also be evaluated.

Standard vs customized healing abutments with simultaneous bone grafting for tissue changes around immediate implants. 1-year outcomes from a randomized clinical trial

BACKGROUND

Immediate implants have shown risks of esthetic complications. The hypothesis was that a customized healing abutment could improve the peri-implant tissue healing.

PURPOSE

To evaluate and compare the soft and hard tissue healing around immediate implants that received bone grafting and a customized vs a standard healing abutment.

MATERIALS AND METHODS

Patients, who required tooth extraction and who received an immediate implant (with an alloplastic graft material) were randomly assigned to a customized or a standard healing abutment group. Clinical and radiographic examinations were taken at baseline, at 4 and 12 months.

RESULTS

Twenty-five patients out of 61 were excluded from the study because unsuitable for immediate implantation. In total, 36 patients were randomized in the two groups. There were 17 females and 19 males (age range 23-77). No prosthetic or implant failure was registered during the study period. The Papilla Index was significantly higher in the customized than in the standard group at 4 and 12 months (P = .0002). The bone loss at mesial sites was significantly higher in the control than in the test group (P = .0014).

CONCLUSION

The customized healing abutment group showed the most favorable outcomes (in terms of PI and MBL) in case of immediate implant that received a peri-implant bone grafting procedure.

A Systematic Review of Survival Rates of Osseointegrated Implants in Fully and Partially Edentulous Patients Following Immediate Loading

Background: The aim of this systematic review was to evaluate the survival rates of immediately loaded implants after at least five years. Besides implant failure, the amount of marginal bone loss around implants and the complication type were assessed. Methods: The electronic search was undertaken on Medline, Scopus, and Cochrane Central Register of Controlled Trials using key terms such as: “immediate loading”, “immediate function”, “immediate restoration”, “immediate temporization”, “dental implants”, “fully edentulous patients”, “partially edentulous patients”. The search terms were combined using the Boolean operators AND, OR. The last electronic search was performed on 15 February 2018. Two authors independently screened the studies, extracted the data, and assessed the risk-of bias. The main outcomes recorded for each study were: implant and prosthesis success and survival, marginal bone level change, incidence and type of complications. Kaplan–Meier analysis was used to estimate cumulative survival rates. Results: Thirty-four prospective studies with at least five-year follow-up, published between 2007 and 2017 were included. A total of 5349 immediately loaded implants in 1738 patients were analyzed. The mean follow-up was 72.4 months (median 60 months, 95% confidence intervals (CI): 64.53, 80.25 months, range 60 to 147 months). The mean weighted implant survival was 97.4% (median 98.15%, 95% CI: 96.29%, 98.54%, range 83.80% to 100%). Cumulative survival rate of implants placed in the mandible was significantly higher than for the maxilla (p < 0.01). No significant difference in failure rate was found among the types of prosthesis employed (p = 0.27). The mean peri-implant bone level change at the end of the follow-up in each study ranged from 0.3 to 1.7 mm. Conclusion: Immediate loading of implants appears to have long-term predictability and success rate under well-defined circumstances.

Performance of bone-level implants with conical connections in the anterior maxilla: A 5-year prospective cohort study

OBJECTIVES

To assess clinical, radiographic and aesthetic outcomes, and satisfaction of patients treated with single implant restorations in the maxillary aesthetic region 5 years after final restoration.

MATERIAL AND METHODS

Sixty patients (29 male/31 female, mean age 37 years) with a missing anterior tooth in the maxilla (39 central incisors/10 lateral incisors/5 cuspids/6 first premolars) received a bone-level implant with conical connection. In 29 patients, a bone augmentation procedure was necessary before implant placement (autogenous bone grafts mixed with spongiosa granules). All implants (12 with 3.3 mm diameter/ 48 with 4.1 mm diameter) were loaded after 3 months of submerged healing. The restoration consisted of an individually designed full-zirconia abutment veneered with porcelain. Follow-up with clinical and radiographic assessment was conducted until 60 months after the final restoration. Aesthetic outcome of the restoration was determined with the Pink Esthetic Score-White Esthetic Score (PES-WES). Patient satisfaction was assessed with a VAS scale and satisfaction questionnaire.

