International Journal of Implant Dentistry最新文献

Purpose: To compare cone-beam computed tomography (CBCT) with photon-counting detector computed tomography (PCD-CT) at equivalent radiation doses, focusing on qualitative and quantitative parameters relevant to dental implant surgery.

Methods: This ex vivo comparative study of porcine specimens assessed five imaging protocols with both CBCT and PCD-CT at three effective radiation dose levels (high: 360µSv, standard: 145µSv, low: 20µSv) to evaluate image quality, artifact burden, metal artifact susceptibility, and quantitative bone measurements in the mandibular region. Three blinded readers analyzed the data using a 5-point Likert scale (5 = highest to 1 = lowest rating) and performed linear bone measurements at implant planning sites. Statistical analysis included descriptive statistics and inter-reader reliability assessment using intraclass correlation coefficients (ICC).

Results: Each reader evaluated 30 data sets (12 CBCT, 18 PCD-CT), with 24 implant planning sites per imaging protocol. High-dose PCD-CT demonstrated the best image quality and diagnostic interpretability (4.89 ± 0.27), followed by standard-dose PCD-CT and CBCT (4.50 ± 0.73; 4.33 ± 0.61), with low-dose protocols showing intermediate quality with higher artifact burden. In comparison to CBCT, PCD-CT demonstrated superior performance in reducing implant-induced artifacts across all protocols. Quantitative bone measurements showed minimal variability, meeting clinical precision requirements for computer-assisted implant surgery. Both qualitative (ICCs:0.70-0.89; p < 0.001) and quantitative (ICCs:0.79-1; p < 0.001) analyses demonstrated high reliability, regardless of the reader's experience.

Conclusions: PCD-CT demonstrated superior image quality and reduced artifacts compared with CBCT at all radiation dose levels. These findings highlight PCD-CT's potential to enhance implant planning and improve clinical outcomes with reduced radiation exposure while maintaining diagnostic accuracy.

Objectives: To retrospectively assess the potential impact of biological and host factors on radiographic bone loss following tissue-level implant placement and prosthetic rehabilitation.

Methods: The University database was reviewed to identify patients treated with tissue-level implants between 2006 and 2020 at the University of Zurich, Switzerland. The study included patients who received screw-retained implant rehabilitations in the posterior area without simultaneous hard- or soft-tissue augmentations and had a follow-up period of at least 12 months. Radiographic measures of marginal bone loss and supracrestal tissue height were conducted using periapical x-rays at different time points. Additional factors analysed included age, gender, smoking status, history of periodontitis, jaw of treatment, type of reconstruction, and prosthetic emergence angle. Associations between marginal bone loss and potential explanatory variables were visualised and analysed. Elastic net regressions were applied to examine potential relationships with marginal bone loss.

Results: A total of 1,479 patients were treated with tissue-level implants. After applying inclusion and exclusion criteria, 106 patients with 106 implants were included in the statistical evaluation after one year (T1, n = 106 implants), and 59 patients with 59 implants were evaluated after three years (T2, n = 59 implants). The mean marginal bone loss was 0.93 mm (SD 0.83) at T1 and 1.04 mm (SD 0.97) at T2. A strong correlation (Spearman) was found between mesial and distal bone loss. Smoking status and the jaw undergoing treatment were associated with bone loss. While these associations were observed in the univariate analysis, a more comprehensive multivariate analysis revealed that these variables had a limited effect on explaining radiographic bone loss.

Conclusions: During the initial rehabilitation period in tissue-level implants in this cohort smoking status and jaw of treatment seemed to influence early peri-implant bone loss. Further, a strong correlation between mesial and distal MBL was observed. Additional research is required to determine factors contributing to early bone loss following implant-prosthetic rehabilitation.

Purpose: This study assessed the impact of the buccal bone on hard and soft tissues in submerged and non-submerged immediate implants using a minipig model.

Methods: Sixty-five titanium implants (Camlog Progressive Line) were placed in four minipigs immediately after tooth extraction. All non-submerged (NSM) implants received a mechanically induced buccal bone defect (NSM-BD), whereas the submerged group (SM) was classified as defective (SM-BD) and intact (SM-BI). All bone defects underwent guided bone regeneration (GBR). After four months, the minipigs were sacrificed. Harvested specimens were analysed using histomorphometry and light and fluorescence microscopy. The evaluated parameters included the sulcus (S), implant epithelium (IE), connective tissue (CT), biological width (BW), highest soft tissue point (HSTP), and first hard tissue contact (FHTC).

