Musculoskeletal disorders are leading causes for long sickness absences and early retirement. Dental work is physically strenuous, and many studies have shown a relation between work-related MSDs and dentistry. However, fewer studies have focused on how these conditions affect the work ability of dentists. This study aimed to reveal the relationship between MSD, work ability and sickness absences in Finnish dentists and dental students. A questionnaire was sent to 1200 dental workers and students. It inquired of age, gender, use of dental loupes, physical exercise, use of health care, and site, length and frequency of musculoskeletal complaints. Work ability was assessed with four parameters: work ability score (WAS), future work ability (FWA), self-estimation of MSD-related work disability, and sickness absence days. The questionnaire gained 255 responses (response rate 21%). The majority (90%) of the respondents had experienced MSD during the past year but only eleven percent of them had been on sick leave. MSDs correlated significantly with WAS, FWA and MSD-related work disability. Results remained significant even age adjusted. Age was a strong predictor of declined work ability, but gender, physical exercise or dental loupe use did not have a significant impact. Despite all the ergonomic advances in modern dentistry, the occurrence of MSD symptoms is still high. MSDs seem to affect dentists' work ability significantly, but amount of sickness absence is relatively low, which may indicate a high level of presenteeism.