Partial fixed dental prostheses fabricated using fiber-reinforced composite resin supported by short and extra-short implants: A case series

PURPOSE

This study aimed to evaluate the 10-year outcomes of partial fixed dental prostheses (P-FDPs) fabricated using metal-free fiber-reinforced composite (FRC) resin frameworks veneered with composite resin and supported by short and extra-short implants.

METHODS

This study included 28 patients with 38 FRC prostheses supported by 96 implants. Implant and prosthesis survival and success rates were evaluated using Kaplan-Meier analysis.

RESULTS

The 10-year implant survival and success rate, as determined by Kaplan-Meier analysis, was 96.9%, and the prosthesis survival and success rates were 94.7% and 92.0%, respectively. None of the parameters under investigation were significantly correlated with prosthetic survival or successful outcomes, but three parameters were correlated with higher peri-implant bone levels: implant placement in the mandible as opposed to the maxilla, shorter P-FDP spans, and natural teeth on the opposing arch.

CONCLUSIONS

FRC P-FDPs supported by short and extra-short implants presented high, up to 10-year, survival and success rates, when used to restore partially edentulous arches.

Long-Term Clinical Outcomes of Single Crowns or Short Fixed Partial Dentures Supported by Short (≤6 mm) Dental Implants: A Systematic Review

Long-term clinical outcomes of short dental implants (≤6 mm) supporting single crowns or short fixed partial dentures have been reported differently in different studies and need more clarification. This systematic study evaluated the rate of bone loss (BL), the durability of implants equal to or shorter than 6 mm supporting single crowns or short fixed partial dentures, and prosthetic-related side effects during 5 years of follow-up. Five databases (PubMed, MEDLINE, Scopus, Google Scholar, and Cochrane) were electronically and manually searched for longitudinal studies with a follow-up period of 5 years or more until January 2023. The study question was, "Does the implant equal to or shorter than 6 mm affect BL and survival rate of the implant-supported prosthesis after 5 years of follow-up?". From 752 identified articles, nine studies were selected for further evaluation. After 5 years of follow-up, most studies had more than 90% survival rate and the maximum BL was 0.54 mm. Still, in internal and external connections, these changes were not substantial. For example, screw loosening was the most common problem with implanted prostheses. Implants of 6 mm or shorter are a suitable treatment option in atrophic ridges with good durability and fewer side effects during a follow-up period of more than 5 years.

Rehabilitation of distal extension maxillary ridges with fixed and removable implant-supported prostheses: Preliminary 12-month randomized clinical trial

PURPOSE

This trial evaluated clinical outcomes of fixed and removable implant-supported prostheses for rehabilitation of atrophied distal extension maxillary ridges.

MATERIALS AND METHODS

A total of 54 participants with atrophied distal extension maxillary ridges were randomly assigned into three groups (n = 18/group). Group I (SLF); participants treated with fixed restoration supported by three long implants after sinus augmentation, Group II (SF); participants treated with fixed restoration supported by one long and two short implants, and Group III (OD): participants treated with removable partial denture assisted by one long implant that was placed mesial to maxillary sinus (IARPD). Modified plaque index (MPI), modified gingival index (MGI), pocket depth (PD), implant stability (IS), and crestal bone loss (CBL) were measured after prosthesis insertion (T0), 6 (T6), and 12 months (T12) after insertion. Patient satisfaction was measured at T12 using a visual analog scale (VAS).

RESULTS

The implant survival rates were 96.8%, 92.4%, and 84.6% for SLF, SF, and OD groups respectively. The SLF recorded the highest MPI, MGI, PD, and IS values, followed by the SF, and the OD showed the lowest values. The OD recorded the highest CBL followed by the SF and the SLF showed the lowest CBL. With exception of satisfaction with surgery and cleaning, SLF and SF groups recorded significantly higher patient satisfaction than the OD for all VAS questions.

CONCLUSION

Fixed restorations supported with either long or short implants were associated with improved implant stability, reduced bone loss, and increased patient satisfaction compared to implant-assisted RPDs. However, implant-assisted RPDs were associated with more favorable peri-implant soft tissue health and increased satisfaction with surgery, healing, and cleaning.

