This randomized clinical trial aimed to evaluate implant stability following graftless lateral window and crestal implant approaches for maxillary sinus floor elevation (MSFE) 1 year after implant placement.
Twenty-six single missing posterior maxillary teeth indicated for delayed implant placement, with a residual ridge height of 4–6 mm, were randomly assigned to perform either graftless lateral window (control) or crestal implant (test) approaches for MSFE. Implant stability was assessed using resonance frequency analysis; intra-sinus vertical bone gain and marginal bone loss were measured via CBCT 1 year after implant placement. Clinical parameters and patient-reported outcomes were also measured.
The reported implant stability quotient (ISQ) values were not significantly different between the lateral window and the crestal implant approaches (80.92 ± 4.57 and 80.19 ± 7.28, respectively) 12 months after implant placement. However, the lateral window approach revealed a significant increase (p < 0.001) in the mean ± SD intra-sinus vertical bone gain at 6 and 12 months (3.64 ± 0.84 mm and 3.82 ± 0.84 mm, respectively) compared to the crestal implant approach (1.66 ± 1.27 mm and 2.42 ± 1.39 mm, respectively). However, no intergroup significant difference was noticed concerning average marginal bone loss (p = 0.31) after 12 months. Postoperative complications and patient discomfort were more evident in the lateral window approach group.
In patients with a residual ridge height of 4–6 mm receiving implant therapy in conjunction with maxillary sinus elevation without graft material, there was no statistically significant difference in implant stability at 12 months between a lateral window and transcrestal sinus approach. Greater vertical bone gain was achieved following the lateral window approach.
This study aims to validate an existing risk assessment (RA) tool for predicting sinus membrane perforation (SMP) during the lateral-window sinus floor elevation (LSFE).
A multiple-center study was conducted in a hospital and university setting. Cone-beam computed tomography (CBCT) images and health records of patients who received LSFE from 2005 to 2021 were assessed. The effectiveness of the RA tool was evaluated on our dataset and additional analyses were performed to identify the key risk factors using logistic regression and the classification and regression trees (CART) methods.
A total of 126 sinuses in 113 patients were assessed, including 49 females and 64 males (60.1 ± 11.65 y/o). There were 24 SMP events in the study population. Patient-level and sinus-level analyses were consistent. The reduced logistic regression model suggested that the odds ratio (OR) of having an SMP event decreases by 23.7% with a 1 mm increase in residual bone height (RBH). Using a 3-mm RBH as the cut-off between “low risk” and “high risk,” rather than 4 mm as suggested in the original RA tool, provided better separation of SMP rates. CART analysis revealed that age may also be related to SMP risk.
In this exploratory study, RBH was the factor most correlated with SMP risk during LSFE, followed by age at the time of surgery. The critical thresholds for predicting SMP events were identified as 3.02 mm for RBH and 55.5 years of age. Within the inherent limitations, the current risk assessment tool could not be fully validated.
To evaluate the impact of the marginal fit of implant-supported prostheses (ISP) on peri-implant bone levels. Additionally, the study aimed to determine a clinically relevant threshold for the radiographic vertical misfit gap at the ISP, when present, and to identify potential risk factors associated with changes in bone levels.
This study involved subjects who received ISPs for tooth replacement therapy. Standardized intraoral periapical radiographs were taken 10 years after loading to assess the radiographic distance between the implant shoulder and the most coronal point of crestal bone (DIB). ISP marginal gaps were categorized as no gap or gap, with vertical dimensions categorized as 0 mm, > 0- < 0.1 mm, and ≥ 0.1 mm. A multivariable linear mixed-effect model was applied to control for potential confounders.
