Ridge alterations post-extraction in the esthetic zone: a 3D analysis with CBCT

Dimensional alterations of the facial bone wall following tooth extractions in the esthetic zone have a profound effect on treatment outcomes. This prospective study in 39 patients is the first to investigate three-dimensional (3D) alterations of facial bone in the esthetic zone during the initial 8 wks following flapless tooth extraction. A novel 3D analysis was carried out, based on 2 consecutive cone beam computed tomographies (CBCTs). A risk zone for significant bone resorption was identified in central areas, whereas proximal areas yielded only minor changes. Correlation analysis identified a facial bone wall thickness of ≤ 1 mm as a critical factor associated with the extent of bone resorption. Thin-wall phenotypes displayed pronounced vertical bone resorption, with a median bone loss of 7.5 mm, as compared with thick-wall phenotypes, which decreased by only 1.1 mm. For the first time, 3D analysis has allowed for documentation of dimensional alterations of the facial bone wall in the esthetic zone of humans following extraction. It also characterized a risk zone prone to pronounced bone resorption in thin-wall phenotypes. Vertical bone loss was 3.5 times more severe than findings reported in the existing literature.

Piezoelectric alveolar ridge-splitting technique with simultaneous implant placement: a cohort study with 2-year radiographic results

PURPOSE Extended grafting procedures in atrophic ridges are invasive and time-consuming and increase cost and patient morbidity. Therefore, ridge-splitting techniques have been suggested to enlarge alveolar crests. The aim of this cohort study was to report techniques and radiographic outcomes of implants placed simultaneously with a piezoelectric alveolar ridge-splitting technique (RST). Peri-implant bone-level changes (ΔIBL) of implants placed with (study group, SG) or without RST (control group, CG) were compared. MATERIALS AND METHODS Two cohorts (seven patients in each) were matched regarding implant type, position, and number; superstructure type; age; and gender and received 17 implants each. Crestal implant bone level (IBL) was measured at surgery (T0), loading (T1), and 1 year (T2) and 2 years after loading (T3). For all implants, ΔIBL values were determined from radiographs. Differences in ΔIBL between SG and CG were analyzed statistically (Mann-Whitney U test). Bone width was assessed intraoperatively, and vertical bone mapping was performed at T0, T1, and T3. RESULTS After a mean observation period of 27.4 months after surgery, the implant survival rate was 100%. Mean ΔIBL was -1.68 ± 0.90 mm for SG and -1.04 ± 0.78 mm for CG (P = .022). Increased ΔIBL in SG versus CG occurred mainly until T2. Between T2 and T3, ΔIBL was limited (-0.11 ± 1.20 mm for SG and -0.05 ± 0.16 mm for CG; P = .546). Median bone width increased intraoperatively by 4.7 mm. CONCLUSIONS Within the limitations of this study, it can be suggested that RST is a well-functioning one-stage alternative to extended grafting procedures if the ridge shows adequate height. ΔIBL values indicated that implants with RST may fulfill accepted implant success criteria. However, during healing and the first year of loading, increased IBL alterations must be anticipated.

Does cigarette smoking modify the association between change in body mass index during young adulthood and risk of coronary mortality during middle-age in men? Twenty-five year follow-up results from the Chicago Western Electric Study

