Intra- and inter-examiner agreement when assessing radiographic implant bone levels: Differences related to brightness, accuracy, participant demographics and implant characteristics

Single-piece zirconia versus single-piece titanium, narrow-diameter dental implants in the anterior maxilla: 5-year post-loading results of a randomized clinical trial

OBJECTIVES

The aim of this study was to evaluate esthetic parameters in the anterior maxillary region by comparing single-piece zirconia versus titanium narrow-diameter implants. Additionally, clinical, radiological and patient-reported outcome measures (PROMs) were analyzed.

MATERIALS AND METHODS

Thirty implants (tissue level implant) were placed in 30 patients in the maxillary esthetic sector. Depending on randomization, a zirconia (test) or titanium implant (control) was placed. Esthetic, clinical, and radiological parameters, including the implant crown esthetic index (ICAI), pink esthetic score (PES), probing pocket depth, bleeding on probing, plaque index, and marginal bone levels, were evaluated at 12, 36 and 60 months after loading.

RESULTS

Sixty months after crown placement, no significant differences were found between groups. The ICAI values were 5.25 ± 4.21 and 4.50 ± 2.98 for the test and control groups, respectively. The corresponding PES values were 7.44 ± 1.93 and 7.43 ± 1.74 for the test and control groups, respectively. There were no significant intergroup differences for the rest of the parameters evaluated.

CONCLUSION

It can be suggested that monotype zirconia implants may serve as a potential alternative to titanium implants in selected clinical scenarios. While the results demonstrated comparable esthetic, clinical, and radiological aspects for zirconia implants as compared to titanium implants after a 5-year follow-up period, further research with larger sample sizes and longer-term follow-up is recommended.

Clinical outcome of monolithic zirconia on bonded or mechanically retained prefabricated titanium-base: A 4-year retrospective study

OBJECTIVE

To assess the clinical performance of monolithic screw-retained implant-supported zirconia crowns (MSI) bonded or mechanically retained on prefabricated Ti-bases using a complete digital workflow.

METHODS

A retrospective analysis was conducted on patients who underwent single dental implant procedures between January 2017 and May 2018. Inclusion criteria were: patients over 18 years of age; implants placed in posterior sites; MSI on prefabricated Ti-base realized by using a complete digital workflow; a minimum follow-up period of 2 years. Cemented crowns and fixed dental prosthesis were excluded. Mechanical complications included: fracture of Ti-base; loss of retention; loosening of Ti-base screws. Technical complications included: fracture and debonding of monolithic zirconia. Biological complication was set strictly at a probing pocket depth of 5 mm and bleeding on probing or pus secretion.

RESULTS

A total of 144 dental implants placed in 127 patients were included, 73 with a fully tapered implant system (BLX) and 71 with a conical connection system (Nobel Parallel CC). Of the 73 BLX implants, 4 experienced loosening of the Ti-base screw, while 3 Nobel Parallel CC implants experienced the same problem. In addition, 4 fractures of the Ti-base and 6 fractures of the inner surface of the monolithic zirconia were observed in the Nobel Parallel CC implants. Cumulative survival was 100 % for bonded crowns and 85 % for mechanically retained crowns. Radiographic evaluation revealed a mean CBL of 0.12 mm for the BLX and 0.13 mm for the Nobel Parallel CC implants with no statistically significant differences between the Ti-base types. There was no evidence of bleeding on probing or pus secretion. All probing pocket depths were <3 mm.

CONCLUSION

The use of a prefabricated Ti-base remains a clinically acceptable choice, however, MSIs bonded to prefabricated Ti-bases had fewer mechanical and technical complications than the MSI mechanically retained to a prefabricated Ti-base.

Inter and intra-operator reliability of Lekholm and Zarb classification and proposal of a novel radiomic data-driven clustering for qualitative assessment of edentulous alveolar ridges

OBJECTIVES

The present study was conducted to evaluate the reproducibility of Lekholm and Zarb classification system (L&Z) for bone quality assessment of edentulous alveolar ridges and to investigate the potential of a data-driven approach for bone quality classification.