RESULTS

Fifty patients completed the 5-year follow-up. Implant survival was 100%, restoration survival 98%. Mean bone-level change was -0.13 ± 0.66 mm with a median (IQR) pocket probing depth of 2.75 [2.25; 3.25]. The mean PES and WES scores were 6.6 ± 1.7 and 7.8 ± 1.5, respectively. Patient satisfaction was high (92.1 ± 7.8 on 100 mm VAS scale). There were no differences between patients with or without a bone augmentation procedure.

CONCLUSION

Bone-level implants with a conical connection are a reliable treatment option in single-tooth replacements in the maxillary aesthetic zone.

The effects of hard and soft tissue grafting and individualization of healing abutments at immediate implants: an experimental study in dogs

Purpose

To evaluate the effects of intra-alveolar socket grafting, subepithelial connective tissue grafts, and individualized abutments on peri-implant hard and soft tissue outcomes following immediate implant placement.

Methods

This randomized experimental study employed 5 mongrel dogs, with 4 sites per dog (total of 20 sites). The mesial roots of P3 and P4 were extracted in each hemimandible and immediate dental implants were placed. Each site was randomly assigned to 1 of 4 different treatment groups: standardized healing abutment (control group), alloplastic bone substitute material (BSS) + standardized healing abutment (SA group), BSS + individualized healing abutment (IA group), and BSS + individualized healing abutment + a subepithelial connective tissue graft (IAG group). Clinical, histological, and profilometric analyses were performed. The intergroup differences were calculated using the Bonferroni test, setting statistical significance at P<0.05.

Results

Clinically, the control and SA groups demonstrated a coronal shift in the buccal height of the mucosa (0.88±0.48 mm and 0.37±1.1 mm, respectively). The IA and IAG groups exhibited an apical shift of the mucosa (−0.7±1.15 mm and −1.1±0.96 mm, respectively). Histologically, the SA and control groups demonstrated marginal mucosa heights of 4.1±0.28 mm and 4.0±0.53 mm relative to the implant shoulder, respectively. The IA and IAG groups, in contrast, only showed a height of 2.6 mm. In addition, the height of the mucosa in relation to the most coronal buccal bone crest or bone substitute particles was not significantly different among the groups. Volumetrically, the IA group (−0.73±0.46 mm) lost less volume on the buccal side than the control (−0.93±0.44 mm), SA (−0.97±0.73 mm), and IAG (−0.88±0.45 mm) groups.

Conclusions

The control group demonstrated the most favorable change of height of the margo mucosae and the largest dimensions of the peri-implant soft tissues. However, the addition of a bone substitute material and an individualized healing abutment resulted in slightly better preservation of the peri-implant soft tissue contour.

Accuracy of Customized Prefabricated Screw-Type Immediate Provisional Restorations after Single-Implant Placement

Limited evidence is available comparing the differences between pre-operative and post-operative 3D implant positions from the viewpoint of prosthetics. We aimed to investigate the differences between preplanned positions of virtual provisional restorations and their actual positions following fully guided single-implant placement. Ten maxillary typodonts with missing right central incisors were imaged using cone-beam computed tomography, and digital impressions were obtained using an intraoral scanner. These data were imported into implant-planning software, following which the provisional restorations were designed. After data superimposition, an appropriate implant position was determined, and a computer-assisted implant surgical guide was designed for each typodont. Orders generated from the implant-planning software were imported into relevant computer-aided design software to design the custom abutments. The abutments, provisional restorations, and surgical guides were fabricated, and each restoration was cemented to the corresponding abutments, generating a screw-type immediate provisional restoration. The implants were placed using the surgical guides, and the screw-type provisional restorations were engaged to the implants. The typodonts were then rescanned using the intraoral scanner. The restorations designed at the treatment planning stage were compared with those in the post-operative scan using metrology software. The angular deviation around the central axis of the implant was measured, and the differences in the crown position were converted to root mean square (RMS) values. The post-operative provisional restorations exhibited an absolute angular deviation of 6.94 ± 5.78° and an RMS value of 85.8 ± 20.2 µm when compared with their positions in the pre-operative stage. Within the limitations of the present in vitro study, the results highlight the potential application of customized prefabricated immediate provisional restorations after single-implant placement.

