International Journal of Oral & Maxillofacial Implants最新文献

Purpose: To address the hypothesis that the tissue processing methods of solvent dehydration and freeze-drying would differentially affect the physicochemical characteristics of four commercially available bone allografts and the adhesion and differentiation of human bone marrow-derived mesenchymal stromal cells (hBMSCs) on such substrates in vitro. Materials and Methods: The surface morphology, surface area, and elemental composition of four commercially available cancellous bone allografts were examined using SEM, Brunauer-Emmett-Teller (BET) gas adsorption, and inductively coupled plasma (ICP) analyses. SEM was also employed to compare the allograft surfaces to that of human bone exposed by in vitro osteoclastic resorption. The allografts were seeded with hBMSCs, and the number of adhered cells was assessed at 3 and 7 days. Alkaline phosphatase (ALP) activity was quantified as a measure of osteogenic differentiation after 21 days. Results: Marked differences were seen between the physicochemical characteristics of the solvent-dehydrated and freeze-dried allografts, as well as between their resulting bone microarchitectures and that of osteoclast-resorbed human bone. Increased hBMSC adhesion and differentiation were observed on the solvent-dehydrated allografts compared to freeze-dried allografts, which suggests a higher putative osteogenic potential. The latter was attributed to better preservation of the bone collagen microarchitecture integrity, which may provide not only a more complex substrate architecture, but also a more favorable microenvironment to allow nutrients and oxygen to flow to the adhered cells. Conclusion: Commercially available cancellous bone allografts significantly differ in their physicochemical characteristics, stemming from differences in tissue processing and sterilization methods undertaken by tissue banks. These differences impact the response of MSCs in vitro and may alter the biologic performance of the grafts in vivo. Therefore, it is important to consider these characteristics when choosing a bone substitute for clinical application, as the physicochemical properties of the grafts play a crucial role in their interactions with the biologic environment and subsequent incorporation into the native bone.

Purpose: To evaluate the clinical outcomes of posterior implants with surveyed crowns in implant-assisted removable partial dentures (IARPDs). Materials and Methods: Internal-connection implants were inserted and restored with surveyed crowns at the most posterior molar regions of Kennedy class I or II in partially edentulous patients between 2007 and 2018. IARPDs were fabricated and functioned with or without clasps on the surveyed implant crowns. Clinical outcomes of biologic problems, mechanical problems, and marginal bone loss (MBL) through periapical and panoramic views were recorded and measured. The effects of sex, Kennedy classification, opposing dentition, and clasp existence on MBL were analyzed using Mann-Whitney test, and the implant length, crown-to-implant (C/I) ratio, and function period on MBL were analyzed using a multiple regression analysis at α = .05. Results: A total of 32 posterior implants were restored with a surveyed crown for IARPDs in 16 patients (7 men, 9 women; mean age: 69.3 ± 6.0 years). A total of 15 IARPDs were for the mandible (1 maxilla), and 13 were Kennedy class I (3 class II) before implant insertion. All internal-connection implants (15 bone-level and 17 tissue-level) with 7-mm (n = 12), 8.5-mm (n = 18), and 9-mm (n = 2) lengths were restored for 3 surveyed premolar crowns and 29 molar crowns (15 first molar and 14 second molar). The mean C/I ratio was 1.48. The mean function period of the implants was 60.9 ± 40.2 months (range: 14 to 155), and the mean MBL was 0.11 ± 0.36 mm. Only Kennedy class II showed significantly more MBL (P = .002). The implant survival and success rates were 96.9% and 90.6%, respectively. Conclusion: Within the limitations of this retrospective clinical study, mainly in mandibular IARPDs, implants with surveyed crowns showed high survival and success rates during short- to medium-term functions. Posterior implants with surveyed crowns appear to be a reliable alternative for free-end removable partial denture (RPD) patients.

Purpose: To investigate the effect of incisive papilla on esthetic ratings and lip support for patients who are treated with implant-supported fixed prostheses on edentulous maxillae. Materials and Methods: A study population of 118 patients with maxillomandibular edentulism was identified. A self-administered questionnaire was used to evaluate treatment outcomes through a patient perspective. Also, clinical factors such as smile line, maxillary resorption, incisive papilla position, and lip support were evaluated. Results: Lip support has a significant effect on the facial esthetic scores of patients, while smile line and incisive papilla localization have not had a proven statistically significant effect on esthetic and facial esthestic scores of patients treated with implant-supported fixed prostheses on maxillae. Conclusion: Although the patients were diagnosed with disadvantageous clinical factors such as crestally localized incisive papilla, they still noted higher esthetic scores with their fixed prostheses. Factors that affect the esthetic perception of patients or their priorities should be investigated more to understand the reasons for patient satisfaction with prostheses.

