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.

[Review of clinical effects of disk-up sinus reamer(DSR)-based internal sinus floor elevation with implantation in 10 years].

PURPOSE: To analyze the bone remodeling around the implant 10 years after disk-up sinus reamer(DSR)-based internal sinus floor elevation with implantation and to investigate the influence of different factors on implant retention. METHODS: The clinical and imaging data of patients undergoing DSR-based sinus floor elevation with simultaneous implantation were collected from the Department of Dental Implantology, Affiliated Hospital of Qingdao University from January 2008 to December 2011. Panoramic film and CBCT were used to measure the changes of bone mass around implant in different periods. Kaplan-Meier and Log-rank tests were used to analyze the effects of different factors on implant retention with SPSS 26.0 software package. RESULTS: The study included 98 patients with a total of 128 implants. During the follow-up of 0-168 months, 7 implants failed, and the remaining formed good osseointegration and functioned, with a 10-year cumulative retention rate of 94.53%. The height of bone formation was (0.29±0.15) mm at the top and (2.74±0.66) mm in the sinus of 75 implant sites with complete imaging data obtained ten years after surgery. Kaplan-Meier and Log-rank tests showed that 8 factors including initial bone height, elevated bone height, mucosal perforation, implant length, implant torsion, diabetes, smoking and periodontitis had significant effects on implant retention. CONCLUSIONS: The DSR-based internal sinus floor elevation with implantation is a reliable and stable bone augmentation operation for vertical bone defect in maxillary posterior region, with a 10-year cumulative retention rate of no less than 94%. Initial bone height, elevated bone height, mucosal perforation, implant length, implant torsion, diabetes, smoking and periodontitis are the important factors affecting the long-term retention rate of implants.

[Effect of PRRX1 on autophagy of salivary adenoid cystic carcinoma cells].

PURPOSE: To investigate the effect of paired related homeobox1 (PRRX1) on autophagy of salivary adenoidcystic carcinoma (SACC) cells. METHODS: PRRX1-overexpressed lentiviral vectors and their negative control lentiviral vectors were used to transfect SACC cells. The transfection effect was detected by Western blot. Autophagosome was observed under transmission electron microscopy(TEM). The level of autophagy markers (LC3-II/Beclin1) was detected by immunofluorescence and Western blot. Statistical analysis was performed with SPSS 17.0 software package. RESULTS: PRRX1 protein level increased, autophagosome number decreased, and autophagy marker level decreased in the PRRX1 overexpressed group, compared to the control (P<0.05). CONCLUSIONS: PRRX1 inhibits the autophagy of SACC cells.

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.

In Vitro Corrosion and Cytocompatibility of a Microarc Oxidation Coating and Poly(L-lactic acid) Composite Coating on Mg-1Li-1Ca Alloy for Orthopedic Implants.

Manipulating the degradation rate of biomedical magnesium alloys poses a challenge. The characteristics of a microarc oxidation (MAO), prepared in phytic acid, and poly(L-lactic acid) (PLLA) composite coating, fabricated on a novel Mg-1Li-1Ca alloy, were studied through field emission scanning electron microscopy (FE-SEM), electron probe X-ray microanalysis (EPMA), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). The corrosion behaviors of the samples were evaluated via hydrogen evolution, potentiodynamic polarization and electrochemical impedance spectroscopy in Hanks' solution. The results indicated that the MAO/PLLA composite coatings significantly enhanced the corrosion resistance of the Mg-1Li-1Ca alloy. MTT and ALP assays using MC3T3 osteoblasts indicated that the MAO/PLLA coatings greatly improved the cytocompatibility, and the morphology of the cells cultured on different samples exhibited good adhesion. Hemolysis tests showed that the composite coatings endowed the Mg-1Li-1Ca alloys with a low hemolysis ratio. The increased solution pH resulting from the corrosion of magnesium could be tailored by the degradation of PLLA. The degradation mechanism of the composite coatings was discussed. The MAO/PLLA composite coating may be appropriate for applications on degradable Mg-based orthopedic implants.

UV spectroscopic studies and charge transfer properties of azobenzene-containing cyclopentadienyliron complexes of arenes: a combined experimental and density functional theoretical study.