The clinical performance of all-ceramic implant-supported single crowns: A systematic review and meta-analysis

OBJECTIVE

This review aimed at evaluating the survival and technical complication rates of all-ceramic implant-supported single crowns (SC).

MATERIAL AND METHODS

Three electronic databases were searched for clinical studies conducted at ≥ 15 patients examining implant-supported all-ceramic SCs over ≥ 12 months. Survival rates of implants and restorations plus technical complication rates of SCs were calculated and tested for statistical correlation with confounding variables. Statistical analysis was performed using a negative binomial distribution model to calculate 5- and 10-year survival and complication estimates.

RESULTS

Forty-one included studies reported on implant-supported SCs made of veneered and monolithic high-strength oxide ceramics, monolithic, and veneered glass-based ceramics and of a monolithic resin-nano-ceramic (RNC). Survival estimates for SCs of 93% (95% CI: 86.6%-96.4%) after 5 years and 94.4% (95% CI: 91.1%-96.5%) after 10 years were calculated, corresponding values for implant survival were 95.3% (95% CI: 90.6%-97.7%) and 96.2% (95% CI: 95.1%-97.1%). Technical complication rates after 5/10 years were as follows: chipping 9.0% (95% CI: 5.4%-14.8%)/2.7% (95% CI: 2.1%-3.5%), framework fractures 1.9% (95% CI: 0.7%-4.9%)/1.2% (95% CI: 1%-1.5%), screw loosening 3.6% (95% CI: 1.6%-8.4%)/5.2% (95% CI: 3.6%-7.5%), and decementations with 1.1% (95% CI: 0.4%-2.8%) after 5 years. Some confounding variables influenced the above-mentioned estimates significantly.

CONCLUSIONS

All-ceramic implant-supported SCs showed-with the exception of a RNC material-high survival rates. However, failures and technical complications occurred which have to be considered when informing patients on the treatment with implant-supported all-ceramic SCs.

Immediate and flapless implant insertion and provisionalization using autogenous bone grafts in the esthetic zone: 5-year results

OBJECTIVES

As the 2-year results for immediately inserted and provisionalized implants have been reported, it remained an open issue, whether the initially high success rates and the esthetic outcome remain stable for longer observation periods. Therefore, this prospective study examines the 5-year hard and soft tissue changes at implants placed in the anterior maxilla.

MATERIAL AND METHODS

Meanwhile, 37 microthreaded implants were placed in 21 patients into extraction sockets with and without facial bone deficiencies by a flapless approach. Facial gaps and bony defects were grafted with autogenous bone chips. The implants were immediately provisionalized. The primary outcome parameters were the interproximal marginal bone level and the thickness of the facial bony wall. Implant success and Pink Esthetic Score (PES) were considered as secondary outcome parameters.

RESULTS

Two patients with four implants withdrew from the study (dropouts), and the remaining 33 implants were still in function at a follow-up period of 68 months. Marginal bone height averaged 0.04 mm coronal to the implant shoulder. The thickness of the facial bony lamellae increased significantly between pre-op examination and 1-year follow-up (p = .002) and thereafter remained stable. Within 5 years of follow-up, 24 of 33 implants were clinically stable, free of signs and symptoms, and showed bone loss less than 1 mm. The mean PES ratings improved slightly from 10.7 pre-operatively to 11.7 at the last follow-up (p = .02).

CONCLUSIONS

Interproximal marginal bone levels, survival rates, and esthetic results remain stable at the 5-year follow-up in implants used in an immediate insertion, reconstruction, and provisionalization concept. Facial marginal bone levels decreased slightly; however, this reduction did not affect the PES so far.

