Today there are several treatment techniques available to replace a missing tooth. Since the beginning of the 1990s, it has become increasingly common to treat individual tooth loss with dental implants. Important patient factors are survival, success, functionality, aesthetics, oral health and quality of life.

The range of indications and possibilities for implant treatment has broadened compared to the originally proposed treatment indications. A variety of methods, components and materials are available today. Improvements of the implant surface have led to shorter healing periods, which has affected the overall treatment time. Methods for computer-assisted implant planning and surgical guides have been developed to improve treatment planning. Several techniques are involved in the manufacturing of implant-supported single crowns, from the traditional plaster models, wax, casting and porcelain veneering to 3D scanning, computer aided design and manufacturing. It is important that all these treatment modalities are evaluated in a systematic and scientific way to ensure that the treatment given is the best one possible according to the individual conditions that exist.

The general aim of this project was to evaluate the treatment outcome between different treatment modalities for single dental implants. Study I aims to retrospectively evaluate implant survival. Patient reported outcome measures, marginal bone loss (MBL), clinical and esthetic outcomes following conventional single implant treatment. The aim of study II, a prospective randomized clinical study, was to compare the overall treatment outcome following immediate loading (IL) and delayed loading (DL) of single implants. In study III the aim was to in a vitro setting evaluate the deviation in final dental implant position after the use of surgical guides fabricated from two different desktop 3D printers using a digital workflow. For study IV the aim was to, in a non-randomized study, compare clinical and aesthetic outcomes between immediately loaded single implants placed with and without a fully guided-surgery procedure (DIL). In study I a total of 85 implants were examined after a mean follow-up time of 7.51 years. The 5-year implant survival rate was98.4% (95% CI: 96.3% - 100%), with a crown survival rate of91.8% (95% CI: 86.3%-97.3%). Overall mean MBL was -0.13 mm. Final and initial total Pink esthetic score (PES) were 9.61 and 11.49 (P<.001) Mean White esthetic score (WES) was 6.48 at final follow-up. Visual analog scale (VAS) score for soft tissue and implant-supported crown aesthetics were 73.5 and 82.1 (maximum score 100). A oral health impact profile-14 (OHIP-14) 14 score of 16.11 was observed at the final follow-up. Study II and IV found implant survival rates of 100%, 96% and 90.5 % for IL, DL and DIL, respectively, after 1-year. No statistically significant differences were found for MBL, PES, WES and OHIP-14after 1-year. Statistically significant lower papilla index scores were found for the IL. Overall statistically significant improvement inPES, WES and OHIP-14 were found over time. In the DIL group a moderate correlation between aesthetics and deviation in fixture position was found. For Study III a statistically significant difference between stereolithography and direct light processing (DLP) was found fordeviation at entry point (P = .023) and the vertical implant position(P = .009). Overall lower deviations were found for the guides from the DLP printer, with the exception of deviation in horizontal implant position.The results from these studies suggest that good clinical results can be achieved with different treatment modalities for single implants. Positive advantages with immediate loading and guided surgery is primarily seen in the early faces of the treatment procedure only. Care needs to be exerted with technically complicated treatment procedures as the effect on implant survival should not be underestimated. Further studies have to be performed to evaluate guided surgery and immediate loading to identify possible factors effecting survival.