Many persons in the U.S. gain weight during young adulthood, and the prevalence of obesity has been increasing among young adults. Although obesity and physical inactivity are generally recognized as risk factors for coronary heart disease (CHD), the magnitude of their effect on risk may have been seriously underestimated due to failure to adequately handle the problem of cigarette smoking. Since cigarette smoking causes weight loss, physically inactive cigarette smokers may remain relatively lean because they smoke cigarettes. We hypothesize cigarette smoking modifies the association between weight gain during young adulthood and risk of coronary heart disease during middle age, and that the true effect of weight gain during young adulthood on risk of CHD can be assessed only in persons who have not smoked cigarettes. Specifically, we hypothesize that weight gain during young adulthood is positively associated with risk of CHD during middle-age in nonsmokers but that the association is much smaller or absent entirely among cigarette smokers. The purpose of this study was to test this hypothesis. The population for analysis was comprised of 1,934 middle-aged, employed men whose average age at the baseline examination was 48.7 years. Information collected at the baseline examinations in 1958 and 1959 included recalled weight at age 20, present weight, height, smoking status, and other CHD risk factors. To decrease the effect of intraindividual variation, the mean values of the 1958 and 1959 baseline examinations were used in analyses. Change in body mass index ($\Delta$BMI) during young adulthood was the primary exposure variable and was measured as BMI at baseline (kg/m$\sp2)$ minus BMI at age 20 (kg/m$\sp2).$ Proportional hazards regression analysis was used to generate relative risks of CHD mortality by category of $\Delta$BMI and cigarette smoking status after adjustment for age, family history of CVD, major organ system disease, BMI at age 20, and number of cigarettes smoked per day. Adjustment was not performed for systolic blood pressure or total serum cholesterol as these were regarded as intervening variables. Vital status was known for all men on the 25th anniversary of their baseline examinations. 705 deaths (including 319 CHD deaths) occurred over 40,136 person-years of experience. $\Delta$BMI was positively associated with risk of CHD mortality in never-smokers, but not in ever-smokers (p for interaction = 0.067). For never-smokers with $\Delta$BMI of stable, low gain, moderate gain, and high gain, adjusted relative risks were 1.00, 1.62, 1.61, and 2.78, respectively (p for trend = 0.010). For ever-smokers, with $\Delta$BMI of stable, low gain, moderate gain, and high gain, adjusted relative risks were 1.00, 0.74, 1.07, and 1.06, respectively (p for trend = 0.422). These results support the research hypothesis that cigarette smoking modifies the association between weight gain and CHD mortality. Current estimates of the magnitude of effect of obesity and physical inactivity on risk of coronary mortality may have been seriously underestimated due to inadequate handling of cigarette smoking. ^

The beginnings of the Chicago Sinai congregation : a contribution to the inner history of American judaism

by B. Felsenthal

Evaluation of a new experimental model to study bone healing after ridge expansion with simultaneous implant placement--a pilot study in minipigs.

OBJECTIVE To evaluate the suitability of a minipig model for the study of bone healing and osseointegration of dental implants following bone splitting and expansion of narrow ridges. MATERIAL AND METHODS In four minipigs, the mandibular premolars and first molars were extracted together with removal of the buccal bone plate. Three months later, ridge splitting and expansion was performed with simultaneous placement of three titanium implants per quadrant. On one side of the mandible, the expanded bone gap between the implants was filled with an alloplastic biphasic calcium phosphate (BCP) material, while the gap on the other side was left unfilled. A barrier membrane was placed in half of the quadrants. After a healing period of 6 weeks, the animals were sacrificed for histological evaluation. RESULTS In all groups, no bone fractures occurred, no implants were lost, all 24 implants were osseointegrated, and the gap created by bone splitting was filled with new bone, irrespective of whether BCP or a barrier membrane was used. Slight exposure of five implants was observed, but did not lead to implant loss. The level of the most coronal bone-to-implant contact varied without being dependent on the use of BCP or a barrier membrane. In all groups, the BCP particles were not present deep in the bone-filled gap. However, BCP particles were seen at the crestal bone margin, where they were partly integrated in the new bone. CONCLUSIONS This new minipig model holds great promise for studying experimental ridge splitting/expansion. However, efforts must be undertaken to reduce implant exposure and buccal bone resorption.

Horizontal ridge augmentation in conjunction with or prior to implant placement in the anterior maxilla: a systematic review.

