Comparative evaluation of BioHPP and titanium as a framework veneered with composite resin for implant-supported fixed dental prostheses.

STATEMENT OF PROBLEM: High rates of veneering chipping are a common prosthodontic complication of restorations with a titanium framework. A new bio high-performance polymer (BioHPP) based on polyetheretherketone (PEEK) has been introduced for denture superstructures. Clinical reports suggest that BioHPP could be used as an alternative framework material to support complete-arch restorations. However, peer-reviewed information is lacking regarding the performance of BioHPP as a framework material for implant-supported screw-retained fixed dental prostheses (FDPs) veneered with composite resin. PURPOSE: The purpose of this in vitro study was to evaluate and compare the bond strength of modified PEEK (BioHHP) and titanium with a veneering composite resin and compare the marginal fit and fracture resistance of implant-supported screw-retained FDPs fabricated by using computer-aided design and computer-aided manufacturing (CAD-CAM) frameworks veneered with composite resin. MATERIAL AND METHODS: A composite resin was bonded to 2 framework materials (n=20/group): pure titanium (Ti) and BioHPP (Bi). The shear bond strength (SBS) was determined after 24-hour wet storage. Furthermore, 20 3-unit CAD-CAM BioHPP and titanium frameworks were fabricated (n=10/group). The marginal fit between frameworks and abutments was evaluated by scanning electron microscopy by using the single-screw test. After thermocycling and mastication simulation, the fracture resistance of FDPs veneered with the composite resin was examined. The independent sample t test was used to evaluate differences (α=.05). RESULTS: Significantly higher shear bond strengths were obtained in group Bi (31.1 ±3.5 MPa) than in group Ti (20.5 ±1.8 MPa). The mean marginal gap width was 19 ±4 µm in group Bi and 16 ±6 µm in group Ti. Statistical tests showed no significant differences (P>.05). After loading, veneering chipping was observed at a load of 1960 ±233 N in group Ti. Although the BioHPP frameworks fractured at 1518 ±134 N, no chipping occurred. CONCLUSIONS: The bond strength of BioHPP with the composite resin was greater than that of titanium. CAD-CAM BioHPP frameworks exhibit good marginal fit and fracture resistance. BioHPP may be a suitable alternative to metal as a framework to be veneered with composite resin.

Effect of CAD/CAM Guide Plate Combined With Socket-Shield Technique in Immediate Implantation of Anterior Teeth Aesthetic Area and Its Influence on Aesthetics.

PURPOSE: The purpose of this study is to discuss the effect of computer-aided design or computer-aided manufacturing (CAD/CAM) guide plate combined with socket-shield technique (SST) in immediate implantation of anterior teeth aesthetic area and its influence on aesthetics. METHODS: A total of 102 patients with immediate implantation in our hospital from March 2017 to March 2020 were selected. According to different repair methods, patients were divided into conventional group (n = 51) and observation group (n = 51). Traditional immediate implantation was performed in conventional group. The observation group underwent immediate implantation with CAD/CAM guides combined with SST. Immediately after operation and 12 months after operation, the success rate, implant deviation, periodontal index, absorption of labial bone plate, complications, aesthetic effects, and satisfaction of the two groups were observed. RESULTS: There was no significant difference in the success rate between the two groups (p > 0.05). The implant deviation values in the observation group were all lower than those in the conventional group (p < 0.05). PD, PLI, and SBI in the observation group were all lower than those in the conventional group (p < 0.05). The absorption value of labial bone plate in the observation group were all lower than those in the conventional group (p < 0.05). The total incidence of complications in the observation group (5.88%) was lower than that in the conventional group (19.61%) (p < 0.05). The PES and WES in the observation group were higher than those in the conventional group (p < 0.05). The total satisfaction in the observation group (92.16%) was higher than that in the conventional group (76.47%) (p < 0.05). CONCLUSION: : The application of CAD/CAM guide plate combined with SST in immediate implantation of anterior teeth aesthetic area has a good effect, which can improve the accuracy of implantation, improve the periodontal environment, reduce bone resorption, reduce complications, improve aesthetics, and have high patient's satisfaction.

Modified Disk-Up Sinus Reamer for Sinus Floor Elevation and Simultaneous Implant Placement: An Animal Study with Miniature Pigs.

Objective: The disk-up sinus reamer (DSR) is a modified instrument used to elevate the maxillary sinus floor. This study aimed to compare the effects of modified DSR sinus floor elevation (DSFE) with osteotome sinus floor elevation (OSFE), both with simultaneous implant placement. Methods: Twelve miniature pigs were treated with DSFE on one side and OSFE on the other. Implants 9 mm in length were placed in six pigs without grafting, while implants 11 mm in length were placed in the other six pigs with grafting. After submerged healing for 3 months, vertical bone gain (VBG), general and histological observation, and bone contact ratio (BCR) were analyzed. Results: The mean maxillary residual bone height (RBH) when implants were placed was 6.45 ± 0.36 mm. In the no-grafting group, DSFE and OSFE had a similar VBG after 3 months. The grafting group with DSFE recorded a significantly higher VBG (VBG0: 7.83 ± 0.44 mm, VBG1: 7.54 ± 0.40 mm) than the graft group with OSFE (VBG0: 5.45 ± 0.56 mm, VBG1: 4.34 ± 2.15 mm) (p < 0.05). One implant became loose and the sinus mucosa of three pigs appeared metallic in color on the control side (OSFE). Conclusions: The effect of OSFE and DSFE is similar when there is no need for grafting. DSFE seems a better alternative method for sinus floor elevation with grafting when more VBG is needed.