MATERIALS AND METHODS

Twenty-six expert clinicians were asked to classify 110 CBCT cross-sections according to L&Z classification (T0). The same evaluation was repeated after one month with the images put in a different order (T1). Intra- and inter-examiner agreement analyses were performed using Cohen's kappa coefficient (CK) and Fleiss' kappa coefficient (FK), respectively. Additionally, radiomic features extraction was performed from 3D edentulous ridge blocks derived from the same 110 CBCTs, and unsupervised clustering using 3 different clustering methods was used to identify patterns in the obtained data.

RESULTS

Intra-examiner agreement between T0 and T1 was weak (CK 0.515). Inter-examiner agreement at both time points was minimal (FK at T0: 0.273; FK at T1: 0.243). The three different unsupervised clustering methods based on radiomic features aggregated the 110 CBCTs in three groups in the same way.

CONCLUSIONS

The results showed low agreement among clinicians when using L&Z classification, indicating that the system may not be as reliable as previously thought. The present study suggests the possible application of a reproducible data-driven approach based on radiomics for the classification of edentulous alveolar ridges, with potential implications for improving clinical outcomes. Further research is needed to determine the clinical significance of these findings and to develop more standardized and accurate methods for assessing bone quality of edentulous alveolar ridges.

Root-analogue implants compared to forced orthodontic extrusion: a retrospective analysis of clinical, radiological and esthetic outcomes after restoration

OBJECTIVES

To assess clinical, radiological and esthetic outcomes of restorations supported by root-analogue implants (RAIs) or roots of severely damaged teeth after forced orthodontic extrusion (FOE).

MATERIALS AND METHODS

Clinical data regarding milled one-piece (titanium/zirconia roots and zirconia abutments) RAIs (REPLICATE™ System) and FOE were recorded and retrospectively evaluated for 40 patients by two investigators. Strict inclusion and exclusion criteria were applied. Functional and esthetic outcomes were assessed for n = 20 pre-molars and n = 20 anterior teeth via comparison of radiographic and digital images applying the novel Functional Implant Prosthodontic Score (FIPS). Krippendorff's alpha coefficient was calculated to assess inter-rater reliability. Mann-Whitney-U-Test was used to compare the assessed parameters. Level of significance was set to p < 0.05.

RESULTS

After a mean observation period of 18.4 ± 5.7 months for restorations supported by RAIs and 43.9 ± 16.4 months for restorations after FOE, mean FIPS scores were 9.2/8.8 ± 1.1/1.2 (RAIs) and 7.4/7.7 ± 1.3/1.5 (FOE), respectively. Krippendorff's alpha coefficients did not reveal unacceptable inter-rater reliabilities regarding the investigators and applicability of FIPS. Significant differences were documented when comparing restorations after FOE or supported by RAIs regarding bone loss (p < 0.01), presence of papillae (p < 0.05) and quality and quantity of mucosa (p < 0.02) in favor of FOE.

CONCLUSIONS

Within the main limitations of sample size and the retrospective study design, both concepts seem to provide clinically acceptable results.

CLINICAL RELEVANCE

Bone- and tissue-preserving characteristics regarding the concept of FOE are promising. It could be applicable for socket preservation and subsequent conventional implant placements in an adapted workflow.

Marginal bone level changes around dental implants with one or two adjacent teeth - A clinical and radiographic retrospective study with a follow-up of at least 10 years

AIM

To compare mean bone level (mBL) changes around dental implants with one or two adjacent teeth after a function time of ≥10 years.

MATERIALS AND METHODS

One hundred thirty three periodontally compromised patients (PCPs) with 551 implants enrolled in supportive periodontal care (SPC) were screened. Implants were categorized either into group TIT (tooth-implant-tooth) or into group TIG (tooth-implant-gap). MBL changes from delivery of restoration (i.e., baseline) to follow-up were calculated in millimeters and compared between implants and adjacent teeth. Survival rates and the need for surgical interventions during SPC were recorded.