Influence of soft tissue grafting, orofacial implant position, and angulation on facial hard and soft tissue thickness at immediately inserted and provisionalized implants in the anterior maxilla

BACKGROUND

Resorption of hard and soft tissues following immediate implant insertion is frequently reported. Data regarding the influencing factors on facial tissue thickness are rare.

PURPOSE

This retrospective study investigated the impact of connective tissue grafting, the orofacial angulation and position of immediately inserted and provisionalized implants on the facial hard and soft tissue thickness in the anterior maxilla within a 1- to 5-year follow-up.

MATERIAL AND METHODS

Implants with the prerequisite of having preoperative and postoperative cone beam computed tomography (CBCT) and a follow-up of 1 to 5 years were included. Facial bone deficiencies were grafted flaplessly with autogenous bone in all sites. In a subgroup of implants additional connective tissue grafting was performed, whereas the remaining implants were not grafted with soft tissue. The orofacial tooth and implant angulation, the change of horizontal position and the facial bone thickness were measured by CBCT, the facial mucosa thickness by an ultrasonic device.

RESULTS

In total, 76 implants were placed in 55 patients. Sixty-nine sites showed a facial bone defect. Thirty-eight received a connective tissue graft additionally. All implants were still in function after a mean follow-up of 36 months. The mean thickness of the facial mucosa was 1.72 mm at 1 mm, 1.63 mm at 4 mm, 1.52 mm at 6 mm, and 1.66 mm at 9 mm apically to mucosal margin. The bone thickness was 0.02, 0.25, and 0.36 mm initially and 1.32, 1.26, and 1.11 mm finally at 1, 3, and 6 mm apically to implant shoulder level. Mixed model analysis revealed an impact of the preoperative bone status on the facial bone increase. The facial soft tissue thickness was significantly influenced by the gingival biotype.

CONCLUSIONS

The results indicate that an initial severe hard tissue defect allows for significant bone regeneration. The facial soft tissue thickness is primarily influenced by the gingival biotype.

Clinical relevance of dimensional bone and soft tissue alterations post-extraction in esthetic sites

The key to achieving pleasing esthetics in implant dentistry is a thorough understanding of the biological processes driving dimensional bone and soft tissue alterations post-extraction. The aim of the present report is first to characterize the extent of bone and soft tissue changes post-extraction and second to identify potential factors influencing tissue preservation in order to facilitate successful treatment outcomes. The facial bone wall thickness has been identified as the most critical factor influencing bone resorption and can be used as a prognostic tool in order to identify sites at risk for future facial bone loss subsequent to tooth extraction. Clinical studies indicated that thin bone wall phenotypes exhibiting a facial bone wall thickness of 1 mm or less revealed progressive bone resorption with a vertical loss of 7.5 mm, whereas thick bone wall phenotypes showed only minor bone resorption with a vertical loss of 1.1 mm. This is in contrast to the dimensional soft tissue alterations. Thin bone wall phenotypes revealed a spontaneous soft tissue thickening after flapless extraction by a factor of seven, whereas thick bone wall phenotypes showed no significant changes in the soft tissue dimensions after 8 weeks of healing. In sites exhibiting a limited bone resorption rate, immediate implant placement may be considered. If such ideal conditions are not present, other timing protocols are recommended to achieve predictable and pleasing esthetics. Socket preservation techniques for ridge preservation utilizing different biomaterials and/or barrier membranes often result in a better maintenance of tissue volumes, although the inevitable biological process of post-extraction bone resorption and bone modeling cannot be arrested. In summary, the knowledge of the biological events driving dimensional tissue alterations post-extraction should be integrated into the comprehensive treatment plan in order to limit tissue loss and to maximize esthetic outcomes.

Implant placement post extraction in esthetic single tooth sites: when immediate, when early, when late?

