Overall the balance of research supports a link between increased frequency of consumption of sugars and incidence of dental decay, but not for total amount of sugars consumed.

Key research 

van Loveren C. (2019). Sugar restriction for caries prevention: amount and frequency. Which is more important? Caries Res, 53(2):168-175.
The results suggest that when fluoride is appropriately used, the relation between sugar consumption and caries is very low or absent. The high correlation between amount and frequency hampers the decision related to which of both is of more importance, but frequency (and stickiness) fits better in our understanding of the caries process. Reducing the amount without reducing the frequency does not seem to be an effective caries preventive approach in contrast to the reciprocity. 

Anderson CA, Curzon MEJ, Van Loveren C, et al. (2009). Sucrose and dental caries: a review of the evidence. Obes Rev, 10 Suppl 1:41-54.
In this review, 6 papers found a positive, significant relationship between sugar quantity and dental caries, 19 of 31 studies reported a significant relationship between sugar intake frequency and dental caries. The balance of studies does not demonstrate a relationship between sugar quantity, but a moderately significant relationship of sugar frequency to dental caries.

Other research

Skafida V & Chambers S. (2018). Positive association between sugar consumption and dental decay prevalence independent of oral hygiene in pre-school children: a longitudinal prospective study. J Public Health (Oxf), 40(3):e275-e283.
Children who snacked all day (rather than eating meals), consumed soft drinks more frequently, or ate sweets or chocolates once a day or more, had a higher chance of dental decay.  There was also an association between decreasing brushing frequency at age 2 and decay at age 5. For children eating sweets or chocolate once a day or more, brushing teeth more often reduced the chance of decay.

Barrington G, Khan S, Kent K, et al. (2019).  Obesity, dietary sugar and dental caries in Australian adults. Int Dental J, 69(5):383-391.
There was a positive association between dental caries experience and being overweight or obese compared with having normal weight or being underweight, as well as between sugar consumption with all four dental caries outcome measures.

Moynihan PJ & Kelly SAM. (2014). Effect on caries of restricting sugars intake; systematic review to inform WHO Guidelines. J Dent Res, 93(1), 8-18.
Of the studies, 42 out of 50 of those in children and 5 out of 5 in adults reported at least one positive association between sugars and caries. There is evidence of moderate quality showing that caries is lower when free-sugars intake is < 10% energy. With the < 5% energy cut-off, a significant relationship was observed, but the evidence was judged to be of very low quality.

Sheiham A & James WPT. (2014). A new understanding of the relationship between sugars, dental caries and fluoride use: implications for limits on sugars consumption. Public Health Nutr, 17(10):2176–2184.
Caries occurred in both resistant and susceptible teeth of children when sugar intakes were only 2–3% of energy intake, provided that the teeth had been exposed to sugars for >3 years. Despite increased enamel resistance after tooth eruption, there was a progressive linear increase in caries throughout life, explaining the higher rates of caries in adults than in children. Fluoride affects progression of caries development but there still is a pandemic prevalence of caries in populations worldwide.

Bernabe E, Vehkalahti MM, Sheiham A, et al. (2016). The shape of the dose-response relationship between sugars and caries in adults. J Dent Res, 95(2): 167-172.
The findings of this longitudinal study among Finnish adults suggest a linear dose-response relationship between sugars and caries, with amount of intake being more important than frequency of ingestion. Also, daily use of fluoride toothpaste reduced but did not eliminate the association between amount of sugars intake and dental caries.

Hong J, Whelton HL, Douglas GVA & Kang J. (2018). Consumption frequency of added sugars and UK children's dental caries. Community Dent Oral Epidemiol, 46:457-464.
Children who consume foods and drinks with added sugar more frequently are more likely to develop dental caries, but higher consumption frequency of drinking water in fluoridated areas might reduce dental caries.

Liska D, Kelley M & Mah E. (2019). 100% fruit juice and dental health: a systematic review of the literature. Front Public Health,7:190.
Prospective cohort studies in children and adolescents found no association between 100% fruit juice intake and tooth erosion or dental caries, but, RCT data in adults suggests that 100% fruit juice could contribute to tooth erosion and dental caries.