Faculty Bibliography

PURPOSE: Primary stability has been regarded as a key factor to ensure uneventful osseointegration of dental implants. Such stability is often achieved by placing implants in undersized drilled bone. The present study evaluated the effect of drilling dimensions in insertion torque and early implant osseointegration stages in a beagle dog model. MATERIALS AND METHODS: Six beagle dogs were acquired and subjected to bilateral surgeries in the radii 1 and 3 weeks before death. During surgery, 3 implants, 4 mm in diameter by 10 mm in length, were placed in bone sites drilled to 3.2 mm, 3.5 mm, and 3.8 mm in diameter. The insertion torque was recorded for all samples. After death, the implants in bone were nondecalcified processed and morphologically and morphometrically (bone-to-implant contact and bone area fraction occupancy) evaluated. Statistical analyses were performed using the Kruskal-Wallis test followed by Dunn's post hoc test for multiple comparisons at the 95% level of significance. RESULTS: The insertion torque levels obtained were inversely proportional to the drilling dimension, with a significant difference detected between the 3.2-mm and 3.8-mm groups (P = .003). Despite a significant increase in the bone-to-implant contact over time in vivo for all groups (P = .007), no effect for the drilling dimension was observed. Additionally, no effect of the drilling dimension and time was observed for the bone area fraction occupancy parameter (P = .31). The initial healing pathways differed between implants placed in bone drilled to different dimensions. CONCLUSIONS: Although different degrees of torque were observed with different drilling dimensions and these resulted in different healing patterns, no differences in the histometrically evaluated parameters were observed.

OBJECTIVES: This study compared the biomechanical fixation and bone-to-implant contact (BIC) of implants with different surfaces treatment (experimental - resorbable blasting media-processed nanometer roughness scale surface, and control - dual acid-etched) in a dog model. MATERIAL AND METHODS: Surface characterization was made in six implants by means of scanning electron microscopic imaging, atomic force microscopy to evaluate roughness parameters, and X-ray photoelectron spectroscopy (XPS) for chemical assessment. The animal model comprised the bilateral placement of control (n=24) and experimental surface (n=24) implants along the proximal tibiae of six mongrel dogs, which remained in place for 2 or 4 weeks. Half of the specimens were biomechanically tested (torque), and the other half was subjected to histomorphologic/morphometric evaluation. BIC and resistance to failure measures were each evaluated as a function of time and surface treatment in a mixed model ANOVA. RESULTS: Surface texturing was significantly higher for the experimental compared with the control surface. The survey XPS spectra detected O, C, Al, and Ti at the control group, and Ca ( approximately 0.2- 0.9%) and P ( approximately 1.7- 4.1%) besides O, C, Al, and Ti at experimental surfaces. While no statistical difference in BIC was found between experimental and control surfaces or between 2 and 4 weeks in vivo, both longer time and use of experimental surface significantly increased resistance to failure. CONCLUSIONS: The experimental surface resulted in enhanced biomechanical fixation but comparable BIC relative to control, suggesting higher bone mechanical properties around the experimental implants.

OBJECTIVES: To compare the biomechanical fixation and histomorphometric parameters between two implant surfaces: non-washed resorbable blasting media (NWRBM) and alumina-blasted/acid-etched (AB/AE), in a dog model. MATERIAL AND METHODS: The surface topography was assessed by scanning electron microscopy, optical interferometry and chemistry by X-ray photoelectron spectroscopy (XPS). Six beagle dogs of approximately 1.5 years of age were utilized and each animal received one implant of each surface per limb (distal radii sites). After a healing period of 3 weeks, the animals were euthanized and half of the implants were biomechanically tested (removal torque) and the other half was referred to nondecalcified histology processing. Histomorphometric analysis considered bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO). Following data normality check with the Kolmogorov-Smirnov test, statistical analysis was performed by paired t-tests at 95% level of significance. RESULTS: Surface roughness parameters S(a) (average surface roughness) and S(q) (mean root square of the surface) were significantly lower for the NWRBM compared with AB/AE. The XPS spectra revealed the presence of Ca and P in the NWRBM. While no significant differences were observed for both BIC and BAFO parameters (P>0.35 and P>0.11, respectively), a significantly higher level of torque was observed for the NWRBM group (P=0.01). Bone morphology was similar between groups, which presented newly formed woven bone in proximity with the implant surfaces. CONCLUSION: A significant increase in early biomechanical fixation was observed for implants presenting the NWRBM surface.

The Doctor of Public Health (DrPH) Core Competency Model aspires to rigorously train future leaders of public health practice to direct and advance societal efforts that address socially rooted causes of health and illness. Although there is no proven formula for success, 3 principles derived from practice may guide the way forward: (1) institutionalize mutual learning and reciprocity between schools of public health and public health agencies and organizations, (2) capitalize on the full resources of the larger university to enrich the educational experiences of DrPH candidates and public health leaders, and (3) globalize the search for model DrPH programs that may be adapted for US schools. Schools of public health must ensure that DrPH programs gain the status and resources needed to fulfill their societal mandate.