Implant placement in post-extraction sites of single teeth in the esthetic zone has been a topic of great interest in the field of implant dentistry since 1990. Triggered by the development of guided bone regeneration, the concept of immediate implant placement became quite popular in the 1990s. In the past 12 years, however, the dental community has begun to focus increasingly on the esthetic outcomes of post-extraction implant placement and several studies indicated a significant risk for the development of mucosal recessions with immediate implants. Parallel with this, significant progress has been made in the understanding of tissue biology in terms of hard and soft tissue alterations post extraction, based on preclinical, clinical and radiological studies. This knowledge has helped better to understand the etiology of these esthetic complications with immediate implant placement. The present review first analyzes the various phases of the development of therapeutic strategies over the years for post-extraction implant placement in single tooth sites in the esthetic zone. It presents the current knowledge concerning the terminology with immediate, early and late implant placement, the risk factors for the development of esthetic complications, and the selection criteria for the various treatment options. In the second part, clinical recommendations are given, since a clinician active in this field of implant therapy can use all treatment options depending on the preoperative analysis including a 3D cone beam computed tomography. The selection criteria for all four treatment options are presented and documented with typical case reports to illustrate the current treatment approaches applied in daily practice.

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.

Histological Evaluation of the Effect of Concentrated Growth Factor on Bone Healing

OBJECTIVES

The aim of this study was to evaluate the effects of concentrated growth factors (CGF) on the healing of peri-implant bone defects in an animal model.

STUDY DESIGN

Twenty 4-month-old New Zealand White rabbits, each with an average weight of 3.5 kg, were used in this blinded, prospective, experimental study. Two implants were placed and 2 peri-impant defects were prepared in each rabbit tibia. Bone defects were created monocortically in the tibia of each rabbit using a trephine burr with a diameter of 8 mm. The implants were installed in each hole. The rabbits were divided into 4 groups: in group E, the defect was left empty; in group CGF, the defects were filled only with CGF; in group AB, the defects were filled with autogenous bone; and in group AB+CGF, the defects were filled with autogenous bone and CGF. The animals were euthanized at week 8 postimplantation. All implants from the 20 animals were fixed in 10% formalin and evaluated histomorphometrically.

RESULTS

The mean defect area was highest in group E and lowest in group CGF+AB (P <0.05). The area of the defect differed significantly between groups AB and CGF+AB (P <0.05), but not between groups CGF and E. Implant-to-bone contact was lowest in group E. In the defect areas of groups CGF, AB and CGF+AB, a small amount of new bone formed around the implant.

CONCLUSIONS

In this animal model of a peri-implant bone defect, restoration was achieved using a combination of autogenous bone and CGF. Further studies are needed to determine the behavior of CGF when used in the repair of bone defects in humans.

Soft Tissue Changes Around Immediately Placed Implants: A Systematic Review and Meta-Analyses With at Least 12 Months of Follow-Up After Functional Loading

BACKGROUND

Immediate implant placement (IIP) is predictable but can lead to esthetic challenges, including midfacial recession (MFR) and papillary height (PH) loss. The aim of this systematic review is to examine the effect of IIP on MFR and PH after at least 12 months of functional loading.

METHODS

Literature review of the Cochrane and MEDLINE electronic databases and hand search up to January 2016 identified eligible studies. Four reviewers independently assessed data quality and methodology.

RESULTS

A total of 106 articles satisfied the inclusion criteria. Twelve studies qualified for three meta-analyses. MFR was slightly less in conventional implant placement (CIP) than in IIP, but the result was not statistically significant (mean difference [MD] -0.064 mm; P = 0.687). Similarly, there was better PH maintenance in CIPs, with statistical significance for distal PH (DPH) only (cumulative PH: MD -0.396, P = 0.010; DPH: MD -0.765, P <0.001; mesial PH [MPH]: MD -0.285, P = 0.256). MFR was slightly less in IIP with thick versus thin biotypes, but not statistically significantly different (MD -0.373, P = 0.243). Pooled data showed statistically significantly less MFR and better PH maintenance in IIP with thick biotype (MFR: MD -0.478, P <0.001; cumulative PH: MD -0.287, P <0.001; MPH: MD -0.288, P <0.001; DPH: MD -0.310, P <0.001). Non-significantly less MFR (MD 0.253, P = 0.384) and significantly better PH maintenance were found in IIP with immediate provisionalization versus conventional restoration (MD -0.519, P = 0.028).