Purpose: To evaluate the effect of cooling on the reverse torque values of different abutments in bone-level and tissue-level implants. The null hypothesis was that there would be no difference in reverse torque values of abutment screws when cooled and uncooled implant abutments were compared. Materials and Methods: Bone-level and tissue-level implants (Straumann, each n = 36) were placed in synthetic bone blocks and subdivided into three groups (each n = 12) based on the abutment type (titanium base, cementable abutment, abutment for screw-retained restorations). All abutment screws were tightened to 35 Ncm torque. In half of the implants, a dry ice rod was applied on the abutments close to the implant-abutment connection for 60 seconds before untightening the abutment screw. The remaining implant-abutment pairs were not cooled. The maximum reverse torque values were recorded using a digital torque meter. The tightening and untightening procedure was repeated three times for each implant including cooling for the test groups, resulting in 18 reverse torque values per group. Two-way analysis of variance (ANOVA) was used to analyze the effect of cooling and abutment type on the measurements. Post hoc t tests were used to make group comparisons (α = .05). The P values of post hoc tests were corrected for multiple testing using the Bonferroni-Holm method. Results: The null hypothesis was rejected. Cooling and abutment type significantly affected the reverse torque values in bone-level implants (P = .004) but not in tissue-level implants (P = .051). The reverse torque values of bone-level implants significantly decreased after cooling (20.31 ± 2.55 Ncm vs 17.61 ± 2.49 Ncm). Overall mean reverse torque values were significantly higher in bone-level implants compared to tissue-level implants (18.96 ± 2.84 Ncm vs 16.13 ± 3.17 Ncm; P < .001). Conclusion: Cooling of the implant abutment led to a significant decrease in reverse torque values in bone-level implants and may therefore be recommended as a pretreatment before the application of procedures to remove a stuck implant part.

Purpose: To evaluate hard and soft tissue response and mechanical integrity for screw-retained layered zirconia crowns bonded to titanium nitride-coated titanium (TiN) CAD/CAM abutments supported by implants at 1- and 2-year follow-ups. Materials and Methods: A total of 46 patients were restored with a total of 102 free-standing implant-supported layered zirconia crowns, which were bonded to their respective abutments in the dental laboratory and delivered as a one-piece screw-retained crown. Baseline, 1-year, and 2-year data were collated on pocket probing depth, bleeding on probing, marginal bone levels, and mechanical complications. Results: Of the 46 patients, 4 patients with one implant each were not followed-up. These patients were not included in the analysis. Of the remaining 98 implants, due to failed appointments during the global pandemic, soft tissue measurements were recorded for 94 implants at year 1 and 86 implants at year 2, with a mean buccal/lingual pocket probing depth of 1.80/1.95 mm and 2.09/2.17 mm, respectively. Mean bleeding on probing was 0.50 and 0.53 at 1 and 2 years, which represents somewhere between no bleeding and a spot bleed according to the study protocol. Radiographic data were available for 74 implants at year 1 and 86 implants at year 2. The mean marginal bone change from baseline was +0.11 mm mesially and +0.19 mm distally at 1 year and +0.24 mm mesially and +0.16 mm distally at 2 years. The final bone level with respect to the reference point was +0.49 mm mesially and +0.19 mm distally at the end of the study period. Mechanical complications involving a slight misfit of the crown margin were recorded for one unit (1%), porcelain fracture for 16 units (16%), and a loss of preload for 12 units (12%) of < 5 Ncm (< 20% of initial preload). Conclusion: The biologic and mechanical stability of ceramic crowns bonded to CAD/CAM screw-retained abutments using angulated screw access was considered to be high, with overall bone gain, excellent soft tissue health, and only limited mechanical complications related to generally small fractures of the porcelain and a clinically insignificant loss of preload.

Purpose: To compare different assessment methods for peri-implant inflammation to evaluate potential risk factors and to generate a comprehensive algorithm for clinical staging, treatment, and evaluation of success in periorbital implants. Materials and Methods: In this hospital-based cross-sectional study, 111 periorbital implants in 40 patients with orbital defects after exenteration were clinically analyzed. Skin reaction according to Holgers (SRH), probing depth (PD) , and sulcus fluid flow rate (SFFR), as well as patient-specific data, such as age, sex, smoking and irradiation status, cleaning agent and frequency, defect etiology, implant system, implant location, time span since implantation, and type of retention, were assessed and statistically analyzed via mixed-model calculations. Success was defined as the absence of necessary invasive or antibiotic treatment. Results: A total of 62 implants (55.9%) had been placed in male patients and 49 implants (44.1%) in female patients. There were 18 patients (52 implants, 46.8%) who had received radiotherapy. Mean inflammation levels were low. PD and SFFR were highly correlated, whereby PD increased significantly with time after implantation. SRH ≥ 2 was correlated significantly with higher PD and SFFR values. While 80% of the implants did not require invasive or antibiotic treatment, 45% of the patients presented at least one affected implant. The data gathered allowed for the definition of a staging and treatment algorithm for peri-implantitis in periorbital implants. No patient-specific factors showed a significant impact on peri-implant inflammation. Conclusion: Periorbital implant restorations with magnetic abutments are a safe treatment option for orbital defects. PD and SRH were proven to be valuable quick assessment tools and should be complemented by SFFR, if inconclusive. The established parameters for the staging of peri-implant tissue health and clinical success can serve as a viable tool for reliable and comparable assessment in clinical and scientific settings. Further studies are necessary to assess the suggested treatment algorithm.