Results: Of the 65 implants four (6%) were lost, while all remaining implants demonstrated clinical stability (Periotest). Despite GBR failures caused by the pigs' hay consumption after one week, no significant differences (p > 0.5) were observed between SM-BD and NSM-BD in buccal parameters (NSM-BD/SM-BD: S = 0.6 mm, IE = 2.9/2.4 mm, CT = 3.5/3.4 mm, BW = 5.9/5.8 mm). Compared to SM-BI soft-tissue parameters increased in length with reduced buccal bone lamella (SM-BI/SM-BD: S = 0.4/0,6 mm; p ≤ 0.04, SM-BI/NSM-BD: IE = 1.8/2.9 mm; p ≤ 0.007, SM-BI/SM-BD: CT = 2.5/3.4 mm; p ≤ 0.01, BW = 4.0/5.8 mm; p ≤ 0.007). The buccal HSTP remained unaffected (p > 0.5; (NSM-BD = 1.8 mm, SM-BD = 1.0 mm, SM-BI = 2.0 mm; p > 0.5) for all groups.

Conclusion: A buccal bone defect resulted in prolonged S, IE, CT, and BW. However, the aesthetic parameter HSTP did not exhibit significant differences (p > 0.5) at the buccal implant site when comparing the SM and NSM healing protocols.

Background: Implant therapy in the advanced atrophic jaw remains challenging in oral and maxillofacial surgery. Hence, a plethora of different augmentation procedures to increase bone volume in the maxilla and mandible have been published. Horizontal vascular-stalked split osteotomy (HVSO) represents a safe and effective approach for the three-dimensional jaw augmentation since it combines maximum vascularization through lingual or palatinal periosteal stalking with reduced grafting morbidity.

Objective: To analyze the efficacy of HVSO for implantation therapy in atrophic jaws by assessing vertical bone gain and implant survival rates.

Materials and methods: A total of n = 29 patients (14 females, 15 males) with a mean age of 55.4 ± 10.0 years and reduced volume of the alveolar ridge were retrospectively analyzed after treatment with 34 HVSOs in the maxilla and mandible. After controlled clinical follow-up of six months after augmentation, enossal implantation of 79 implants (maxilla 45, mandible 34) was performed. A standardized two-dimensional radiological assessment with panoramic tomography (OPTG) of the augmented bone height and clinical evaluation of the implants was performed over a mean follow-up period of 2.3 years.

Results: HVSO resulted in a significant increase in vertical bone height by 4.4 mm ± 2.0 mm (mean vertical gain: +59.4%) with + 101% in the maxilla and + 27.5% in the mandible directly after the procedure (T1), with both p < 0.001. After a mean observation period of 2.3 years bone height remained stable with a total gain of 41.4% (maxilla: 72.6%, mandible: 18.6%), with p < 0.001 and p = 0.001, respectively. Overall implant survival rate was 91% (maxilla: 89%; mandible: 94%).

Conclusion: HVSO reliably supports significantly enhanced vertical bone height with long-term stable results, thereby facilitating successful implantation in atrophic jaws with high implant survival rates observed over an extended follow-up period.

Clinical trial number: Not applicable as the study was no clinical trial.

Purpose: The primary aim of this in vitro study was to investigate the primary implant stability obtained in immediate and late implant placement scenarios. Secondary aims evaluated the effect of two distinct implant macro-designs and examined the correlation between resonance frequency analysis (RFA) and final insertion torque.

Methods: Partially edentulous maxillary models including six single sites simulating extraction sockets and healed alveolar ridges were used. Virtual implant planning facilitated static computer-assisted implant placement of bone level implants with either a shallow-threaded and cylindrical (BL), or deep-threaded and tapered implant macro-design (BLX). The insertion torque was continuously measured during implant placement, and RFA was performed after final implant positioning.

Results: One-hundred and forty-four implants were equally distributed to two alveolar ridge morphologies and implant designs. Higher final insertion torque and RFA values were observed for implants placed in healed ridges compared to extraction sockets (40.8 ± 13.5 vs. 20.6 ± 8.4 Ncm, and RFA 70.7 ± 2.8 vs. 59.6 ± 6.5, both p < 0.001), and for BL implants compared to BLX implants (35.7 ± 13.0 vs. 25.7 ± 8.9 Ncm, and RFA 66.7 ± 4.4 vs. 63.6 ± 4.9, both p < 0.001). Insertion torque and mean RFA values positively correlated (r = 0.742; p < 0.001).

Conclusion: Primary implant stability is significantly affected by the alveolar ridge morphology and the implant macro-design, demonstrating higher values in healed sites and shallow-threaded, cylindrical implants. Therefore, a tailored selection of the implant design depending on the implant placement and loading protocol is recommended.

Purpose: The aim of this retrospective study was to investigate and compare the effects of platform switching (PS) and platform matching (PM) on marginal bone loss (MBL) and clinical parameters in immediately inserted dental implants.

Methods: Thirty-seven patients were included (PS group: twenty-one patients, PM group: sixteen patients), with follow-up periods ranging from six months to 23 years. MBL was measured using orthopantomograms (OPG), and implant success was evaluated using the Buser, Albrektsson, and Attia criteria. Regression analysis was conducted to assess total bone loss.

Results: The BEGO RI implant system was used in 83.8% of cases. Mesial MBL averaged 0.26 mm in the PS group and 0.75 mm in the PM group, while distal MBL was 0.68 mm for the PS group and 0.53 mm for the PM group. A significant difference was observed in mesial MBL, with the PS group showing less bone loss (p. = 0.044). Regression analysis indicated that PM implants were associated with significantly greater mesial bone loss compared to PS implants (p. = 0.039). No significant differences in implant success were observed between the PS and PM groups based on the Buser score, Albrektsson criteria, and Attia score.