PURPOSE To systematically review clinical studies examining the survival and success rates of implants in horizontal ridge augmentation, either prior to or in conjunction with implant placement in the anterior maxilla. MATERIALS AND METHODS A literature search was undertaken up to September 2012 including clinical studies in English with ≥ 10 consecutively treated patients and a mean follow-up of at least 12 months. Two reviewers screened the pertinent articles and extracted the data. Key words focused on the outcome parameters (implant success, implant survival, horizontal bone gain, and intra- and postoperative complications) in studies utilizing either a simultaneous approach (ridge augmentation performed at the time of implant placement) or a staged approach (ridge augmentation performed prior to implant placement) were analyzed. RESULTS A total of 13 studies met the inclusion criteria, with 2 studies in the simultaneous group and 11 studies in the staged group. In the simultaneous group, survival rates of implants were 100% in both studies, with one study also reporting a 100% implant success rate. No data on horizontal bone gain were available. In the staged group, success rates of implants placed in horizontally augmented ridges ranged from 96.8% to 100% (two studies), and survival rates ranged from 93.5% to 100% (five studies). However, follow-up periods differed widely (up to 4.1 years). Mean horizontal bone gain determined at reentry (implant placement) ranged from 3.4 to 5.0 mm with large overall variations (0 to 9.8 mm, five studies). Intraoperative complications were not reported. Postsurgical complications included mainly mucosal dehiscences (five studies), and, occasionally, complete failures of block grafts were described in one study. CONCLUSIONS Staged and simultaneous augmentation procedures in the anterior maxilla are both associated with high implant success and survival rates. The level of evidence, however, is better for the staged approach than for the simultaneous one.

Sinus floor elevation: comparison of the presurgical ridge height of different techniques - a retrospective analysis.

Purpose: Radiographic evaluation of the vertical presurgical ridge height (PRH) of implants, placed using the transcrestal or lateral window sinus floor elevation (SFE) technique in edentulous and partially dentate patients. The 5-year implant survival rate and the prosthetic restoration following the SFE procedure were also evaluated. Methods: Radiographs of 83 tapered implants placed in 53 patients were available for analysis. 31 implants were placed by the transcrestal and 52 were placed by the lateral window technique. In the lateral window technique 21 implants were placed simultaneously, 31 in a staged approach. The PRH, the implant survival rate after five years and the prosthetic restoration were evaluated with respect to the chosen SFE procedure. Results: The PRH was significantly higher for the transcrestal than both lateral window techniques, mean values: 8.0 ± 2.7 mm (transcrestal); 4.2 ± 2.6 mm (lateral simultaneous); 4.5 ± 2.8 mm (lateral staged). There was no significant difference of PRH between the edentulous and partially dentate patients. All loaded implants were stable, resulting in a 100% implant survival rate after 5 years. There was a small overproportion of single crown restorations in the transcrestal SFE technique group. Conclusion: This study confirms that the transcrestal technique is chosen, when a higher PRH is available. The choice of a simultaneous or staged lateral window approach is mainly dependent on the expected primary stability of the implant and not only on the PRH. SFE procedures are a safe and predictable treatment option to place implants in the vertical atrophic maxilla.

Bone loss after ridge expansion with or without reflection of the periosteum.

OBJECTIVE To evaluate the role of the periosteum in preserving the buccal bone after ridge splitting and expansion with simultaneous implant placement. MATERIAL AND METHODS In 12 miniature pigs, the mandibular premolars and first molars were removed together with the interdental bone septa and the buccal bone. Three months later, ridge splitting and expansion of the buccal plate was performed with simultaneous placement of two titanium implants per quadrant. Access by a mucosal flap (MF) was prepared on test sides, while a mucoperiosteal flap (MPF) with complete denudation of the buccal bone was increased on control sides. After healing periods of six and 12 weeks, the animals were sacrificed for histologic and histometric evaluation. RESULTS In the MF group, all 16 implants were osseointegrated, while in the MPF group, four of 16 implants were lost. Noticeable differences of bone levels on the implant surface and of the bone crest (BC) were found between the MF and the MPF group. Buccally after 6 weeks, the median distance between the implant shoulder (IS) and the coronal-most bone on the implant (cBIC) was for the MF group -1.42 ± 0.42 mm and for the MPF group -4.80 ± 2.72 mm (P = 0.15). The median distance between the IS and the buccal BC was -1.24 ± 0.51 mm and -2.78 ± 1.98 mm (P = 0.12) for the MF and MPF group, respectively. After 12 weeks, median IS-cBIC was -2.12 ± 0.84 mm for MF and -7.19 mm for MPF, while IS-BC was -2.08 ± 0.79 mm for MF and -5.96 mm for MPF. After 6 weeks, the median buccal bone thickness for MF and MPF was 0.01 and 0 mm (P < 0.001) at IS, 1.48 ± 0.97 mm and 0 ± 0.77 mm (P = 0.07) at 2 mm apical to IS, and 2.12 ± 1.19 mm and 1.72 ± 01.50 mm (P = 0.86) at 4 mm apical to IS, respectively. After 12 weeks, buccal bone thickness in the MF group was 0 mm at IS, 0.21 mm at 2 mm apical to IS, and 2.56 mm at 4 mm apical to IS, whereas complete loss of buccal bone was measured from IS to 4 mm apical to IS for the MPF group. CONCLUSIONS In this ridge expansion model in miniature pigs, buccal bone volume was significantly better preserved when the periosteum remained attached to the bone.