Clinical performance of short and extrashort dental implants with wide diameter: A systematic review with meta-analysis

STATEMENT OF PROBLEM

Rehabilitation with wide-diameter reduced-length implants has become popular for patients with minimal vertical bone. However, a consensus on the benefits of this approach is lacking.

PURPOSE

The purpose of this systematic review with meta-analysis was to evaluate the influence of wide compared with regular diameter on the clinical performance of short (<10 mm) and extrashort (≤6 mm) dental implants used for rehabilitations with single crowns, fixed partial dentures, or both, in the posterior region.

MATERIAL AND METHODS

A search in 6 databases was conducted to select randomized controlled trials (RCTs) and nonrandomized controlled trials (N-RCTs). Five meta-analyses were performed, where the risk ratio (RR) was evaluated. The certainty of evidence was evaluated, and the risk of bias was determined from the Joanna Briggs Institute checklist.

RESULTS

Fourteen articles were included, 272 wide- and 478 regular-diameter implants. One study presented a low, 3 an unclear, and 11 a high risk of bias. Meta-analyses showed no statistical difference: implant survival, short dental implants in N-RCTs (up to 1 year - RR 1.01 [0.98; 1.03], 1 to 5 years - RR 1.01 [0.94; 1.08], more than 5 years - RR 1.01 [0.97; 1.06]), extrashort dental implants in N-RCTs (RR 1.04 [0.90; 1.20]), RCTs (RR 1.05 [0.88; 1.25]); implant success in N-RCTs (RR 1.01 [0.97; 1.05]); prosthesis success in N-RCTs (RR 1.01 [0.97; 1.05]).

CONCLUSIONS

Short and extrashort dental implants with a wide and regular diameter appear to be clinically appropriate options for implant-supported posterior restorations, with high survival, success, and prosthesis success rates.

Performance of crowns cemented on a fiber-reinforced composite framework 5-unit implant-supported prostheses: in silico and fatigue analyses

OBJECTIVE

To characterize the biomechanical performance of fiber-reinforced composite 5-unit implant-supported fixed dental prostheses (FDPs) receiving individually milled crowns by insilico and fatigue analyses.

METHODS

Eighteen implant-supported five-unit fiber-reinforced composite frameworks with an individually prepared abutment design were fabricated, and ninety resin-matrix ceramic crowns were milled to fit each abutment. FDPs were subjected to step-stress accelerated-life testing with load delivered at the center of the pontic and at 2nd molar and 1st premolar until failure. The reliability of the prostheses combining all loaded data and of each loaded tooth was estimated for a mission of 50,000 cycles at 300, 600 and 900 N. Weibull parameters were calculated and plotted. Fractographic and finite element analysis were performed.

RESULTS

Fatigue analysis demonstrated high probability of survival at 300 N, with no significant differences when the set load was increased to 600 and 900 N. 1st and 2nd molar dataset showed high reliability at 300 N, which remained high for the higher load missions; whereas 1st premolar dataset showed a significant decrease when the reliability at 300 N was compared to higher load missions. The characteristic-strength of the combined dataset was 1252 N, with 1st molar dataset presenting higher values relative to 2nd molar and 1st premolar, both significantly different. Failure modes comprised chiefly cohesive fracture within the crown material originated from cracks at the occlusal area, matching the maximum principal strain location.

SIGNIFICANCE

Five-unit implant-supported FDP with crowns individually cemented in a fiber-reinforced composite framework presented a high survival probability. Crown fracture comprised the main failure mode.

Posterior jaws rehabilitation with < 7mm-short implants. A review

INTRODUCTION

The results with shorter and shorter implants have been revolutionizing the implantology scenario and are worthy of being well-analyzed and understood. This review aims to add further knowledge about the last 10-years observation period on < 7mm-short implants in the posterior atrophic jaws, better defining the indication of their use.

METHODS

From a Medline database research, systematic reviews, controlled and no- controlled trials (CT, n-CT) with ≥ 3years-follow-ups on <7 mm / ≥ 5mm-short implants (group A), and clinical studies with ≥ 1year-follow-up on 4mm-short implants (group B) were considered. The outcomes, in terms of implant survival rate (SR), marginal bone loss (MBL), and complications were analyzed according to the duration of follow-ups, implant site (maxilla and mandible), type of prosthesis (single crown or splinted units), vertically impaired or normal sites.

