Mini-implant mandibular overdentures under a two-step immediate loading protocol: A 4-6-year retrospective study.

OBJECTIVES: This retrospective study to evaluate the treatment outcomes of mandibular mini-implant overdentures (MIODs) placed under a two-step immediate loading protocol. BACKGROUND: The mini-implant overdenture emphasises the advantages of simplicity using flapless surgery and immediate loading. However, some mini-implant have lowe initial stability. MATERIALS AND METHODS: A total of 30 participants who used mandibular MIODs and maxillary removable complete dentures (RCDs) over 4 years were included. Four one-piece mini-implants (<3 mm in diameter) were placed by a flapless surgical approach after fabrication of new RCDs, and the O-ring attachment was attached at least 8 weeks after implant placement. RESULTS: The average observation period was 58.9 ± 9.2 months after mini-implant loading. The survival rate of the implants was 100.0%, and the overall change in mean marginal bone level (ΔMBL) was -0.9 ± 1.1 mm. The implant success rate was 83.3% at the implant level, and 66.7% at the patient level. The mean initial Periotest value was 0.9 ± 3.1, and it was positively associated with ΔMBL and implant success (P < .05). Patient satisfaction improved after conversion from RCDs to MIODs (P < .05), and mastication and pain showed greater satisfaction with longer loading time (P < .05). CONCLUSIONS: The mandibular MIODs could be chosen as an alternative treatment under a two-step immediate-loading protocol in edentulous patients with limited alveolar bone volume. To ensure superior treatment outcomes of MIODs, initial stability of implant must be obtained using as wide a diameter as possible within the anatomically allowable limits.

Narrow-diameter versus regular-diameter dental implants for mandibular overdentures: A systematic review and meta-analysis.

PURPOSE: The aim of this systematic review was to compare treatment outcomes in terms of implant survival rate, marginal bone loss, and patient-reported outcome measures (PROMs) between narrow-diameter implants and regular-diameter implants (RDIs) for mandibular implant overdentures (MIOs). METHODS: This study was based on the methodology adapted as per Cochrane. Medline, Embase, the Cochrane Central Register of Controlled Trials, Web of Science, and Scopus were searched for pertinent studies published by July 22, 2022. Outcome parameters included in this meta-analysis were implant survival rate, marginal bone loss, visual analogue scale score for patient satisfaction, and value of oral health impact profile. RESULTS: A total of 782 non-duplicate articles and 83 clinical study registrations were identified from database and hand searches, of which 26 were eligible for full-text searches. Finally, 12 publications reporting on 8 independent studies were included in this review. In the meta-analysis, implant survival rate and marginal bone loss did not significantly differ between narrow-diameter implants and RDIs. Regarding RDIs, narrow-diameter implants were associated with significantly better outcomes in general patient satisfaction and oral health-related quality of life than RDIs for mandibular overdentures. CONCLUSIONS: Narrow-diameter implants have competitive treatment outcomes compared to RDIs in terms of implant survival rate, marginal bone loss, and PROMs. [Correction added on July 21, 2023, after first online publication: The abbreviation RDIs was changed to PROMs in the preceding sentence.] Thus, narrow-diameter implants might be an alternative treatment option for MIOs in situations with limited alveolar bone volume.

Accuracy of implant impression techniques with a scannable healing abutment.

STATEMENT OF PROBLEM: Scannable healing abutments are a convenient option to facilitate impression making for implant-supported restorations. However, studies evaluating the accuracy of the impression technique with scannable healing abutments are lacking. PURPOSE: The purpose of this in vitro study was to evaluate the accuracy of implant impression techniques with scannable healing abutments. MATERIALS AND METHODS: A partially edentulous mandibular dentiform model was fabricated with an epoxy resin, and implants were placed in the mandibular right second premolar and first molar areas. A maxillary dentiform model was then fabricated, and both models were mounted on an articulator. Scan data were obtained from the mounted models and set as the reference scans. The experimental models were divided into 4 groups (n=10). The conventional pick-up impression technique and definitive casts were used in group CI. The scan data from the definitive casts were obtained with a 3D model scanner. An intraoral scanner with a digital body scan was used in group DS. Group MS yielded definitive casts with dual-arch impressions with scannable healing abutments. The fabricated definitive casts were mounted and scanned with a 3D cast scanner. Intraoral scanning with scannable healing abutments was used in group IS. In all 4 groups, the interarch relationship in the maximum intercuspal position was obtained by scanning the facial aspect. The center of the implant head was set as a measurement point for linear intra-arch deviations and implant angle deviations. The mesiopalatal cusp tip of the maxillary right first molar was used to calibrate the linear interarch deviations. The data obtained from each group were compared with the data from the reference scan. As the data were not normally distributed, the Kruskal-Wallis test and Bonferroni correction were used for the analysis (α=.05). RESULTS: Group MS exhibited significantly higher deviations in linear intra-arch and implant angles compared with the other groups (P<.05). No significant difference was found between the groups in linear interarch deviations (P>.05). CONCLUSIONS: The accuracy of intraoral scanning with scannable healing abutments was comparable with that of conventional pick-up impression techniques and digital scans with scan bodies. However, model scanning with scannable healing abutments may not be clinically acceptable for implant impressions.