CONCLUSIONS

IIP in thick biotype and with immediate provisionalization had less MFR and better PH than IIP in thin biotype or with delayed restoration. However, these findings should be interpreted with caution due to high heterogeneity, which was calculated using comprehensive meta-analysis statistical software that took into account sample size and different treatment groups, and limited qualified studies.

The Effect of Osteotomy Dimension on Implant Insertion Torque, Healing Mode, and Osseointegration Indicators: A Study in Dogs

PURPOSE

This study investigated the effect of the osteotomy diameter for implant placement torque and its effect on the osseointegration.

MATERIALS AND METHODS

Eight male beagle dogs received 48 implants (3.75 mm × 10 mm) in their right and left radius, 3 implants per side and allowed to heal for 3 weeks. Three experimental groups were evaluated. Group 1: implant with an undersized osteotomy of 3.0 mm; group 2: osteotomy of 3.25 mm, and group 3: osteotomy of 3.5 mm. The insertion torque was recorded for all implants. Histological sectioning and histometric analysis were performed evaluating bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO).

RESULTS

Implants of group 1 presented statistically higher insertion torque than those of groups 2 and 3 (P < 0.01). No differences in BIC or BAFO were observed between the groups. From a morphologic standpoint, substantial deviations in healing mode were observed between groups.

CONCLUSION

Based on the present methodology, the experimental alterations of surgical technic can be clinically used with no detrimental effect over the osseointegration process.

Clinical and radiographic outcome following immediate loading and delayed loading of single-tooth implants: Randomized clinical trial

BACKGROUND

Immediate loading of single implants is generally considered a reliable procedure.

PURPOSE

The objective of the present prospective randomized clinical study was to compare the overall treatment outcome following immediate loading (IL) and delayed loading (DL) of single implants after 1 year of follow-up.

MATERIALS AND METHODS

Patients with a missing maxillary tooth (15-25) were randomly assigned to IL or DL. The protocol included implant installation in healed sites, immediate loading, delayed loading, temporary screw-retained restoration, and replacement with a permanent single implant crown. Outcome measures were implant survival, marginal bone level, soft tissue changes, papillae index, pink, and white esthetic score (PES and WES), patient judged aesthetics, and oral health impact profile (OHiP-14).

RESULTS

Implant survival rate was 100% and 96% for IL and DL, respectively. Implant success rate was 96% and 88% for IL and DL, respectively. Statistically significant lower papilla index scores were found in the IL group at temporary crown and definitive crown placement. An overall statistically significant improvement after 12 months for PES, WES and OHIP-14 was found.

CONCLUSION

This prospective randomized study showed that single implants in the maxilla can present satisfactory results with respect to either immediate loading or delayed loading after 12 months.

Evaluation of the papilla level adjacent to implants placed in fresh, healing or healed sites: A systematic review

A better understanding of factors that can lead to papilla formation or recession, such as the type of site where the implant was placed, is of fundamental importance to the aesthetic success of the rehabilitation. The aim of this study was to perform a systematic review of the literature regarding the formation or recession of papilla adjacent to implants placed in fresh, healing or healed sites. The protocol for this study was registered in the PROSPERO database (registration number CRD 42016033784). An electronic search was performed by two independent reviewers who applied the inclusion and exclusion criteria on the PubMed/MEDLINE, Scopus, and Embase databases from January 2005 up to February 2016. The initial screening yielded 1,065 articles, from which 15 were selected for a systematic review after applying the inclusion and exclusion criteria. Nine studies compared fresh and healed sites, four studies compared healing and healed sites, one study compared fresh and healing sites, and one study analysed all three sites. The majority of studies identified by this systematic review showed no difference between groups after the longer follow-up period. The sites where the implants were placed did not have a long-term influence on papilla formation or recession.