Conclusion: Both PS and PM implants showed comparable long-term functionality. No significant differences were found in total bone loss between the groups, but PS implants showed significantly lower mesial MBL. While both systems are viable for immediate implantation, PS implants may offer advantages in preserving peri-implant bone. Further prospective studies are needed to validate these findings.

Background: A case of postoperative mandibular defects was successfully managed using an intraoral scanner and computer-aided design/computer-aided manufacturing (CAD/CAM) technology, facilitating jaw reconstruction and functional restoration with implants for a critical mandibular defect.

Case presentation: The intraoral scanner was used to scan the maxilla and mandible, and occlusal scans were acquired. The obtained data were imported to CAD/CAM software to design the virtual teeth. Digital Imaging and Communications in Medicine data of preoperative cone-beam computed tomography images were converted to three-dimensional (3D) data using specialized software to examine the mandibular bone volume and modify the jawbone morphology. All data were superimposed on the implant simulation software, and jawbone morphology was modified considering the implant placement position. The finalized jawbone 3D data were printed using a 3D printer. Then, a titanium mesh tray was fabricated on the 3D printed model. Subsequently, iliac cancellous bone grafting using a titanium mesh tray and implant treatment were performed.

Conclusions: The application of digital technology helped visualize the final image of the treatment result and collaborate closely with the oral surgeon from the pre-reconstruction stage. This technique allows mandible reconstruction after considering the implant placement based on the ideal prosthesis.

Purpose: Silk fibroin (SF) is a biomaterial derived from the cocoon of the mulberry silkworm. This study aimed to assess the capacity of SF matrices biologized with injectable platelet-rich fibrin (iPRF) or enamel matrix protein (EMP) to modulate angiogenesis and immune response in the chorioallantoic membrane (CAM) assay.

Methods: 300 eggs were divided into the following groups: CM + NaCl, CM + iPRF, CM + EMP, SF + NaCl, SF + iPRF, and SF + EMP. Matrices were applied to the CAM on embryonic development day (EDD) 7 after rehydration. Angiogenesis, represented by vascularized area, vessel density, and vessel junctions, was evaluated on EDD 10, 12, and 14. Additionally, gene expression of HIF-1ɑ, VEGF, MMP-13, and NOS2 was assessed via quantitative polymerase chain reaction (qPCR) on EDD 11 and 14.

Results: The number of vascularized specimens was notably higher in SF matrices regardless of the treatment applied, while in the CM group, only matrices biofunctionalized with iPRF demonstrated vascularization. On EDD 14, the CM + iPRF group exhibited the highest values for total vascularized area (CM + iPRF: 57.52%, SF + iPRF: 21.87%, p < 0.001), vessel density (CM + iPRF: 0.0067 μm/µm², SF + iPRF: 0.0032 μm/µm², p = 0.002), number of vessel junctions (CM + iPRF: 14.45, SF + iPRF: 4.82, p = 0.001). Gene expressions displayed high data variability and no significant differences between the groups.

Conclusions: Biofunctionalization with iPRF in CM leads to a high vascularization rate probably through their capability of retaining higher liquid volumes, suggesting improved intraoral wound healing after guided tissue regeneration (GTR). Despite biofunctionalization, SF matrices exhibit a high vascularization, indicating SF as a promising material for GTR.

Peri-implantitis is known as an inflammatory condition affecting the soft and hard tissue around dental implants. A promising strategy to prevent these conditions is the use of antibacterial implants. This study aimed to evaluate the antibacterial potential of titanium (Ti) dental implants modified using plasma-electrolytic oxidation (PEO). The modified surfaces were subsequently loaded with silver (Ag) (n = 6) and zinc (Zn) (n = 6) ions and compared to unloaded Ti specimens (n = 6), with untreated specimens serving as controls. The specimens (each n = 5) were incubated in a culture medium containing a mixture of specific anaerobic bacterial strains. Scanning electron microscopy (SEM) was used to visualize the bacterial biofilm on each specimen. In addition, total bacterial deoxxyribonucleic acid (DNA) and the number of viable bacteria were determined using quantitative real-time polymerase chain reaction (qrt-PCR) and colony forming unit analysis (CFU), respectively. The results of the CFU analysis showed a 2 log (99%) reduction in viable bacteria in the samples loaded with Ag and Zn compared to the unloaded control group (p < 0.05). Moreover, significantly lower bacterial DNA counts were detected with a 5 log reduction (99.999%) in the Ag and Zn samples compared to the positive control group (bacterial mixed culture solution, p < 0.05). Therefore, it was considered that Ag and Zn loaded Ti implants may be a promising addition to current approaches to enable advanced antibacterial dental implants. However, further studies should be conducted to evaluate the in vivo cytocompatibility of the developed specimens.