RESULTS

Thirty-four trials (28 for group A and six for group B) were selected. Group A: a mean follow up of 5,8 (3-10) years came out; pre-and post-loading SR range was 94.4- 100% and 89.6-100%, respectively; the range of MBL was 0.12-1.49; 50% of CT found less statistically significant surgical complications in comparison with standard implants (ST) in reconstructed sites, while major prosthetic problems were recorded with short -implants (SH) in 37.5% of CT; in no atrophied sites, a mean SR range of 86.7-100 % vs. 88-100 % and a total bone loss of 2 vs.1.6 for SH vs.ST emerged. Group B: the overall mean follow-up period was 2,3 years, and the pre-and post- SR ranges were 93-100 % and 87.5-100 %, respectively. The MBL range was 0.02- 0.63 mm. All RCT reported significantly fewer surgical complications with SH than with ST in reconstructed mandibles within one year. No prosthetic complications were reported for up to 5 years using no pontics or cantilevers fixed bridges.

CONCLUSIONS

Similar or even better results for SH than ST in terms of post-loading SR and MBL came out for < 7mm/ ≥ 5mm-short implants in atrophic bone regardless of the prosthetic solutions, with less surgical complications but a few more prosthetic problems; the good results up to 5 years for 4mm-short implants in mandibles are associated with splinted and no-risk prosthetic solutions.

Clinical Comparation of Extra-Short (4 mm) and Long (>8 mm) Dental Implants Placed in Mandibular Bone: A Systematic Review and Metanalysis

This systematic review (SR) aimed to evaluate implant survival rate, marginal bone loss (MBL), and biological/prosthetic complications of extra-short 4 mm dental implants. An electronic search without language or date restrictions was performed in five databases and in gray literature for articles published until August 2020. Prospective cohort studies and randomized clinical trials (RCTs) that evaluated the clinical performance of extra-short 4 mm dental implants were included. Studies were independently assessed for risk of bias using the Cochrane Collaboration’s tool. The protocol of this SR was registered in the PROSPERO database under number CRD42019139709. Four studies were included in the present SR. There was no significant difference in implant survival rate (p = 0.75) between extra-short 4 mm and long implants. After 12 months of function, the extra-short implants had a significantly (p = 0.003) lower marginal bone loss (MBL) rate when compared to long implants. Extra-short implants had a lower number of biological and prosthetic complications when compared to long implants. After 12 months of follow-up, extra-short 4 mm dental implants placed in the mandible exhibit satisfactory clinical outcomes concerning implant survival rate and MBL when compared to longer implants, with a low number of biological and prosthetic complications. A higher number of RCTs with longer follow-up is necessary for the future.

CT-based dentulous mandibular alveolar ridge measurements as predictors of crown-to-implant ratio for short and extra short dental implants

The purpose was to predict the crown-to-implant ratio variation in the edentulous posterior mandibles rehabilitated with short dental implants. Hence, vertical and horizontal dimensions of dentulous posterior mandibles in a sample of 18- to 25-year-olds were measured, and correlations of these dimensions with sex and site were investigated. Mandibular computed tomography scans from 100 subjects were considered. Vertical and horizontal bone and tooth measurements were taken at the sites of the second premolar (PM), and the mesial and distal roots of the first and second molars (M1m, M1d, M2m and M2d, respectively). A hypothetical crown-to-implant ratio (C/I R) was calculated assuming the insertion of short and extra short implants (5, 6 or 7 mm), at 1.5 mm from the inferior alveolar canal, maintaining the position of the existing occlusal plane. All vertical bone dimensions decreased from the PM to the M2d. Width measurements increased from the mesial (PM) to the distal sites (M1m, M1d, M2m and M2d). Males had significantly greater vertical and horizontal measurements than females at all sites. The mean C/I R was higher than 2 for all sizes of implant. The C/I R was lower for the second molar than for the second premolar, while it was similar for the first molar and the second premolar. Males had a higher C/I R than females. Computed tomography can be used to study the anatomical features of alveolar bone, and to predict some clinical aspects of prosthetic rehabilitation with implants, such as the crown-to-implant ratio in conditions of serious bone atrophy.

