Faculty Bibliography

OBJECTIVES/HYPOTHESIS/OBJECTIVE:Various animal models have been employed to investigate vocal fold (VF) and phonatory function. However, biomechanical testing techniques to characterize vocal fold structural properties vary and have not compared critical properties across species. We adapted a nondestructive, automated indentation mapping technique to simultaneously quantify VF structural properties (VF cover layer and intact VF) in commonly used species based on the hypothesis that VF biomechanical properties are largely preserved across species. STUDY DESIGN/METHODS:Ex vivo animal model. METHODS:Canine, leporine, and swine larynges (n = 4 each) were sagittally bisected, measured, and subjected to normal indentation mapping (indentation at 0.3 mm; 1.2 mm/s) with a 2-mm spherical indenter to quantify normal force along the VF cover layer, structural stiffness, and displacement at 0.8 mN; two-dimensional maps of the free VF edge through the conus elasticus were created for these characterizations. RESULTS:Structural stiffness was 7.79 gf/mm (0.15-74.55) for leporine, 2.48 gf/mm (0.20-41.75) for canine, and 1.45 gf (0.56-4.56) for swine. For each species, the lowest values were along the free VF edge (mean ± standard deviation; leporine: 0.40 ± 0.21 gf/mm, canine: 1.14 ± 0.49 gf/mm, swine: 0.89 ± 0.28 gf/mm). Similar results were obtained for the cover layer normal force at 0.3 mm. On the free VF edge, mean (standard deviation) displacement at 0.08 gf was 0.14 mm (0.05) in leporine, 0.11 mm (0.03) in canine, and 0.10 mm (0.02) in swine. CONCLUSIONS:Automated indentation mapping yielded reproducible biomechanical property measurement of the VF cover and intact VF. Divergent VF structural properties across canine, swine, and leporine species were observed. LEVEL OF EVIDENCE/METHODS:NA. Laryngoscope, 2018.

This study sought to qualitatively and quantitatively evaluate the effect of osteotomy preparation by conventional (control group) or OD (OD group) instrumentation on osteotomy healing. An incision of 10 cm was made in the anteroposterior direction over the hip in five sheep, and 15 osteotomies were prepared in the left ilium of the sheep (n = 3/sheep). Three different instrumentation techniques were utilized: (1) conventional/regular drilling (R [recommended by manufacturer]) in a 3-step series of a 2-mm pilot, 3.2-mm, and 3.8-mm twist drills; (2) OD clockwise (OD-CW) drilling with Densah Bur (Versah) 2.0-mm pilot, 2.8-mm, and 3.8-mm multi-fluted tapered burs; and (3) OD counterclockwise (OD-CCW) drilling with Densah Bur 2.0-mm pilot, 2.8-mm, and 3.8-mm multi-fluted tapered burs. Drilling was performed at 1,100 rpm with saline irrigation. Qualitative histomorphometric analysis of the osteotomies after 6 weeks did not show any healing impairment due to the instrumentation. Histologic analysis shows bone remodeling and growth in all samples, irrespective of osteotomy preparation technique, with the presence of bone chips observed along the length of the osteotomy wall in sites subjected to osseodensification drilling.

We evaluate bone remodeling and prostheses survival of immediately provisionalized with occlusal loading and delayed loading (DL) single implants placed in the posterior region after 1-yr follow-up in dental practices. Included in the study are patients selected to receive one regular implant (4 × 10 mm) for single tooth replacement in healed ridge sockets in the mandible and maxilla. Implants are immediately loaded or delayed functionally loaded with metal ceramic crowns, depending on peak insertion torque value. All implants are clinically and radiographically evaluated at T1, immediately postoperatively; T2, 60 d; T3, 180 d; and T4, 360 d. Measurements between implant platform and top of alveolar bone crest at distal and mesial areas are performed using periapical radiographs. Data are statistically evaluated through two-way repeated measures of analysis of variance following post hoc comparisons using the Tukey test (p < 0.05). Ten specialists working in ten different practices treat 36 patients who receive one implant each with internal conical connection (hybrid implant system, 4 × 10 mm) (Emfils; Itu, Brazil). Results show that bone-level alterations in immediate (IM; 0.56 mm; confidence interval [CI]: ± 0.21 mm) and delayed (0.65 mm; CI: ± 0.19 mm) groups are not significantly different (p = 0.515) during the course of the 1-yr observation period. In both groups, statistically significant progressive bone-level remodeling occurs through the evaluated follow-up time points (p < 0.047). All prostheses are rated "alpha," presenting 100% success at 1-yr follow-up. The loading method does not influence bone-remodeling levels around IM or DL at the posterior region after 1-yr follow-up. No prostheses complications are reported.