This study investigates the UV-Vis absorption and fluorescence emission of newly synthesized (η(6)-4-(4-nitrophenylazo) phenoxyl benzene) (η(5)-cyclopentadienyl) iron hexafluorophosphate (Fc-azo). Quantum chemical calculations of the orbital energy, geometrical structure, absorption spectra, and first hyperpolarizability (ß) values of the Fc-azo were carried out using density functional (DFT/B3LYP and TD-DFT) methods. Comparisons between hydroxyl azobenzene compound and Fc-azo were made. Results showed that the observed spectra were in good agreement with the calculated values. The positive solvatochromism of the UV-Vis absorption of Fc-azo upon the increase in solvent polarity from the experiment and the calculated HOMO and LUMO energies showed that charge transfer occurred within the molecule. Moreover, the change in electron distribution led to the improved ß for Fc-azo.

[Influence of platform switching on crest bone maintenance around implants: a radiographic investigation in dogs].

PURPOSE: To evaluate and compare the dynamic changes in functional loading or non-functional loading with platform-switching (PLS) implants and butt-joint implants,and to refine the factors leading to marginal bone loss around PLS. METHODS: Six adult dogs were selected and numbered randomly.The second,third and fourth premolars in bilateral mandible of each dog were extracted. After 3 months, the implantation operation was carried out. There were 3 kinds of implants, 36 implants in total, which were divided in to 3 groups: Group A,Group G and Group U. In particular order, A, G and U were placed on each side of every dog. Three months later, the 2nd surgery was begun. At the 4th month from the 1st surgery, for each dog, on the right side only, the abutments were installed and impression was taken. Then, after 2 weeks, the dental prostheses were put on. All dogs were executed at the end of the 12th month. X-ray film was taken at the 3rd, 6th, 9th and 12th month and the moment of the 1st surgery (baseline). Measurements were made between the implant shoulder (IS),the most coronal level of bone in contact with implant (CLB), and the level of alveolar bone crest (BC). According to the different groups of implants (A, G, U), all records were analyzed with paired and Wilcoxon's signed rank test using SPSS11.5 software package. RESULTS: The mean IS-CLB and IS-BC values of group A, G were significantly different with those of group U at the 6th, 9th and 12th month, while there was no significant difference between group A and G. No matter they were loading or not, the self-comparison of each kind of implant presented no significant difference. There was no significant difference between every kind of implant on their self-comparison during the first three months; while, the differences were significant during the next 9 months. CONCLUSIONS: The most significant changes in the absorption of marginal bone around two stage submerged implant can be observed after 3 months of implanting. The bone absorption was not related to functional loading or not.

[Parotid major duct cyst: a case report].

Parotid gland cyst can be congenital or acquired, which is rarely seen in clinic. Cysts in the main duct of the parotid gland are especially rare. We reported a 37-year-old man who presented with a painless mass on the right cheek. Superficial parotidectomy was performed and histopathologic examination of the specimen revealed a main parotid duct cyst. The clinical features, diagnosis, and treatment of the case were discussed and the relevant literatures were reviewed.

[Clinical study of transcrestal maxillary sinus floor elevation with the disk-up sinus reamer].

OBJECTIVE: To evaluate the clinical effect of the disk-up sinus reamer (DSR) applied to transcrestal maxillary sinus floor elevation with simultaneous placement of implants. METHODS: Thirty-seven patients underwent transcrestal maxillary sinus floor elevation with fifty-one implants placed simultaneously using the DSR. The residual bone height (RBH) was 3 to 8 mm, (5.61 ± 1.61) mm on average. The safety of this technique and the pain index during the operation was evaluated. The final prostheses were restored in 3-6 months postoperatively. The follow-up period was 3 to 24 months. The stability and osseointegration of the implants were clinically evaluated, and the endo-sinus bone gain around the implants were measured. RESULTS: The elevation height ranged from 2 to 8 mm, with an average of (4.75 ± 1.55) mm. There was no detectable sinus membrane perforation, no serious suffering or uncomfortable subjective sensation in any patients during operation with a pain index of (2.22 ± 0.98). During the follow-up period, no sinus complication was observed. Favorable osseointegration was obtained. There were no implants or prostheses which were loose or lost. The survival rate was 100%. The radiographic results demonstrated that the endo-sinus bone gain tended to reach stabilization after 6 months and the marginal bone loss was (1.20 ± 0.72) mm after 12 months. CONCLUSIONS: Transcrestal maxillary sinus floor elevation with simultaneous implant placement by DSR is a safe, invasive and handy technique, with higher elevation height, fewer clinical complications and less pain. It shows satisfactory clinical results in short term and a long-term observation is still needed.