Purpose: To assess the accuracy of totally guided implant placement with static surgical splints in relation to the different types of supporting tissues (tooth, mucosa, or bone). Materials and Methods: This review was carried out following the PRISMA guidelines. An electronic search was done of the MEDLINE (PubMed), Embase, and Cochrane Library databases, without publication year or language restrictions. Results: The literature search yielded a total of 877 articles; 18 were included in the qualitative synthesis, and 16 of these articles were included in the quantitative analysis. The included studies presented a high risk of bias, except for one randomized clinical trial. The strength of the recommendations is therefore weak. In the angular deviation treatment, statistically significant differences were observed in the accuracy of the implants with tooth vs bone support: Bone support yielded 1.31 degrees greater deviation vs tooth support (SD = 0.43; 95% CI: 0.47, 2.15, P = .002). No significant differences were observed in the linear deviations. Conclusion: Tooth support proved to be significantly more precise than bone support splints. There were no differences referring to horizontal coronal deviation, horizontal apical deviation, or vertical deviation according to the type of splint support used.

Purpose: To study whether the use of preventive antibiotic therapy reduces the sinus graft infection and/or dental implant failure rates in maxillary sinus elevation surgeries (primary outcome), and to identify the associated best protocol (secondary outcome). Materials and Methods: The MEDLINE (via PubMed), Web of Science, Scopus, LILACS, and OpenGrey databases were searched between December 2006 and December 2021. Prospective and retrospective comparative clinical studies with at least 50 patients and published in English were included. Animal studies, systematic reviews and meta-analyses, narrative literature reviews, books, case reports, letters to the editor, and commentaries were excluded. Assessment of the identified studies, data extraction, and risk of bias were performed independently by two reviewers. Authors were contacted if required. Collected data were reported by descriptive methods. Results: A total of 12 studies fulfilled the inclusion criteria. The only retrospective study comparing the use of antibiotics vs no use of them showed no statistically significant differences for implant failure; however, no data were reported for sinus infection rates. The only randomized clinical trial comparing different courses of antibiotics (only the day of surgery vs 7 additional postoperative days) reported no statistically significant differences between groups in terms of sinus infection rate. Conclusion: Not enough evidence is available to support either the use or nonuse of preventive antibiotic therapy for sinus elevation surgeries or to support the superiority of any protocol over others.

Purpose: To investigate and assess the differences in crestal bone loss (CBL) between wide-diameter, external-hexagon-connection implants restored with platform-switching (PS) and platform-matching (PM) restorations with a follow-up of 10 years. Materials and Methods: This study retrospectively analyzed the updated and enlarged dataset of a 5-year prospective clinical study at 10-year follow-up. The data concerns 182 healthy adult subjects treated in a private dental practice who received a single wide-diameter implant with an external hexagon connection in the molar area, restored with either a PS restoration (test) or PM restoration (control). The amount of CBL was radiographically measured at each annual follow-up, as well as after 5 and 10 years of implant loading. In evaluating the association between the two types of abutments and bone loss (including change over time), a linear mixed effects model was run for longitudinal data. Results: Implants connected with PS restorations exhibited significantly lower reduction (0.25 mm) in CBL than those joined to PM restorations (P < .001; 95% CI from 0.22 to 0.29). However, both groups presented a higher increase in bone loss during the first year (0.58 mm in PS and 0.83 mm in PM) and a linear increment thereafter until the 10-year follow-up (0.046 mm/year; P < .001; 95% CI from .042 to .049). Conclusion: Notwithstanding the limitations of this study, it can be concluded that after 10 years of follow-up, the implant with a wide diameter and external-hexagon connection restored with a PS abutment seems to be more effective in reducing bone loss compared with the PM abutment.

Purpose: To evaluate the effect of insertion depth, bone type, and implant diameter on the primary stability of short implants. Materials and Methods: Commercial dental implants with different lengths (6 and 8 mm; BLX, Straumann) were inserted into artificial bone specimens of good and poor quality at three different depth positions: equicrestal, 1-mm subcrestal, and 2-mm subcrestal. Insertion torque values were recorded spontaneously during the implant procedure. Both maximum insertion torque values (MITVs) and final insertion torque values (FITVs) were recorded. Subsequently, Periotest values (PTVs) and implant stability quotients (ISQs) were measured for all specimens. Results: The mean MITVs of all groups ranged from 31.8 to 46.2 Ncm. However, the mean FITVs of all groups ranged from 8.8 to 29 Ncm. Torque values decreased significantly when the implants were inserted into their final positions. When insertion depth was increased, the PTV and ISQ decreased. Long implants and implants inserted into good-quality bone yielded greater primary stability, and bone quality appeared to have a greater effect on primary stability. Conclusion: When 6-mm short implants are inserted in a subcrestal position, low primary stability may be yielded, particularly in poor-quality bone.