RESULTS

Eighty seven patients with 142 implants were re-evaluated after a mean observation time of 14.5 ± 3.5 years. The mBL at mesial implant sites in the TIT group increased -0.07 ± 0.92 mm and decreased in the TIG group 0.52 ± 1.34 mm, respectively (95% CI: 0.04/1.14, p = .037). At distal implant sites, the mBL in the TIT group increased -0.08 ± 0.84 mm and decreased 0.03 ± 0.87 in the TIG group, respectively (95% CI: -0.20/0.42, p = .48). The overall implant loss rate was 3.5% (n = 5; 2 TIT, 3 TIG), without a statistically significant difference between the two groups (95% CI: 0.18/7.07, p = .892). Tooth loss rates (TIT: 12.3%, TIG: 12.3%) were not statistically significantly different (OR = 1.00, p = .989).

CONCLUSION

High tooth and implant survival rates were observed in PCPs. The presence of one or two adjacent teeth seemed to have no impact on marginal bone level changes.

Clinical outcomes of dental implants in patients with and without history of periodontitis: A 20-year prospective study

AIM

To present the 20-year clinical outcomes of tissue-level implants in partially edentulous patients previously treated for periodontitis and in periodontally healthy patients (PHP).

MATERIAL AND METHODS

The original population consisted of 149 partially edentulous patients consecutively enrolled in a private specialist practice and divided into three groups: PHP, moderately periodontally compromised patients (mPCP) and severely PCP (sPCP). After successful completion of periodontal/implant therapy, patients were enrolled in an individualized supportive periodontal care (SPC) programme.

RESULTS

Eighty-four patients rehabilitated with 172 implants reached the 20-year examination. During the observation time, 12 implants were removed (i.e., 11 due to biological complications and 1 due to implant fracture), leading to an overall implant survival rate of 93% (i.e., 94.9% for PHP, 91.8% for mPCP and 93.1% for sPCP [p = .29]). At 20 years, PCP compliant with SPC did not present with significantly higher odds of implant loss compared with PHP compliant with SPC (p &gt; .05). Conversely, PCP not compliant with SPC experienced implant loss with odds ratio of 14.59 (1.30-164.29, p = .03).

CONCLUSIONS

Tissue-level implants, placed after comprehensive periodontal therapy and SPC, yield favourable long-term results. However, patients with a history of periodontitis and non-compliant with SPC are at higher risk of biological complications and implant loss.

Short strategic implants for mandibular removable partial dentures: One-year results from a pilot randomized crossover abutment type study

Objectives

The present pilot study analyzed two abutment types (a retentive ball and a non‐retentive dome) in implant‐assisted removable partial dentures (IARPDs) on 6 mm short implants with respect to clinical, radiological, and patient‐reported outcomes (PROs), during the first year.

Materials and Methods

Two implants were placed bilaterally in mandibular molar sites, converting existing free‐end removable partial dentures (RPDs) to IARPDs. Twelve subjects were randomized to initially receive either the dome (Group A, n = 6) or the ball abutment (Group B, n = 6). After eight weeks, the abutments were exchanged. After another 8 weeks, the participants were given the choice of one of the abutments. Mean values and standard deviations (SD) were calculated, and random‐effect linear regression analyses were applied to analyze marginal bone level alterations and PROs (α < .05).

Results

Twelve participants were included in the study; however, one dropout occurred. Patient ratings increased significantly in both study groups. The majority of the participants (82%) ultimately chose the ball abutment. The implant survival rate was 100%, and the success rate was 90.9% twelve months after implant placement (mean peri‐implant bone‐loss: −1.2; SD: 0.6 mm) without a statistically significant difference between the study groups, in terms of clinical‐ and radiological outcomes.

Conclusion

Placing 6 mm short implants at mandibular molar sites of RPD wearers seems to be a viable treatment option, based on this investigation with a short‐term follow‐up. Although only minor differences between the two abutments were observed, patients seem to prefer the ball over the dome abutment.

