Analysis of the socket bone wall dimensions in the upper maxilla in relation to immediate implant placement

Background: Animal and human researches have shown that immediate implant placement into extraction sockets failed to prevent socket dimensional changes following tooth extraction. It has been suggested that a minimal width of 1–2 mm of buccal bone is necessary to maintain a stable vertical dimension of the alveolar crest. Aim: To determine the dimensions of the bony wall at extraction sites in the esthetic zone (anterior teeth and premolars in the maxilla) and relate it to immediate implant placement. Methods: As part of an ongoing prospective randomized‐controlled multicenter clinical study on immediate implant placement, the width of the buccal and palatal bony walls was recorded at 93 extraction sites. Results: The mean width of the buccal and palatal bony walls was 1 and 1.2 mm, respectively (P<0.05). For the anterior sites (canine to canine), the mean width of the buccal bony wall was 0.8 mm. For the posterior (premolar) sites, it was 1.1 mm (P<0.05). In the anterior sites, 87% of the buccal bony walls had a width ≤1 mm and 3% of the walls were 2 mm wide. In the posterior sites, the corresponding values were 59% and 9%, respectively. Conclusions: If the criterion of a minimal buccal bone width of 2 mm to maintain a stable buccal bony wall is valid, only a limited number of sites in the anterior maxilla display such a clinical situation. The data suggested that in the majority of extraction sites in the anterior maxilla, thin (≤1 mm) buccal walls were present. This, in turn, means that in most clinical situations encountered, augmentation procedures are needed to achieve adequate bony contours around the implant. To cite this article:
Huynh‐Ba G, Pjetursson BE, Sanz M, Cecchinato D, Ferrus J, Lindhe J, Lang NP. Analysis of the socket bone wall dimensions in the upper maxilla in relation to immediate implant placement.
Clin. Oral Impl. Res. 21 , 2010; 37–42.     

A systematic review of the survival and complication rates of implant supported fixed dental prostheses with cantilever extensions after an observation period of at least 5 years

Objective: The aim of this systematic review was to assess the survival rates of short-span implant-supported cantilever fixed dental prostheses (ICFDPs) and the incidence of technical and biological complications after an observation period of at least 5 years.
Material and methods: An electronic MEDLINE search supplemented by manual searching was conducted to identify prospective or retrospective cohort studies reporting data of at least 5 years on ICFDPs. Five- and 10-year estimates for failure and complication rates were calculated using standard or random-effect Poisson regression analysis.
Results: The five studies eligible for the meta-analysis yielded an estimated 5- and 10-year ICFDP cumulative survival rate of 94.3% [95 percent confidence interval (95% CI): 84.1–98%] and 88.9% (95% CI: 70.8–96.1%), respectively. Five-year estimates for peri-implantitis were 5.4% (95% CI: 2–14.2%) and 9.4% (95% CI: 3.3–25.4%) at implant and prosthesis levels, respectively. Veneer fracture (5-year estimate: 10.3%; 95% CI: 3.9–26.6%) and screw loosening (5-year estimate: 8.2%; 95% CI: 3.9–17%) represented the most common complications, followed by loss of retention (5-year estimate: 5.7%; 95% CI: 1.9–16.5%) and abutment/screw fracture (5-year estimate: 2.1%; 95% CI: 0.9–5.1%). Implant fracture was rare (5-year estimate: 1.3%; 95% CI: 0.2–8.3%); no framework fracture was reported. Radiographic bone level changes did not yield statistically significant differences either at the prosthesis or at the implant levels when comparing ICFDPs with short-span implant-supported end-abutment fixed dental prostheses.
Conclusions: ICFDPs represent a valid treatment modality; no detrimental effects can be expected on bone levels due to the presence of a cantilever extension per se .     

A systematic review of the success of sinus floor elevation and survival of implants inserted in combination with sinus floor elevation

Objectives: The objectives of this systematic review were to assess the survival rate of grafts and implants placed with sinus floor elevation.
Material and Methods: An electronic search was conducted to identify studies on sinus floor elevation, with a mean follow-up time of at least 1 year after functional loading.
Results: The search provided 839 titles. Full-text analysis was performed for 175 articles resulting in 48 studies that met the inclusion criteria, reporting on 12,020 implants. Meta-analysis indicated an estimated annual failure rate of 3.48% [95% confidence interval (CI): 2.48%–4.88%] translating into a 3-year implant survival of 90.1% (95% CI: 86.4%–92.8%). However, when failure rates was analyzed on the subject level, the estimated annual failure was 6.04% (95% CI: 3.87%–9.43%) translating into 16.6% (95% CI: 10.9%–24.6%) of the subjects experiencing implant loss over 3 years.
Conclusion: The insertion of dental implants in combination with maxillary sinus floor elevation is a predictable treatment method showing high implant survival rates and low incidences of surgical complications.
The best results (98.3% implant survival after 3 years) were obtained using rough surface implants with membrane coverage of the lateral window.     