Partial lateralization of the nasopalatine nerve at the incisive foramen for ridge augmentation in the anterior maxilla prior to placement of dental implants: a retrospective case series evaluating self-reported data and neurosensory testing

The objective of this study was to assess implant therapy after a staged guided bone regeneration procedure in the anterior maxilla by lateralization of the nasopalatine nerve and vessel bundle. Neurosensory function following augmentative procedures and implant placement, assessed using a standardized questionnaire and clinical examination, were the primary outcome variables measured. This retrospective study included patients with a bone defect in the anterior maxilla in need of horizontal and/or vertical ridge augmentation prior to dental implant placement. The surgical sites were allowed to heal for at least 6 months before placement of dental implants. All patients received fixed implant-supported restorations and entered into a tightly scheduled maintenance program. In addition to the maintenance program, patients were recalled for a clinical examination and to fill out a questionnaire to assess any changes in the neurosensory function of the nasopalatine nerve at least 6 months after function. Twenty patients were included in the study from February 2001 to December 2010. They received a total of 51 implants after augmentation of the alveolar crest and lateralization of the nasopalatine nerve. The follow-up examination for questionnaire and neurosensory assessment was scheduled after a mean period of 4.18 years of function. None of the patients examined reported any pain, they did not have less or an altered sensation, and they did not experience a "foreign body" feeling in the area of surgery. Overall, 6 patients out of 20 (30%) showed palatal sensibility alterations of the soft tissues in the region of the maxillary canines and incisors resulting in a risk for a neurosensory change of 0.45 mucosal teeth regions per patient after ridge augmentation with lateralization of the nasopalatine nerve. Regeneration of bone defects in the anterior maxilla by horizontal and/or vertical ridge augmentation and lateralization of the nasopalatine nerve prior to dental implant placement is a predictable surgical technique. Whether or not there were clinically measurable impairments of neurosensory function, the patients did not report them or were not bothered by them.

Henry Haynie [Illustration] : (Redakteur des "Chicago Herold")

Friedrich Beer

Mortgage Lending in Chicago and Los Angeles: A Paired Testing Study of the Pre-Application Process

This paper analyzes data from a recently completed study of discrimination against African-American and Hispanic homebuyers when they visit mortgage lending institutions in two major metropolitan markets to make pre-application inquiries. It represents the first application of paired testing to rigorously measure discrimination in the mortgage lending process. The paired tests isolated significant levels of differential treatment on the basis of race and ethnicity in Chicago with African Americans and Hispanics receiving less information and assistance than comparable whites. Adverse treatment of African-Americans and Hispanics is also observed in Los Angeles for specific treatments, but the overall pattern of treatment observed did not differ statistically from equal treatment. Multivariate analyses for Chicago indicate that large lenders treat minorities more favorably than small lenders and that lenders with substantial numbers of applications from African-Americans treat African Americans more favorably than lenders with predominantly white application pools.

Das unzerstörbare Meisterwerk : Aus: A thousand and one afternoons in Chicago [1922]

Ella Kronfeld

Tuberkulose-Sterblichkeit in Chicago

Hoppe