Clinical performance of posterior monolithic zirconia implant-supported fixed dental prostheses with angulated screw channels: A 3-year prospective cohort study

STATEMENT OF PROBLEM

The choice of retention type of an implant-supported fixed dental prosthesis (FDP) becomes critical when the dental implant is not placed in a prosthetically ideal location. In recent years, computer-aided design and computer-aided manufacturing (CAD-CAM) technology has enabled the correction of the location of screw access hole depending on the clinical needs of the patient. However, how FPDs with angulated screw channels (ASCs) perform clinically is unclear.

PURPOSE

The purpose of this prospective clinical study was to evaluate the mechanical complications and crestal bone loss (CBL) when posterior monolithic zirconia implant-supported FDPs with an ASC are used.

MATERIAL AND METHODS

Participants (N=37) with a missing single posterior tooth or multiple teeth, sufficient bone height, and an implant site without infection were included. Each participant received parallel-walled implants (Nobel Parallel CC) of 7-, 8.5-, or 10-mm length by using a 1-stage approach. After 4 months of healing, a conventional impression was made, and a digital workflow was followed. Monolithic zirconia restorations (Katana ML) were milled, stained, and mechanically attached to a titanium base (NobelProcera ASC abutment). CBL was measured from radiographs at 6, 12, 24, and 36 months after the placement of the prosthesis. Implant and prosthetic characteristics including implant diameter, implant length, screw channel angle (angle≤15 degrees versus angle>16 degrees), prosthetic type (single crown versus multiple-unit FDP), and antagonist dentition (natural versus prosthesis) were also recorded. A generalized linear mixed model with a log link was estimated to assess the independent predictors of CBL among the angles of ASC-retained definitive restorations and the clinically relevant variables (α=.05).

RESULTS

Thirty-seven participants received 51 implants, and the median follow-up period was 30 months (interquartile range: 22-36). Two single-crown implants failed within the first 12 months of delivery. The implant and restoration survival rate was 96% at 36 months. Screw loosening was recorded in 2 study participants. After a follow-up of 36 months, the mean ±standard deviation CBL value was 0.15 ±0.14 mm with an increase over time (P<.001). The effect of the angle of ASC, implant diameter, implant length, prosthetic type, and antagonist on the CBL was not statistically significant (P>.05).

CONCLUSIONS

CBL was not associated with the angle of ASC, implant diameter, implant length, prosthetic type, or antagonist when posterior monolithic zirconia implant-supported FDPs with ASCs were used. Screw loosening in 2 situations was the only mechanical complication during the first 3 years of service.

Marginal bone loss and the risk indicators of fixed screw-retained implant-supported prostheses and fixed telescopic-retained implant-supported prostheses in full arch: A retrospective case-control study

OBJECTIVES

This study compared full-arch screw-retained implant-supported fixed dental prostheses (FSI-FDPs) and full-arch telescopic-retained implant-supported fixed dental prostheses with a professional retrieval system (FTI-FDPs) on marginal bone loss (MBL), the risk indicators and peri-implantitis rate after 7-13 years.

MATERIAL AND METHODS

Sixty five edentulous patients were treated with 86 prostheses and 592 implants. The FSI-FDP group comprised 26 patients (32 prostheses, 202 implants), and the FTI-FDP group comprised 39 patients (54 prostheses, 390 implants). MBL and the risk indicators of MBL ≥1 mm were assessed. Peri-implantitis rates at 13 years were also calculated.

RESULTS

Full-arch screw-retained implant-supported fixed dental prostheses and FTI-FDP implants exhibited comparable mean MBLs of 0.60 ± 0.51 and 0.41 ± 1.03 mm, respectively. MBL ≥1 mm was noted for 25% of FSI-FDP implants and 6.9% of FTI-FDP implants. Superstructure-abutment connection (screw retention:FSI-FDPs >telescopic retention:FTI-FDPs) and implant-abutment connection (External butt joint, Internal butt joint >Morse taper joint) were associated with MBL ≥1 mm. Peri-implantitis rates at the implant level were 3.99% (95%CI = 3.93-20.5) in FSI-FDP group and 3.85% (95%CI = 3.85-34.3) in FTI-FDP group with no significance.