[Clinical efficacy of immediate implants restoration in anterior zone].

PURPOSE: To elevate the clinical efficacy of immediate loading in anterior implants. METHODS: Forty eight implants were placed in 33 patients and the implants were immediately loaded to provide support for fixed provisional prosthesis within 3-6 months. Then, metal-ceramic crowns were restored. The patients were revisited every 12 months after restoration. RESULTS: The follow-up period was 3 to 50 months. All cases achieved good clinical efficacy. CONCLUSION: Clinical studies on the placement of immediate restoration in anterior teeth have revealed predictable results.

[Clinical study of maxillary sinus floor elevation with simultaneous placement of implants from the top of alveoli].

PURPOSE: To evaluate the clinical results of maxillary sinus floor elevation technique with bone condensers on implantation. METHODS: 104 patients underwent maxillary sinus floor elevation and 126 implants were inserted and restored. Clinical examination and radiographs were conducted. Spiral CT scanning and three-dimensional reconstruction was performed among 30 cases during follow-up. RESULTS: All the patients with 9.16 mm (5-11 mm) height of residual bone in the posterior maxilla underwent sinus floor elevation with simultaneous implant placement using bone condensers. The elevation height was 2-6 mm. The follow-up time was 16-82 months. No sinus complication was observed during the follow-up period. The survival rate was 100%. Spiral CT scanning and three-dimensional reconstruction showed that dental implants were submerged in the alveoli around, their tops were covered with bone. CONCLUSIONS: With bone condensers, maxillary sinus floor elevation with simultaneous placement of implants from the top of alveoli was a predictable and safe technique. There were no implants loose or lost, no clinical complaint of maxillary sinus area, and X-ray examination showed well osseointegration.

[Osteoma in the soft palate: report of one case and review of the literature].

Osteoma is a benign tumor, which is composed of mature differentiated bone tissue and derived from osteoplast in periosteum endothecium. Osteomas is common in the bone in clinic, however, osteoma in the soft tissue is distinctly rare. Clinically, the lesion presents as hard, slowly growing mass with clear border. This article reported a case with soft palate osteoma. The clinical manifestation, differential diagnosis, pathologic diagnosis and treatment were discussed. Surgical resection with postoperative follow-up is suggested as the main treatment for this disease.

[Resection of carotid body tumor under interrupted block of common carotid artery].

7 patients with carotid body tumor (CBT) were evaluated by DSA preoperatively. Carotid artery (CA) blocking test was carried out under local anesthesia before operation. With CA blocked temporarily, tumors were resected under general anesthesia after the test was normal. Meanwhile some cases underwent restoration with CA repair, end-to-end anastomosis or artificial vascular grafting. No case underwent internal bypass. CA was blocked 2 to 4 times in operation. The average blocking time of CA was 22 minutes and the longest blocking time of that reached 28 minutes. The average blood loss of cases without embolization preoperatively was 1100 ml, cases with embolization was 480 ml. 3 cases had nerve complications. DSA is of important value in the diagnosis and treatments of CBT. Temporary blocking artery method can help to judge when to use internal bypass, make operation easy, decrease blood loss and nerve complications.

[Applied anatomy of adult mandibular ramus].

OBJECTIVE: To study applied anatomy of adult mandibular ramus and condyle. METHODS: Observation and measurement were made on 16 adult mandibular rami and condyles. RESULTS: Thickness became gradually greater within 15 mm from the back edge of ramus. Some adult mandibular rami had no spongy bone at the level of 10 mm above mandibular foramen. CONCLUSIONS: These date are very important for application of lag screw osteosynthesis in condylar fracture.

[Maxillary sinus lifting and simultaneously placement of implants from the top of alveoli].

OBJECTIVE: To study the effect of maxillary sinus floor elevation by the Frialit-2 Bone Condenser for implantation. METHODS: 11 patients underwent sinus floor lift by The Frialit-2 Bone Condenser and were inserted 14 implants. The time of following up was 10 - 21 months. RESULTS: There were no implant loose or lost, no clinical complaint of maxillary sinus area, and X-ray exam showed well osseointegration. CONCLUSIONS: The Frialit-2 bone condenser can be used for lifting sinus floor, and the sinus elevation without lateral access allows the insertion of implants with no additional surgical stress for the patients.