Is there evidence of a sphincter system in Wharton's duct? Etiological factors related to sialolith formation

Abstract

Abstract:The exact cause of the formation of sialoliths is unknown. Detailed knowledge of the pathogenesis of sialolithiasis is necessary to define new therapeutic procedures. The possible presence of a sphincter system in Wharton's duct has been described frequently in the context of diagnostic sialendoscopy. Serial histological examination of the entire Wharton's duct in four samples revealed no anatomical correlation for the presence of a sphincter. Secretory disturbances and viscous secretions as well as microlith formation and ductal obstruction cannot fully explain the genesis of sialoliths. The coaction of those factors with participation of bacteria leads to the development of sialoliths. (J. Oral Sci. 45, 233-235, 2003)

Sialolithiasis in equids, a report on 21 cases

“…This explanation would have to presuppose coincidental bilateral nidus formation of similar chronicity in these 2 cases. The possible presence of a sphincter system in the human parotid duct has been mooted as a possible cause of sialolithisis in man; however, serial histological examination has so far revealed no evidence of such a sphincter (Teymoortash et al 2003). More convincingly, research in human medicine has shown significant differences in composition of saliva between affected and control groups particularly in regard to salivary calcium, which was higher in the affected group, and salivary phytate concentration which was lower in the affected group.…”

On the Structural Diversity of Sialoliths

“…during the calculus formation~Takeda & Ishikawa, 1983;Harrison et al, 1997;Riesco et al, 1999!. Calcification may then be further assisted by factors such as saliva composition~Westhofen et al, 1984;Grases et al, 2003! andretention in the ductal system~Harrison et al, 1997;Teymoortash et al, 2002Teymoortash et al, , 2003 A "silent" growth period following the core formation stage is thought to generate the multilayered structure observed in most sialoliths. After this growth stage, the process eventually culminates at an inflammatory episode that determines the clinical symptoms and leads to the detection and surgical removal of the calculus~Faure et al, 1986!. Laminated structures of bright and dark layers have been reported by several authors and, in fact, seem to constitute the major organization type during growth~Faure et al., 1986;Riesco et al, 1999!. The alternating heavily calcified and organic layers are thought to result either from a rhythmic deposition of minerals similar to a Liesegang phenomenon~Anneroth et al, 1975, 1978! or from a simpler and slow sequential deposition of layers during the course of the silent growth period~Faure et al, 1986!.…”

An anatomical study of the buccinator muscle fibres that extend to the terminal portion of the parotid duct, and their functional roles in salivary secretion

“…(2001) suggested that the presence of a sphincter system in Wharton's duct was another possible risk factor for sialolithiasis. However, Teymoortash et al. (2003) reported that Wharton's duct had no anatomical correlation with the presence of a sphincter and did not support the involvement of sphincter‐like structures during the formation of sialoliths.…”