Objective To compare the sociodemographic and clinical features of odontogenic infections between hospitalised and non-hospitalised adult patients.

Methods The two study groups consisted of inpatients (IP) and outpatients (OP) with odontogenic infections who were treated at Christchurch Hospital, New Zealand. Clinical and sociodemographic data were collected retrospectively from patients' hospital records.

Results The study sample consisted of 28 IP (13.9%) and 174 OP (86.1%). There were no significant differences in age, gender or ethnicity between the two groups. A higher proportion of IP had trismus (75.0% IP; 6.9% OP), floor of the mouth oedema (10.7% IP; 0.6% OP) and decreased tongue mobility (10.7% IP; 1.7% OP). The IP group also had a greater proportion of multiple-space infections (39.3%) than the OP group (18.9%). The most commonly involved anatomical space in the OP group was the buccal space (49.4%), while that in the IP group was the submandibular space (57.1%). The submandibular, submental and submasseteric spaces were more likely to be involved in the IP group (p<0.05). The most common source of odontogenic infections in the IP group was the mandibular third molars (20.8%) and first/second molars (20.8%), while that in the OP group was the mandibular first/second molars (30.9%).

Conclusions There are important differences in the features of odontogenic infections between hospitalised and non-hospitalised patients. Some of these clinical signs may assist in recognising severe courses of odontogenic infections that may potentially require hospitalisation.