Effect of conversion to implant-assisted removable partial denture in patients with mandibular Kennedy classification â : A systematic review and meta-analysis.

OBJECTIVE: This review evaluated the change in treatment outcomes after conversion from conventional removable partial denture (RPD) to implant-assisted removable partial denture (IARPD). The patient-reported outcome measures (PROMs), objective parameters for evaluation of functional performance, and biological and mechanical complication were evaluated. MATERIALS AND METHODS: This systematic review was based on the Cochrane review methodology and followed the criteria of the preferred reporting items for systematic reviews and meta-analyses (PRISMA). We searched MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, Web of Science, and Scopus up to April 3, 2019. After the initial search, additional electronic and hand searches were performed to identify further studies, ongoing studies, and gray literature, without restrictions on language, year of publication, or publication type. RESULTS: In total, 6,544 non-duplicate articles were identified, and 31 were eligible for full-text search. Finally, 19 publications based on 13 independent studies were selected. In the meta-analysis, general patient satisfaction was significantly increased (p < .05), and the improved mastication was remarkable oral function. In oral health-related quality of life, the oral health impact profile score was significantly improved, and improvements of physical pain and psychological disability were prominent (p < .05). Masticatory performance was improved in terms of maximum bite force, active occlusal contact area, and mandibular jaw movement (p < .05). The weighted mean survival rate of implants was 96.60%. CONCLUSIONS: After conversion from conventional RPD to IARPD, the PROMs and masticatory performance significantly improved in partially edentulous patients under mandibular Kennedy classification I.

Bar versus ball attachments for maxillary four-implant retained overdentures: A randomized controlled trial.

OBJECTIVES: To compare the clinical treatment outcomes of maxillary four-implant retained overdentures with either splinted (bar) attachments or non-splinted (ball) attachments. MATERIAL AND METHODS: Forty participants who were dissatisfied with their existing conventional maxillary complete dentures were included in this randomized controlled trial. Six months after implant placement, a definitive prosthesis was inserted. Implant success, condition of peri-implant tissue, prosthodontic maintenance and complications, and patient satisfaction were assessed. Outcomes were recorded at baseline, prosthesis delivery, and at 3 and 12 months following prosthesis delivery, and a statistical analysis was performed. RESULTS: Thirty-two of the forty patients completed the 1-year follow-up and had their treatment outcomes evaluated. The mean marginal bone loss after 1 year of loading was 0.34 ± 0.88 mm, and there were no significant differences between the two groups. Plaque index, gingival index and bleeding on probing were significantly higher in the bar group (p<.001), and the implant success rate of the bar group was significantly lower than that of the ball group (p=.028). The most frequent prosthodontic maintenance and complication issue was the need to change the bar clip or O-ring as a result of retention loss. Patient satisfaction did not differ between the two groups except for aesthetics at 3 months. CONCLUSIONS: Within the limitations of this study, the maxillary 4-implant retained overdenture exhibited predictable results regardless of the attachment systems (ball or bar) in the 1-year follow-up period. The bar group was more vulnerable than the ball group with respect to maintaining peri-implant tissue health.

Serum immunoglobulin fused interferon-alpha inhibited tumor growth in athymic mice bearing colon 26 adenocarcinoma cells.