Immediate implant placement into fresh extraction sockets versus delayed implants into healed sockets: A systematic review and meta-analysis

The aim of this systematic review and meta-analysis was to compare the survival rate of the implants and the peri-implant tissue changes associated with implants inserted in fresh extraction sockets and those inserted in healed sockets. This review has been registered at PROSPERO under the number CRD42016043309. A systematic search was conducted by two reviewers independently in the databases PubMed/MEDLINE, Embase, and the Cochrane Library using different search terms; articles published until November 2016 were searched for. The searches identified 30 eligible studies. A total of 3,049 implants were installed in a total of 1,435 patients with a mean age of 46.68 years and a minimum of 6 months of follow-up. The survival rate of delayed implants (98.38%) was significantly greater than immediate implants (95.21%) (p=.001). For the marginal bone loss (p=.32), implant stability quotients values (p=.44), and pocket probing depth (p=.94) there was no significant difference between the analysed groups. The immediate implants placed in fresh sockets should be performed with caution because of the significantly lower survival rates than delayed implants inserted in healed sockets.

Development and capture of soft tissue contours at time of implant placement

A technique is described which will generate a customized healing abutment for a dental implant to allow the development of ideal soft tissue contours. With implant position and soft tissue contours defined at surgery, customized impression techniques can be used to capture those details and help generate the definitive implant-supported restoration. This workflow reduces the number of patient visits.

Long-Term Effect of Surface Roughness and Patients' Factors on Crestal Bone Loss at Dental Implants. A Systematic Review and Meta-Analysis

Publications from 2011 to 2015 were selected to evaluate effect of implant surface roughness on long-term bone loss as surrogate for peri-implantitis risk. 87 out of 2,566 papers reported the mean bone loss after at least 5 years of function. Estimation of the proportion of implants with bone loss above 1, 2, and 3 mm as well as analysis the effect of implant surface roughness, smoking, and history of periodontitis was performed. By means of the provided statistical information of bone loss (mean and standard deviation) the prevalence of implants with bone loss ranging from 1 to 3 mm was estimated. The bone loss was used as a surrogate parameter for "peri-implantitis" given the fact that "peri-implantitis" prevalence was not reported in most studies or when reported, the diagnostic criteria were unclear or of dubious quality. The outcome of this review suggests that peri-implant bone loss around minimally rough implant systems was statistically significant less in comparison to the moderately rough and rough implant systems. No statistically significant difference was observed between moderately rough and rough implant systems. The studies that compared implants with comparable design and different surface roughness, showed less average peri-implant bone loss around the less rough surfaces in the meta-analysis. However, due to the heterogeneity of the papers and the multifactorial cause for bone loss, the impact of surface roughness alone seems rather limited and of minimal clinical importance. Irrespective of surface topography or implant brand, the average weighted implant survival rate was 97.3% after 5 years or more of loading. If considering 3 mm bone loss after at least 5 years to represent the presence of "peri-implantitis," less than 5% of the implants were affected. The meta-analysis indicated that periodontal history and smoking habits yielded more bone loss.

Influence of bicortical techniques in internal connection placed in premaxillary area by 3D finite element analysis

The aim of study was to evaluate the stress distribution in implant-supported prostheses and peri-implant bone using internal hexagon (IH) implants in the premaxillary area, varying surgical techniques (conventional, bicortical and bicortical in association with nasal floor elevation), and loading directions (0°, 30° and 60°) by three-dimensional (3D) finite element analysis. Three models were designed with Invesalius, Rhinoceros 3D and Solidworks software. Each model contained a bone block of the premaxillary area including an implant (IH, Ø4 × 10 mm) supporting a metal-ceramic crown. 178 N was applied in different inclinations (0°, 30°, 60°). The results were analyzed by von Mises, maximum principal stress, microstrain and displacement maps including ANOVA statistical test for some situations. Von Mises maps of implant, screws and abutment showed increase of stress concentration as increased loading inclination. Bicortical techniques showed reduction in implant apical area and in the head of fixation screws. Bicortical techniques showed slight increase stress in cortical bone in the maximum principal stress and microstrain maps under 60° loading. No differences in bone tissue regarding surgical techniques were observed. As conclusion, non-axial loads increased stress concentration in all maps. Bicortical techniques showed lower stress for implant and screw; however, there was slightly higher stress on cortical bone only under loads of higher inclinations (60°).