A total of 301 patients and 505 implants with a 10.6 ± 0.7 years follow-up were analyzed. ISPs without gaps exhibited statistically significantly lower DIB values (3.22 ± 0.8 mm) than those with gaps (3.43 ± 0.6 mm; p = 0.001). Gaps ≥ 0.1 mm were associated with statistically significantly higher DIB values (3.45 ± 0.7 mm; p = 0.001) compared with gaps between > 0 and < 0.1 mm (3.36 ± 0.5 mm; p = 0.001), or no gaps (3.22 ± 0.7 mm; p = 0.001). Each increment of 0.1 mm in the vertical crestal gap corresponded to a significant increase in DIB values (0.08 mm; p = 0.03). Finally, smoking and a history of periodontitis were independent risk factors for increased DIB.
Marginal misfit of ISP affects peri-implant bone stability, with gaps ≥ 0.1 mm linked to higher DIB. Smoking and periodontitis are independent risk factors for increased DIB.
The intention of this 10-year prospective cohort investigation was to clinically and radiographically investigate the outcomes of a one-piece zirconia implant system for single-tooth replacement.
A total of 65 patients received 66 single-tooth implants restored with all-ceramic crowns. Follow-up assessments were conducted at the time of prosthetic delivery, after 1, 3, 5, and 10 years. Peri-implant soft tissue parameters were evaluated. To assess peri-implant bone loss, standardized radiographs were taken at implant placement, prosthetic delivery, at the 1-, 3-, 5-, and 10-year follow-ups. Statistical analysis was conducted using linear mixed regression models and Wilcoxon Signed Rank tests to compare differences over time and between groups (p < 0.05).
Over the course of 10 years, 16 implants were lost, yielding a cumulative survival rate of 73.3%. Fifteen patients were lost to follow-up over the 10-year period. The average marginal bone loss of the remaining implants was 1.09 mm. Probing depth, attachment level, and bleeding showed an increase over time, while plaque index slightly decreased.
Given the high implant loss rate after 10 years and the high occurrence of advanced bone loss observed in this study, the implant was not recommended for routine clinical use.
To evaluate the survival and success rates of veneered zirconia-based single crowns (SCs) supported by zirconia implants in posterior regions, along with patient-reported outcomes, over 7.5 years.
Forty-five patients received zirconia implant-supported posterior SCs (n = 45) composed of zirconia frameworks layered with a leucite-reinforced feldspathic ceramic. At 7.5 years, clinical parameters and technical complications were assessed. Technical success was determined according to modified United States Public Health Service (USPHS) criteria. Patient-reported outcome measures (PROs) were evaluated using visual analog scales (VAS). Wilcoxon matched-pairs signed-rank test, mixed-effects ordered logistic regression, and linear mixed models analyzed time-dependent effects.
Thirty SCs (n = 30) could be evaluated at the 7.5-year follow-up (mean: 92.1 ± 3.4 months). Kaplan–Meier survival for SCs was 97.5% [95% CI: 83.6%–99.6%]. Success dropped to 79.4% [63.0%–89.2%] due to reconstructions with major chipping (n = 3), occlusal roughness (n = 7), marginal crevice (n = 1), and over-contouring (n = 2). PROs showed significant improvements from pre-treatment to delivery (VAS scores: 93%–97%) and remained stable throughout the follow-up period.
Veneered zirconia-based SCs supported by zirconia implants in posterior sites demonstrated high survival rates and consistently met patients' functional and esthetic expectations. Despite these favorable outcomes, the considerable incidence of technical complications warrants further investigation through long-term clinical studies.
While veneered zirconia crowns offer favorable esthetics, their susceptibility to chipping in posterior regions suggests that monolithic alternatives may be preferable. Further research is needed to optimize material selection and minimize technical complications.
While titanium has traditionally been the industry standard, zirconia presents superior physical and chemical properties that merit further investigation into its clinical efficacy. This study aims to examine the immunological responses associated with zirconia and titanium dental implants, emphasizing the potential advantages of zirconia as a viable alternative.
This study compares the immune responses to titanium and zirconia implants using a murine model, in which two implants were placed in the maxillary edentulous region for 7 days. Following this period, peri-implant tissue was harvested from 9 and 45 mice to assess myeloid immunity at both the transcriptomic and cellular levels, respectively.
