Statement of Problem: The use of osseointegrated implants as a foundation for the prosthetic replacement of missing teeth has become widespread in the last decade. Owing to the remarkable success of dental implants, there has been growing interest in identifying the factors associated with implant failure. Given the well-documented deleterious effect of smoking on wound healing after tooth extraction and its association with poor quality bone and periodontal disease, a negative effect of tobacco use on implant success is to be expected. Purpose: To establish the relationship between smoking and implant-related surgical procedures (i.e, sinus lift procedures, bone grafts and dental implants), including the incidence of complications related to these procedures and the long-term survival and success rates of dental implants among smokers and nonsmokers based on relevant literature. Materials and Methods: Relevant clinical studies published in English between 1990 and 2006 were reviewed. The articles were located through Medline and, manually, through the references of peer-reviewed literature. This was supplemented with a hand search of selected dental journals and text books. Results: The majority of the past and current literature implicates smoking as one of the prominent risk factors affecting the success rate of dental implants with only a handful of studies failing to establish a connection. Most of the studies report the failure rate of implants in smokers as being more than twice that in nonsmokers. These findings are difficult to ignore. There is a statistically significant difference between smokers and nonsmokers in the failure rates of dental implants. Smoking also has a strong influence on the complication rates of implants: it causes significantly more marginal bone loss after implant placement, it increases the incidence of peri-implantitis and affects the success rates of bone grafts. The failure rate of implants placed in grafted maxillary sinuses of smokers is again more than twice that seen in nonsmokers. Conclusion: Smokers have higher failure rates and complications following dental implantation and implant-related surgical procedures. The failure rate of implants placed in grafted maxillary sinuses of smokers is more than twice that seen in nonsmokers.

Mirza Rustum Baig, BDS, MDS: Purpose: Because there is a paucity of clear-cut evidence regarding which materials and techniques are most accurate for complete-arch, multiple-implant impressions, the current study sought to analyze the data and draw useful conclusions based on the evidence for application in clinical practice. Materials and Methods: Relevant studies published between 1990 and December 2012 were included in the review. The articles were located through PubMed and manually through reviewing references in the literature. Papers examining implant impression accuracy in completely edentulous arches (three or more implants) were included. Clinical case reports, technique articles, abstracts, and review papers were excluded. Results: One of the 34 studies selected for evaluation was clinical; the remaining 33 were in vitro investigations. Ten studies compared polyvinyl siloxane (PVS) and polyether (PE); eight found that these were statistically equal in terms of impression accuracy. The splint effect was examined by 24 studies; 10 failed to observe any differences between splinted and nonsplinted impressions, whereas 7 (> 25%) showed that the splinted technique was better than the nonsplinted technique. Thirteen studies investigated the differences between pickup and transfer impression techniques; six favored pickup over transfer, and five found insignificant differences between the techniques. The effect of nonparallel implants on edentulous multiple-implant impression accuracy was examined by only two studies. Significant differences in accuracy were observed for 15 degrees of angulation. Conclusion: Most of the evidence supports PVS and PE as the most accurate impression materials for edentulous multiple-implant situations, with no clear advantage of either. Conflicting evidence exists regarding the most accurate impression technique (splinted/nonsplinted, pickup/transfer), and no clear recommendation can be made. Inadequate research exists regarding several other factors that might affect edentulous implant impression accuracy. There is a lack of clinical research to support in vitro findings.

Fit accuracy and fracture strength of milled monolithic zirconia (Zi) and zirconia-reinforced lithium silicate (ZLS) crowns are important parameters determining the success of these restorations. This study aimed to evaluate and compare the marginal and internal fit of monolithic Zi and ZLS crowns, along with the fracture load, with and without mechanical aging. Thirty-two stone dies acquired from a customized master metal molar die were scanned, and ceramic crowns (16 Zi Ceramill Zolid HT⁺ and 16 ZLS Vita Suprinity) were designed and milled. Absolute marginal discrepancies (AMD), marginal gaps (MG), and internal gaps (IG) of the crowns, in relation to the master metal die, were evaluated using x-ray nanotomography (n = 16). Next, thirty-two metal dies were fabricated based on the master metal die, and crowns (16 Zi; 16 ZLS) cemented and divided into four groups of eight each; eight Zi with mechanical aging (MA), eight Zi without mechanical aging (WMA), eight ZLS (MA), and eight ZLS (WMA). Two groups of crowns (Zi-MA; ZLS-MA) were subjected to 500,000 mechanical cycles (200 ± 50 N, 10 Hz) followed by axial compressive strength testing of all crowns, until failure, and the values were recorded. Independent sample t tests (α = 0.05) revealed no significant differences between Zi and ZLS crowns (p > 0.05); for both internal and marginal gaps, however, there were significant differences in AMD (p < 0.005). Independent samples Mann–Whitney U and Kruskal–Wallis tests revealed significant differences between the two materials, Zi and ZLS, regardless of fatigue loading, and for the individual material groups based on aging (α = 0.05). Multiple comparisons using Bonferroni post-hoc analysis showed significant differences between Zi and ZLS material groups, with or without aging. Within the limitations of this study, the ZLS crown fit was found to be on par with Zi, except for the AMD parameter. As regards fracture resistance, both materials survived the normal range of masticatory forces, but the Zi crowns demonstrated greater resistance to fracture. The monolithic Zi and ZLS crowns seem suitable for clinical application, based on the fit and fracture strength values obtained.

Successful placement of dental implants in extraction sockets has been reported in the literature. There are numerous practical considerations in relation to immediate implant placement that make the procedure more complex as compared with placement in healed extraction sites. A short review of the literature is presented to understand the scientific principles and controversies related to immediate implants. This is followed by a presentation of 3 completed cases of immediate implants. Some of the important practical considerations in relation to immediate implant placement are also highlighted.