Influence of crown-to-implant ratio and different prosthetic designs on the clinical conditions of short implants in posterior regions: A 4-year retrospective clinical and radiographic study

BACKGROUND

Short implants (intra-bony length ≤ 8 mm) are generally considered as an alternative to bone augmentation in challenging situations; however, clinical evidence from large-scale studies with long follow-up regarding the application of short implants remains deficient.

PURPOSE

The present study aimed to assess the mid-term clinical outcomes of short implants supporting fixed prostheses in the posterior region, and to investigate the effects of the crown-to-implant ratio (C/I), and other patient-, implant-, prosthesis-relevant factors on the clinical conditions around short implants.

MATERIALS AND METHODS

180 Thommen short implants in 130 partially edentulous patients were enrolled in the study after 3 to 7 (mean 4.2) years of follow-up. Potential risk factors (patient sex and age, implant diameter and location, splinted vs single-tooth restorations, retention mode, anatomical and clinical C/I ratios) were evaluated according to the following outcomes: Implant survival, marginal bone loss (MBL), and mechanical and biological complications.

RESULTS

In total, four implants in four patients failed as a result of peri-implantitis. The cumulative survival rate was 97.8% for implant-based analysis. The peri-implant MBL around 180 short implants was 0.90 ± 0.78 mm. The mean clinical C/I ratio was 1.16 ± 0.36. Correlation analysis revealed that the influence of the clinical C/I ratio and patient age were significant for MBL (P < .05), whereas other potential risk factors showed no significant association with the outcome. Among 180 short implants, 24 cases (13.3%) had biological complications and 32 cases (17.8%) had mechanical complications, respectively. Peri-implant MBL and complication rates around splinted and non-splinted implants were not statistically different.

CONCLUSION

Within the limitations of this study, short implants supporting fixed prostheses in the posterior region achieved predictable clinical outcomes over a 3 to 7 year period. Within the range of 0.47 to 3.01, the higher the C/I ratio, the less the peri-implant MBL.

Excessive occlusal load on chemically modified and moderately rough titanium implants restored with cantilever reconstructions. An experimental study in dogs

OBJECTIVE

To evaluate the outcomes of excessively loaded implants.

MATERIAL AND METHODS

In five dogs, all mandibular premolars were extracted. After 3 months, six implants (three SLA® and three SLActive®) were placed (S). After 4 weeks, implants were restored: one single crown with stable occlusal contacts (SC), one crown and a cantilever unit with excessive occlusal contacts (OL), and a non-loaded implant (NL). Bleeding-on-probing (BoP), attachment level (AL), mucosal margin (GM) were assessed. Resonance frequency analysis (RFA) was assessed weekly. Standardized X-rays were taken at S, 4 and 24 weeks.

RESULTS

Similar findings were observed for SLA® and SLActive® implants regarding PlI, GI, GM, AL, and BL. No significant differences were detected between baseline and 24-weeks or between treatment modalities for all clinical parameters (p > .05). Six months after loading, RFA values were significantly greater than at implant placement. No significant differences between treatment modalities were found. Linear radiographic measurements yielded similar results between SLA® and SLActive® implants. SLA® OL implants yielded a statistically significant gain on peri-implant bone density over all other groups (p = .012). Radiographic results were confirmed by descriptive histology. Technically, loosened occlusal screws occurred in 13.3% (SC = 3.3%; OL = 10%), while abutment fractures totalized 23.3% (SC = 6.6%; OL = 16.6%).

CONCLUSIONS

Excessive occlusal load applied to implants (SLA® or SLActive®) restored with cantilevers did not cause loss of osseointegration or significant changes in their clinical, radiographic, or histologic outcomes. Early excessive occlusal load on SLA® implants promoted a gain in peri-implant bone density. Excessively loaded implants showed more technical complications.

Meta-analysis of randomized clinical trials comparing clinical and patient-reported outcomes between extra-short (≤6 mm) and longer (≥10 mm) implants

AIM

To compare the clinical outcomes of ≤6 mm extra-short implants (test group) versus ≥10 mm long implants (control group), with and without bone augmentation procedures.