Infections and obesity: A multinational epidemiological study

Viral infections have been associated with the aetiology of obesity in animal models. This study investigates the association between 7 serological markers of infections and body mass index (BMI) in a population based sample. Individuals (n=985, mean age 42+/-97 (28-55) y, mean BMI 25.594.2) from Iceland, Sweden and Estonia underwent a structured interview and blood sampling. IgG antibodies were measured against Helicobacter pylori and the cagA protein, hepatitis A virus, Toxoplasma gondii, herpes simplex virus 1, Chlamydia pneumoniae, Epstein-Barr virus and cytomegalovirus. High-sensitive C-reactive protein (CRP) was measured as a marker of systemic inflammation. A significant positive association between being overweight (BMI25 kg/m2) and IgG antibodies was found for Helicobacter pylori (OR 1.86, CI 1.34-2.60) and Chlamydia pneumoniae (OR 1.39, CI 1.03-1.88) and combined seropositivity had synergistic effect (OR 2.54 (1.62-3.97)). CRP was positively related to BMI (pB0.0001), whereas no significant association was found between CRP and IgG antibodies against Helicobacter pylori and/or Chlamydia pneumoniae and CRP. The results suggest that infections with Chlamydia pneumoniae and Helicobacter pylori are both significantly and synergistically associated with overweight and this association is not related to indicators of systemic inflammation.     

Gender differences in the association between C-reactive protein, lung function impairment, and COPD

Individuals with COPD have systemic inflammation that can be assessed by measuring C-reactive protein (CRP). In this paper we evaluated whether CRP is related to COPD, lung function and rate of lung function decline.We included 1237 randomly selected subjects (mean age 42, range 28–56 years) from three centers in the European Community Respiratory Health Survey: Reykjavik, Uppsala and Tartu. CRP was measured at the end of the follow-up (mean 8.3 years) and the values were divided into 4 quartiles.Fifty-three non-asthmatic subjects fulfilled spirometric criteria for COPD (FEV₁/FVC < 70%). COPD occurred more often in the 4th CRP quartile (OR (95% CI) 3.21 (1.13–9.08)) after adjustment for age, gender, body weight and smoking. High CRP levels were related to lower FEV₁ values in both men (−437 (−596, −279) mL) and women (−144 (−243, −44) mL). The negative association between CRP and FEV₁ was significantly larger in men than women (p = 0.04). The decline in FEV₁ was larger (16 (5, 27) mL) in men with high CRP levels whereas no significant association between CRP and FEV₁ decline was found in women.Higher CRP values are significantly associated with COPD and lower lung function in men and women. In men higher CRP values are related to a larger decline in FEV₁.     

Whole-genome shotgun assembly and comparison of human genome assemblies

We report a whole-genome shotgun assembly (called WGSA) of the human genome generated at Celera in 2001. The Celera-generated shotgun data set consisted of 27 million sequencing reads organized in pairs by virtue of end-sequencing 2-kbp, 10-kbp, and 50-kbp inserts from shotgun clone libraries. The quality-trimmed reads covered the genome 5.3 times, and the inserts from which pairs of reads were obtained covered the genome 39 times. With the nearly complete human DNA sequence [National Center for Biotechnology Information (NCBI) Build 34] now available, it is possible to directly assess the quality, accuracy, and completeness of WGSA and of the first reconstructions of the human genome reported in two landmark papers in February 2001 [Venter, J. C., Adams, M. D., Myers, E. W., Li, P. W., Mural, R. J., Sutton, G. G., Smith, H. O., Yandell, M., Evans, C. A., Holt, R. A., et al. (2001) Science 291, 1304–1351; International Human Genome Sequencing Consortium (2001) Nature 409, 860–921]. The analysis of WGSA shows 97% order and orientation agreement with NCBI Build 34, where most of the 3% of sequence out of order is due to scaffold placement problems as opposed to assembly errors within the scaffolds themselves. In addition, WGSA fills some of the remaining gaps in NCBI Build 34. The early genome sequences all covered about the same amount of the genome, but they did so in different ways. The Celera results provide more order and orientation, and the consortium sequence provides better coverage of exact and nearly exact repeats.