Objectives: As part of ongoing efforts by the Columbia University College of Dental Medicine to devise community-based models of health promotion and care for local residents, we sought to answer the following query: "What contributes to self-rated oral health among community-dwelling older adults?" Methods: The present study is cross sectional in design and centrally concerned with baseline data collected during community-based screenings of adults aged 50 years and older who agreed to participate in the ElderSmile program in northern Manhattan, New York City. The primary outcome measure of interest is self-rated oral health, which was assessed as follows: "Overall, how would you rate the health of your teeth and gums - excellent, good, fair, or poor?" Results: More than a quarter (28.5 percent) of ElderSmile participants aged 50 years and older reported that their oral health was poor. After adjustment for age (in years), place of birth, educational level, and dental insurance status in a logistic regression model, recent visits to the dentist (within the past year versus more than a year ago) contributed to better self-rated oral health and non-Hispanic Black race/ethnicity, dentate (versus edentulous) status, tooth decay as measured by decayed missing filled teeth, and severe periodontal inflammation contributed to worse self-rated oral health in this population. Conclusions: Recent dental care contributed to better self-rated oral health among community-dwelling older adults living in northern Manhattan. Significant gradients were evident in the caries experience and periodontal inflammation of dentate adults by self-rated oral health, suggesting that untreated oral disease contributes to poor self-rated oral health.

Summary Titanium or zirconium computer-aided design/computer-aided manufacturing abutments are now widely used for aesthetic implant treatments; however, information regarding microscopic structural differences that may influence the biological and mechanical outcomes of different implant systems is limited. Therefore, the characteristics of different connection systems were investigated. Optical microscopic observation and scanning electron microscopy showed different characteristics of two internal systems, namely the Astra Tech and the Replace Select system, and for different materials. The scanning electron microscopic observation showed for the Astra Tech that the implant-abutment interface seemed to be completely sealed for both titanium and zirconium abutments, both horizontally and sagittally; however, the first implant-abutment contact was below the fixture top, creating a microgap, and fixtures connected with titanium abutments showed significantly larger values (23.56 mum +/- 5.44 in width, and 168.78 mum +/- 30.39 in depth, P < 0.001). For Replace Select, scanning electron microscopy in the sagittal direction showed that the sealing of titanium and zirconium abutments differed. The seal between the implant-titanium and implant-zirconium abutments seemed to be complete at the butt-joint interface; however, the displacement of the abutment in relation to the fixture in the lateral direction was evident for both abutments with no statistical differences (P > 0.70), creating an inverted microgap. Thus, microscopy evaluation of two commonly used internal systems connected to titanium or zirconium abutments showed that the implant-abutment interface was perfectly sealed under no-loading conditions. However, an inverted microgap was seen in both systems, which may result in bacterial accumulation as well as alteration of stress distribution at the implant-abutment interface.

OBJECTIVES: To evaluate the effect of insertion torque on micromotion to a lateral force in three different implant designs. MATERIAL AND METHODS: Thirty-six implants with identical thread design, but different cutting groove design were divided in three groups: (1) non-fluted (no cutting groove, solid screw-form); (2) fluted (90 degrees cut at the apex, tap design); and (3) Blossom() (Patent pending) (non-fluted with engineered trimmed thread design). The implants were screwed into polyurethane foam blocks and the insertion torque was recorded after each turn of 90 degrees by a digital torque gauge. Controlled lateral loads of 10 N followed by increments of 5 up to 100 N were sequentially applied by a digital force gauge on a titanium abutment. Statistical comparison was performed with two-way mixed model ANOVA that evaluated implant design group, linear effects of turns and displacement loads, and their interaction. RESULTS: While insertion torque increased as a function of number of turns for each design, the slope and final values increased (P<0.001) progressively from the Blossom to the fluted to the non-fluted design (M +/- standard deviation [SD]=64.1 +/- 26.8, 139.4 +/- 17.2, and 205.23 +/- 24.3 Ncm, respectively). While a linear relationship between horizontal displacement and lateral force was observed for each design, the slope and maximal displacement increased (P<0.001) progressively from the Blossom to the fluted to the non-fluted design (M +/- SD=530 +/- 57.7, 585.9 +/- 82.4, and 782.33 +/- 269.4 mum, respectively). There was negligible to moderate levels of association between insertion torque and lateral displacement in the Blossom, fluted and non-fluted design groups, respectively. CONCLUSION: Insertion torque was reduced in implant macrodesigns that incorporated cutting edges, and lesser insertion torque was generally associated with decreased micromovement. However, insertion torque and micromotion were unrelated within implant designs, particularly for those designs showing the least insertion torque.

Widespread recognition of the need to improve the science of published research, as well as the moral and ethical reasons for adequately reporting study results, has spurred recent interest in strengthening journal research reporting through the use of reporting guidelines. Reporting guidelines also provide information for readers to judge study quality. American Journal of Public Health previously adopted the Consolidated Standards of Reporting Trials and Transparent Reporting of Evaluations With Nonrandomized Designs guidelines and recently endorsed the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. In adopting these guidelines, the journal aims to support authors, reviewers, and editors in reporting and evaluating systematic reviews of public health policy and practice priorities. (Am J Public Health. Published online ahead of print March 15, 2012: e1-e5. doi:10.2105/AJPH.2011.300630).