Our findings indicate that zirconia implants exhibit superior biocompatibility compared to titanium implants, evidenced by transcriptomic data showing a minimal myeloid cell-mediated inflammatory response. Specifically, zirconia implants significantly reduce the infiltration and attachment of myeloid cells, particularly polymorphonuclear neutrophils. Additionally, zirconia implants prevent the polarization of macrophages to the inflammatory M1 phenotype, which is markedly heightened in titanium peri-implant tissues, promoting instead a shift toward the regenerative M2 phenotype.
These results suggest that zirconia implants can minimize inflammation and promote better healing. This experimental in vivo study provides evidence that zirconia implants offer a more biocompatible solution in the field of dental restoration compared to titanium.
To compare the efficacy of cross-linked volume-stable collagen matrix (VCMX) versus connective tissue graft (CTG) to increase buccal peri-implant mucosal thickness (MT) around dental implants.
The present is a parallel, randomized multi-center clinical trial, according to the CONSORT statement. Clinical centers were four Italian periodontal settings. All patients received a soft tissue augmentation procedure, by means of CTG or VCMX. The primary outcome variable was peri-implant mucosal thickness (MT) difference at 12 months follow-up. The statistical unit was the patient. An analysis of covariance was performed for this outcome variable. Secondary outcomes were patient-reported outcome measures (PROMs), complications, variability among operators, and changes in keratinized mucosa width (KMW).
A total of 98 patients completed the study, 49 in each group. MT increase was 1.0 ± 0.75 in the CTG group and 0.66 ± 0.58 mm in the VCMX group. CTG showed superior results to VCMX for MT gain (0.37 mm, 95% CI: 0.13–0.61, p = 0.002). In cases of Baseline MT ≥ 2 mm, CTG and VCMX yielded comparable results. VCMX was associated with shorter chair time (diff: 10.0 min; 95% CI: 5.02 to 14.98; p < 0.0001). Patients in the VCMX group experienced fewer days of discomfort (0.46 days, 95% CI: 0.06–0.99, p = 0.05), while no differences were found for final aesthetic and general satisfaction (CTG: 99.28 ± 2.28, VCMX: 98.48 ± 3.92, p = 0.22).
Both techniques improved MT, and CTG yielded better outcomes. VCMX was associated with shorter chair time and less postoperative discomfort, but both procedures achieved excellent final patient satisfaction.
This in vivo study aimed to evaluate the osseointegration of dental implants with a nanostructured hydroxyapatite (HAnano) coating or a double acid-etched (DAA) surface, grafted with or without calcium phosphate in the peri-implant gap, in low-density bone in a sheep model.
Thirty implants (15 HAnano and 15 DAA) were installed in the iliac crest of five sheep (2–4 years old). Six implants were placed per animal: two with a xenograft biomaterial, two with an alloplastic biomaterial, and two without grafting (control). Microtomographic analyses evaluated the percentage of bone and biomaterial for all groups. Histomorphometric analysis assessed bone-implant contact (BIC), bone occupied area fraction (BAFo), and biomaterial presence after an 8-week healing period. Data were analyzed using repeated-measures ANOVA or mixed-effects models with a significance level of 0.05.
No complications were observed during the healing period. The average BIC across all groups was 55%, ranging from 4.6% to 67.7%. BAFo averaged 30%, with biomaterial occupying 22% and connective tissue 44% of the interface area. There were no statistically significant differences between grafted and non-grafted groups for BIC (p = 0.413), BAFo (p = 0.097), connective tissue presence (p = 0.192), and for the percentage of bone and biomaterial (p = 0.959), bone percentage (p = 0.283), or biomaterial percentage (p > 0.0959).
Peri-implant grafting with xenograft or alloplastic biomaterials did not significantly enhance osseointegration compared to ungrafted implants in small peri-implant defects. These results suggest that spontaneous healing may suffice in such cases.
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