Interferon (IFN) has therapeutic potential for a wide range of infectious and proliferative disorders. However, the half-life of IFN is too short to have a stable therapeutic effect. To overcome this problem, serum immunoglobulin has been fused to IFN. In this study, the efficacy of serum immunoglobulin fused INFs (si-IFN1 and si-IFN2) was evaluated on athymic mice bearing colon 26 adenocarcinoma cells. Seven days after the implantation of tumor cells, each group of mice was injected once a week with si-IFN1 and si-IFN2 at two different concentrations (10 x : 30 microg/kg and 50 x : 150 microg/kg). A slight anti-tumoral effect was observed in all 10 x groups compared to the control. In the 50 x groups, however, si-IFN1 and si-IFN2 showed significant anti- tumoral effects compared to the control. To gain more information on the mechanisms associated with the decrease of tumor size, a Western blot assay of apoptosis-related molecules was performed. The protein expression of cytochrome c, caspase 9, 6, and 3 were increased by si-IFN1 and si-IFN2. These 2 IFNs also increased the expressions of p53, p21, Bax and Bad. Interestingly, si-IFN1 and si-IFN2 decreased the expression of VEGF-beta. Taken together, serum immunoglobulin fused IFNs increased therapeutic efficacy under current experimental condition.

Two-Step Immediate Loading of Mandibular Overdentures Retained by Mini-implants: A Prospective Clinical Study.

PURPOSE: This study aimed to evaluate treatment outcomes of mandibular overdentures retained by two different mini-implant systems with ball attachments under a two-step immediate loading protocol. MATERIALS AND METHODS: This clinical trial investigated treatment outcomes of mandibular mini-implant overdentures in 45 edentulous patients. MDI implants (3M ESPE) and SlimLine implants (Dentium) were randomly selected for placement in the anterior mandible in each group (MDI = 21; SlimLine = 24) with a flapless surgical approach. The side of the tissue in the region of the complete mandibular denture where mini-implants were placed was immediately relined with soft reliner (COE-SOFT). The female components were attached on the dentures 2 months after implant placement. Clinical and radiographic data were collected during follow-up. Statistical analyses were performed using SPSS software version 22.0 (α = .05). RESULTS: A total of 177 mini-implants were inserted in the anterior mandibles of 45 totally edentulous patients. There were five implant failures (97.2% success rate) and no significant differences between the two implant groups. Most mini-implants showed stable initial Periotest values (a mean ± standard deviation of 1.03 ± 3.65 mm) and a mean marginal bone loss of 0.50 ± 0.75 mm at 12 months. Multiple regression analysis revealed that implants ≤ 2.4 mm in diameter had higher Periotest values than those ≥ 2.8 mm. Intial Periotest values significantly influenced implant failure (P < .05). CONCLUSION: There were no significant differences in treatment outcomes between patients treated with MDI or SlimLine implants. Mini-implants with wider diameters showed higher initial stability than those with narrow diameters, which may influence implant survival.

Effects of relining materials on the flexural strength of relined thermoplastic denture base resins.

PURPOSE: The aim of this study was to evaluate the effects of relining materials on the flexural strength of relined thermoplastic denture base resins (TDBRs). MATERIALS AND METHODS: For shear bond strength testing, 120 specimens were fabricated using four TDBRs (EstheShot-Bright, Acrytone, Valplast, Weldenz) that were bonded with three autopolymerizing denture relining resins (ADRRs: Vertex Self-Curing, Tokuyama Rebase, Ufi Gel Hard) with a bond area of 6.0 mm in diameter and were assigned to each group (n=10). For flexural strength testing, 120 specimens measuring 64.0×10.0×3.3 mm (ISO-1567:1999) were fabricated using four TDBRs and three ADRRs and were assigned to each group (n=10). The thickness of the specimens measured 2.0 mm of TDBR and 1.3 mm of ADRR. Forty specimens using four TDBRs and 30 specimens using ADRRs served as the control. All specimens were tested on a universal testing machine. For statistical analysis, Analysis of variance (ANOVA) with Tukey's test as post hoc and Spearman's correlation coefficient analysis (P=.05) were performed. RESULTS: Acry-Tone showed the highest shear bond strength, while Weldenz demonstrated the lowest bond strength between TDBR and ADRRs compared to other groups. EstheShot-Bright exhibited the highest flexural strength, while Weldenz showed the lowest flexural strength. Relined EstheShot-Bright demonstrated the highest flexural strength and relined Weldenz exhibited the lowest flexural strength (P<.05). Flexural strength of TDBRs (P=.001) and shear bond strength (P=.013) exhibited a positive correlation with the flexural strength of relined TDBRs. CONCLUSION: The flexural strength of relined TDBRs was affected by the flexural strength of the original denture base resins and bond strength between denture base resins and relining materials.

Treatment Outcomes for Mandibular Mini-Implant-Retained Overdentures: A Systematic Review.