CONCLUSIONS

It was concluded that FSI-FDP and FTI-FDP implants exhibited comparable MBL; however, the risk of MBL ≥1 mm in FTI-FDPs was lower than in FSI-FDPs. Besides, implant-abutment connection was the risk indicator of MBL ≥1 mm. In peri-implantitis rate, FSI-FDPs and FTI-FDPs behave similarly.

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

Background

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

Material and Methods

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

Results

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

Conclusions

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

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

Intra- and inter-observer agreements in detecting peri-implant bone defects between periapical radiography and cone beam computed tomography: A clinical study

Background/purpose

Information regarding agreements between periapical radiograph (PA) and cone beam computed tomography (CBCT) in detecting peri-implant defect is still scarce. The aim of this clinical study was to compare agreements between PA and CBCT in detecting peri-implant bone defect.

Materials and methods

This retrospective clinical study enrolled 32 patients with both PA and CBCT filmed right after implant placement. Four modalities were used for film reading: PA1 (original), PA2 (enhanced brightness/contrast), CBCT1 (selected axial and mesial-distal direction images) and CBCT2 (all data with software). 2 experienced and 2 inexperienced observers scored all films. Intra- and inter-observer agreements were estimated with Cohen's kappa coefficient. Categorized agreements were compared and differences among four modalities were calculated.

Results

Agreements of PA were better than CBCT when detecting peri-implant bone defects in inter-observer agreements (median kappa 0.471 vs. 0.192; p = 0.016). Moreover, agreements in experienced observers were better than inexperienced observers (median kappa 0.883 vs. 0.567; p < 0.001). There was significant difference among four modalities except for experienced observer 2 (p = 0.218).

Conclusion

Agreements of PA are better than CBCT when detecting peri-implant bone defects, especially for inter-observer agreements. Experienced observers are more consistent in assessment than inexperienced ones.

Clinical Outcomes of Root-Analogue Implants Restored with Single Crowns or Fixed Dental Prostheses: A Retrospective Case Series

The objective was to investigate clinical and radiological outcomes of rehabilitations with root-analogue implants (RAIs). Patients restored with RAIs, supporting single crowns or fixed dental prostheses, were recruited for follow-up examinations. Besides clinical and esthetical evaluations, X-rays were taken and compared with the records. Patients were asked to evaluate the treatment using Visual Analogue Scales (VAS). For statistical analyses, mixed linear models were used. A total of 107 RAIs were installed in one dental office. Of these, 31 were available for follow-up examinations. For those remaining, survival has been verified via phone. RAIs were loaded after a mean healing time of 6.6 ± 2.5 months. 12.1 ± 6.9 months after loading, a mean marginal bone loss (MBL) of 1.20 ± 0.73 mm was measured. Progression of MBL significantly decreased after loading (p = 0.013). The mean pink and white esthetic score (PES/WES) was 15.35 ± 2.33 at follow-up. A survival rate of 94.4% was calculated after a mean follow-up of 18.9 ± 2.4 months after surgery. Immediate installation of RAIs does not seem to reduce MBL, as known from the literature regarding screw-type implants, and might not be recommended for daily routine. Nevertheless, they deliver esthetically satisfying results.

Implant loss and crestal bone loss in immediate versus delayed load in edentulous mandibles: A systematic review and meta-analysis

STATEMENT OF PROBLEM

The current trend is to shorten the loading times of dental implants. However, information about the risk of early loss of implants that have been loaded immediately is scant if compared with data available for those conventionally loaded.

PURPOSE

The purpose of this systematic review and meta-analysis was to study immediate (IL) and delayed loading (DL) protocols in edentulous mandibles to determine whether differences exist in implant success and crestal bone loss and to evaluate these possible differences in relation to the type of prosthesis and the splinting of the implants.