Masticatory efficiency and oral health-related quality of life with implant-retained mandibular overdentures.

OBJECTIVES: To evaluate masticatory efficiency (ME) and oral health-related quality of life (OHRQoL) in patients rehabilitated with implant-retained mandibular overdentures. METHODS: In this randomized controlled clinical trial, 50 edentulous patients visiting the Implant Center and Department of Prosthodontics, West China College of Stomatology, Sichuan University, Chengdu, China between June 2010 and June 2012 were selected and received 2 implant-retained mandibular overdenture treatments. All patients were rehabilitated with maxillary complete dentures. The ME and OHRQoL were determined both one month before the mandibular complete denture was anchored to the osseointegrated implants, and 6 months after anchoring. Paired t-tests were used to compare means of ME, and oral health impact profile-49 (OHIP-49)  domains scores between pre- and post-implant. Linear regression models were utilized to seek correlations between ME and OHIP domains scores. RESULTS: The ME increased from pre- to post-implant retained mandibular overdentures significantly (p<0.001). The total OHIP score and 4 subscales scores were changed significantly from pre- to post-implant; namely, functional limitation, psychological discomfort, physical disability, and physical pain. The total OHIP score, functional limitation, physical disability, and physical pain subscale scores were related to ME. CONCLUSION: Implant-retained mandibular over dentures can significantly improve patients' ME and OHRQoL. The improvement in OHRQoL is mainly because of the improved ME. An improved chewing experience, and pain relief also contributes to improvement of OHRQoL. 

Osteoblast response to titanium surfaces coated with strontium ranelate-loaded chitosan film.

PURPOSE: Improving the peri-implant bone quality has notable clinical value in cases of osteoporosis following implant insertion. MATERIALS AND METHODS: In this study, strontium ranelate-loaded chitosan film was produced on a titanium surface in different concentrations of strontium ranelate (SR) (0, 2, 20, 40, and 80 mmol/L of the strontium ion [Sr2+]) with the expectation of utilizing the bone healing-enhancement effect of Sr2+. The physicochemical properties of SR-loaded chitosan films were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The release/dissolution mechanism was tested by inductively coupled plasma optical emission spectrometry (ICP-OES), and in vitro cell responses were evaluated using primary osteoblasts (POBs) in terms of cell proliferation, alkaline phosphatase (ALP) activity, and quantitative analysis of key osteoblastic gene expression. RESULTS: XRD and FTIR observation showed that only a few SRs reacted chemically with chitosan through hydrogen bonds or conjugate action. The initial burst release (70% to 85%) of Sr2+ occurred in the first 3 days and was followed by a slower release stage. At a low concentration (2 mmol/L or 20 mmol/L), SR-loaded chitosan film promoted cell responses of POBs with enhanced proliferation, ALP activity, and expression levels of bone morphogenetic protein 2 (BMP-2), runt-related transcription factor 2 (Runx-2), ALP, and osteocalcin, but at a high concentration (40 mmol/L or 80 mmol/L), it inhibited POB growth. CONCLUSION: These results indicated that SR-loaded chitosan film on a titanium surface promotes osteoblast proliferation and differentiation in a dose-dependent manner, which may represent a new approach in the treatment of a titanium implant.

[The effect of maxillary and mandibular lip bumper on teeth and dental arch in late mixed dentition].

PURPOSE: To study the effect of maxillary and mandibular lip bumper on tooth and dental arch in late mixed dentition. METHODS: Twelve subjects with mild or moderate crowding were selected. They were treated with maxillary and mandibular lip bumper for eight months. Analysis of cephalometrics and model measurements were done before and after treatment and paired t test were performed respectively for their changes. RESULTS: After treatment, SNA and SNB increased by 1.02 degrees and 0.97 degrees (P<0.05). Upper and lower incisor both had controlled tipping movement. The crown of incisor moved mesially and had root apex were fixed relatively. The center of rotation was close to root apex. The upper and lower molar moved differently. Upper molar was upright distally and the center of rotation was close to the crown. However, the lower molar tipped distally and the center of rotation was close to the center of resistance.The width between the first molars and length of maxillary dental arch increased by 4.12 mm and 5.09 mm (P<0.01). The width between the first molars and length of mandibular dental arch increased by 4.07 mm and 6.86 mm (P<0.01) CONCLUSION: Clinical application of lip bumper could cause transverse and vertical changes in dental arch ,which help to decrease or remove crowding.