We describe the retrieval of a dental implant device that had been successfully osseointegrated for more than 4 years. After obtaining an informed patient consent, the device was retrieved for retreatment purposes from its position in a β-tricalcium phosphate (β-TCP) grafted sinus floor. The sinus floor augmentation, using β-TCP, had been performed in conjunction with the original implant placement, which in turn enabled the histological evaluation of specific regions of interest that were comprised of either grafted or native bone. Radiographs documented the rehabilitated area before and after grafting. The osteogenic events that occurred during the 4-yr-period depict the interplay of implant, synthetic graft material, and native bone in a dynamic process of osteogenesis, ongoing bone maturation, and remodeling that led to the development of haversian-like bone morphology. Two distinct areas were observed histologically, wherein osteointegration occurred uneventfully in both native bone and areas of grafted bone. Of particular interest was the presence of multiple remodeling sites of lamellar bone that could be seen between the plateaus-healing chambers-in which bone eventually evolved into a haversian cortical-like configuration.

This study evaluates the influence of two surface physicochemical modifications on osseointegration parameters of a healing chamber implant design. We examine dental implants with internal and external trapezoidal threads that have the following surface modifications: dual acid etching (DAE) and nano-hydroxyapatite (HA) coating over DAE surface (Nano). We installed implants in the right ilium of sheep and conducted histologic/metric analyses after 3 and 12 wk in vivo. We quantified the percentage of bone-to-implant contact (%BIC) and bone area fraction occupancy (%BAFO) within implant threads. Histologic micrographs indicate early bone formation within the healing chambers of implants with Nano surface relative to DAE surface. Histomorphometric analysis demonstrates there to be no significant differences in %BIC between 3 and 12 wk (p = 0.298). Compared to DAE, Nano shows more bone formation in contact with implant, regardless of time (p < 0.025). We observe > %BAFO at 12 wk relative to 3 wk, which differs significantly for Nano (p < 0.038). Implant surface treatment affects the amounts of bone formation within healing chambers, with Nano significantly outperforming DAE at 12 wk (p < 0.025). Nano presents a synergistic effect with implant design, improving osseointegration parameters.

OBJECTIVES/OBJECTIVE:To evaluate and compare the outcomes of shear (S) and microtensile (μT) bond strength tests of CAD/CAM fiber-reinforced composite (FRC) to dentin. Aging with either fatigue or thermocycling were conducted for comparison with baseline microtensile group. METHODS:CAD/CAM FRC (Trinia, Bicon LLC, Boston, USA) blocks were milled to 3-mm diameter cylinders for shear and to blocks (5×5×5mm) for μT. Sixty extracted human molars were flattened to obtain dentin surfaces and randomly divided in four groups (n=15): (1) SC: samples tested in shear 24h after bonding; (2) μTC: samples tested in μT 24h after bonding); (3) μTF: samples submitted to mechanical fatigue prior to μT test, and; (4) μTT: thermocycling prior to μT test. Bonding system was applied onto the FRC material (Cera-Resin Bond, CRB, Shofu Dental, Kyoto, Japan). A conventional three-step adhesive system (All-bond 3, Bisco, Schaumburg, USA) was use with a self-cure resin cement (C&B resin cement, Bisco, Schaumburg, USA). Bond strength tests were conducted at 0.75mm/min and data analyzed using Weibull distribution (p<0.05). RESULTS:Weibull contour plots showed a significantly lower characteristic strength (η) and Weibull modulus (m) for SC (η=6.9MPa and m=1.4) compared to μTC (η=20.9MPa and m=4.5). Fatigued and thermocycled μT groups presented significantly reduced characteristic strength (η=3.1MPa and η=4.1MPa, respectively) compared to μTC. Weibull modulus was significantly reduced only for SC and μTF groups compared μTC. Failure predominantly occurred at the cement/FRC interface. SIGNIFICANCE/CONCLUSIONS:FRC bonded to dentin samples presented lower Weibull modulus and characteristic bond strength when immediately tested in shear compared to microtensile. Aging through thermocycling or mechanical fatigue significantly reduced the characteristic strength in microtensile testing, with the majority of failures emerging between restoration material and cement interface.