MATERIAL AND METHODS

The literature review was conducted in PubMed, Scopus, and the Cochrane Library. Nine randomized clinical trials were included.

RESULTS

The result of a meta-analysis of implant loss before 1 year was 2.63 (95% CI: 1.22, 5.68), favoring the DL control group, while the outcome for crestal bone loss at the observation year was 0.42 (95% CI: -0.35, 1.20), with a tendency toward reduced bone loss for DL.

CONCLUSIONS

The risk of early loss in the IL group was higher than that in the DL group. For removable prostheses and nonsplinted implants, DL was preferred. The quality of scientific evidence significantly favors DL.

Zirconia implants restored with single crowns or fixed dental prostheses: 5-year results of a prospective cohort investigation

AIM

To evaluate the clinical and radiological outcomes of one-piece zirconia implants restored with single crowns (SCs) or fixed dental prostheses (FDPs) over an observation period of 5 years in function.

MATERIALS AND METHODS

In a prospective cohort investigation with two investigational centers, one-piece zirconia implants were placed in anterior and posterior sites. After a healing period of at least 2 months in the mandible and 4 months in the maxilla with immediate provisional reconstructions, the final all-ceramic SCs or three-unit FDPs were cemented. Patients were followed for 5 years. Clinical parameters and radiological measurements of the implants and the neighboring teeth were assessed. For the statistical analysis, linear mixed models were applied.

RESULTS

A total of 71 implants were placed in 60 patients. Sixty-three implants in 53 patients could be evaluated at the 5-year follow-up. Six patients with a total of seven implants were counted as dropouts. One implant did not achieve adequate osseointegration and had to be removed 5 weeks after implantation. The 5-year survival rate was calculated as 98.4% (95% CI 91.6, 99.9). The mean overall marginal bone loss from implant placement to the 5-year follow-up was 0.7 ± 0.6 mm. After an initial mean marginal loss before loading the implants (0.7 mm), no further statistically significant change in marginal bone level (p = .458) could be observed.

CONCLUSION

The investigated one-piece zirconia implant showed a high survival rate, very stable marginal bone, and mucosal margin levels after 5 years in function. Therefore, it can be considered safe and reliable for the reconstruction of implant-supported SCs or FDPs over a mid-term period.

Factors influencing long-term survival rates of implants placed simultaneously with lateral maxillary sinus floor augmentation: A 6- to 20-year retrospective study

OBJECTIVES

To evaluate the long-term influence of residual bone height (RBH), sinus membrane perforation and the presence of voids on the survival of implants placed simultaneously with lateral maxillary sinus floor augmentation (MSFA).

MATERIALS AND METHODS

A total of 207 patients (613 implants) who underwent MSFA from 1999 to 2003 and followed up until 2018 were included in this study. RBH and marginal bone loss were assessed using a series of panoramic and periapical radiographs. Cumulative survival rates (CSR) with log-rank tests and hazard ratios of implant failure according to RBH, membrane perforation, and the presence of voids were assessed.

RESULTS

The overall 10-year and 20-year CSRs were 95% (95% CI: 84.95%-85.05%) and 85% (95% CI: 84.95%-85.05%), respectively. CSR was significantly higher for implants with ≥3 mm RBH (n = 260, 92.4%) than those with <3 mm RBH (n = 353, 78.8%) (p = .002). CSR of non-smoking group (n = 312, 90.0%) was higher than that of smoking group (n = 301, 77.1%) (p = .009). There was no significant difference in the hazard ratio of implant failure between the perforated membrane group (n = 245) and the non-perforated group (n = 368). In two out of 11 patients with voids, the inflammation of peri-implantitis progressed into voids, resulting in severe bone resorption.

CONCLUSIONS

The survival of implants placed in <3 mm of RBH, even though it showed a lower CSR, could be considered acceptable. Neither sinus membrane perforation nor the presence of voids appeared to affect implant survival as long as supportive maintenance therapy with proper oral hygiene was provided.