PURPOSE: This systematic review evaluated treatment outcomes for mandibular mini-implant-retained overdentures (MMIOs) in terms of (1) implant survival rate, (2) peri-implant marginal bone loss, (3) prosthodontic maintenance and complication occurrence, and (4) patient satisfaction. MATERIALS AND METHODS: Pertinent literature published in English before October 12, 2015 was identified using a MEDLINE and EMBASE search strategy and hand searching of relevant journals. Inclusion and exclusion criteria were applied to the titles and abstracts and subsequently to the full text of included studies. A total of 16 articles were included, from which qualitative and quantitative data were extracted for analysis. RESULTS: Of the 16 evaluated articles, 5 were randomized controlled trials, 8 were prospective studies, and 3 were retrospective studies. The follow-up time range from implant placement was 1 to 6 years, and only four studies included more than 3 years of follow-up. The mini-implant survival rate ranged from 86.9% to 100%. Mean marginal bone resorption was 0.28 to 1.2 mm after 1 year of loading. Of the 16 studies, 5 reported prosthodontic maintenance and complications, and all included studies showed significant improvement in patient satisfaction. CONCLUSION: Despite the limitations of this systematic review, particularly the short follow-up periods, the results suggest that MMIOs showed predictable results regarding implant survival rates, marginal bone resorption, and patient satisfaction.

Fabricating a Maxillary Obturator Using an Intraoral Digital Impression: A Case History Report.

Digital impressions can be a useful option that reduces patient discomfort and simplifies clinical procedures such as accurate impression recordings. In this report, a patient with a partial maxillectomy was managed with a metal frame fabricated from a digital impression through an intraoral scanner. The final impression employed the altered cast technique for the fabrication of the obturator.

Poly-4-vinylphenol and poly(melamine-co-formaldehyde)-based graphene passivation method for flexible, wearable and transparent electronics.

Next generation graphene-based electronics essentially need a dielectric layer with several requirements such as high flexibility, high transparency, and low process temperature. Here, we propose and investigate a flexible and transparent poly-4-vinylphenol and poly(melamine-co-formaldehyde) (PVP/PMF) insulating layer to achieve intrinsic graphene and an excellent gate dielectric layer at sub 200 °C. Chemical and electrical effects of PVP/PMF layer on graphene as well as its dielectric property are systematically investigated through various measurements by adjusting the ratio of PVP to PMF and annealing temperature. The optimized PVP/PMF insulating layer not only removes the native -OH functional groups which work as electron-withdrawing agents on graphene (Dirac point close to zero) but also shows an excellent dielectric property (low hysteresis voltage). Finally, a flexible, wearable, and transparent (95.8%) graphene transistor with Dirac point close to zero is demonstrated on polyethylene terephthalate (PET) substrate by exploiting PVP/PMF layer which can be scaled down to 20 nm.

Can concurrent chemoradiotherapy replace surgery and postoperative radiation for locally advanced stage III/IV tonsillar squamous cell carcinoma?

AIM: To compare surgery and postoperative radiotherapy (PORT) with the non-surgical combination of chemotherapy and radiation therapy (CCRT) for locally advanced squamous cell carcinoma (SCC) of the tonsil by measuring treatment outcomes and treatment-related complications. PATIENTS AND METHODS: The records of 114 patients with non-metastatic stage III/IV tonsillar SCC treated between July, 1998 and December, 2010 were reviewed retrospectively. Among the 114 patients, 65 received PORT and 49 received CCRT. In the PORT group, treatment included wide surgical resection of the tumor with neck dissection and administration of PORT to the primary tumor bed with a median dose of 60 Gy. In the CCRT group, a median dose of 70 Gy was delivered to the gross tumor, and 46 patients received concurrent chemotherapy with i.v. cisplatin. The median follow-up time was 58 months in the PORT group and 44 months in the CCRT group. RESULTS: There was no significant difference between PORT and CCRT in terms of 5-year locoregional recurrence-free survival (88.4% vs. 91.4%, p=0.68), distant metastasis-free survival (88.9% vs. 92.3%, p=0.60), disease-free survival (79.5% vs. 84.2%, p=0.63) or overall survival (78.9% vs. 88.9%, p=0.45). More CCRT patients than PORT patients experienced grade 3 (or higher) hematological toxicities and grade 2 pharyngitis during treatment. Chronic toxicity, manifested as swallowing difficulty, dry mouth and trismus, was similar between the two treatment groups. CONCLUSION: CCRT provides similar levels of local and distant control in patients with locally advanced tonsillar SCC as PORT, yet fails to show any superiority in preserving functions such as swallowing, saliva production, and mastication.