MATERIALS AND METHODS

A systemic literature search of randomized clinical trials was performed using the PubMed (MEDLINE) and EMBASE databases. A quantitative meta-analysis was conducted to compare all the outcome variables. Meta-regression analysis determined the effect of bone augmentation procedures and the influence of other clinical covariates on the results.

RESULTS

Eighteen studies comprising 1,612 implants (793 extra-short and 820 long implants) were selected for the meta-analysis. No statistically significant difference in the survival rate was observed at 1 and 3 years (p > 0.05). Extra-short implants displayed less marginal bone loss (MBL) from both implant placement time points (1 and 3 years) and prosthetic placement (1 year), as well as less biological complications, surgical time and treatment cost (p < 0.05). Contrarily, a statistically significant small number of prosthetic complications were reported with long implants (p < 0.05).

CONCLUSIONS

Placement of extra-short implants (≤6 mm) presented as an equivalent option in the treatment of patients with an atrophic posterior arch up to 3-year follow-up. However, the long-term effectiveness of extra-short dental implants remains to be further studied.

Long-term follow-up of single crowns supported by short, moderately rough implants-A prospective 10-year cohort study

OBJECTIVES

To evaluate prospectively the clinical and radiographic outcomes after ten years of short (6 mm) implants with a moderately rough surface supporting single crowns in the posterior region.

MATERIAL AND METHODS

Forty 6 mm modified sandblasted large-grit acid-etched (mod-SLA), soft tissue level implants were installed in the distal segments of 35 consecutive patients. After 6 weeks of healing, abutments were tightened, and single porcelain-fused-to-metal crowns were cemented. Implant survival, marginal bone loss, and clinical crown/implant ratio were evaluated at various time intervals up to 10 years after loading.

RESULTS

Two out of the 40 implants were lost before loading, one implant was lost after 7 years because of peri-implantitis. One patient with two implants died and was excluded from analysis. Two patients did not come at the 10-year follow-up and were considered as drop out (2 implants). The survival rate was 91.7% (n = 36). Thirty-three implants were available for marginal bone loss evaluation. A mean marginal bone loss after 10 years of function was 0.8 ± 0.7 mm. Between 5 and 10 years, the loss was 0.2 ± 0.4 mm. No technical complications were registered during the 10-year period. The clinical crown/implant ratio increased with time from 1.6 at the delivery of the prosthesis to 2.0 after 10 years of loading with no increase between 5 and 10 years.

CONCLUSION

Short (6 mm) implants with a moderately rough surface supporting single crowns in the posterior region and loaded after 6-7 weeks maintained full function for at least 10 years with low marginal bone resorption.

Using Resonance Frequency Analysis to Compare Delayed and Immediate Progressive Loading for Implants Placed in the Posterior Maxilla: A Pilot Study

Objective:

Implants placed in the posterior region of the maxilla have a high incidence of implant failure due to poor bone quality, especially when immediate implant loading is needed. Immediate Progressive Loading (IPL) can enhance bone quality and may offer an alternative solution when Immediate Implant loading is needed.

Methods:

Six patients (one male and five females; 34-62 years old) were included in this study. Twelve implants were inserted in the posterior region of the maxilla. Resonance Frequency Analysis (RFA) was performed at the time of implant placement and after 1, 2, 3 and 6 months. ISQ (Implant Stability Quotient) values were compared between the Delayed Loading (DL) group after 2 months and the Progressive Loading (PL) group and between different time points for each group.

Results:

At implant placement, the mean ISQ values for PL and DL implants were 63 and 57, respectively. One month after implant placement, the mean ISQ value for PL implants was 73.

Two months after implant placement, the mean ISQ value for PL implants was 75. Three months after implant placement, the mean ISQ values for PL and DL implants were 76 and 69, respectively. Six months after implant placement, the mean ISQ values for PL and DL implants were 79 and 76, respectively.

Conclusion:

Despite its limitations, this pilot study indicated that compared to DL, PL can enhance bone density and implant stability, resulting in greater early functionality and fewer surgery sessions.