Gastric emptying rate in subjects with experimentally shortened dental arches: A pilot study

Although a shortened dental arch has been reported to provide sufficient subjective chewing ability, the loss of molar occlusion significantly reduces trituration ability, and may result in an impaired digestive function including delayed gastric emptying. This study investigated the effect of the experimental loss of molar occlusion on gastric emptying rate. Thirteen healthy dentate males underwent two sessions of gastric emptying rate measurement after ingestion of the same test meal that contained ham, bread and an egg mixed with carbon-labelled octanoic acid. A test food was divided into nine equal portions, and each was consumed in 60 cycles of chewing. In one of the two sessions, the subjects wore an intraoral appliance devised to simulate the occlusal conditions of the shortened dental arches. Two parameters of gastric emptying; namely, the lag phase (T_lag) and gastric half-emptying time (T_1/2), were evaluated by means of a ¹³C-octanoic acid breath test. Following the measurement of gastric emptying in each session, masticatory performance was evaluated by a conventional sieve test. Masticatory performance decreased significantly in case of loss of molar occlusion (78.1 ± 11.1% versus 33.4 ± 18.2%, P <0.001); however, no significant changes were observed in terms of the gastric emptying parameters (T_lag: 99 ± 19 versus 105 ± 34 min; T_1/2: 168 ± 32 versus 178 ± 48 min). Within the limitations of this study, it was concluded that reduction in food trituration caused by shortening of the dental arch does not significantly affect gastrointestinal digestive function.