Table 5.

Main characteristics of the studies selected for the systematic review and meta-analysis with oral health as exposure 2019

author	Drug used by participants	Sample size	year	country	design	Quality of the evidence
Morio et al. [27]	Methamphetamine users	18	2008	USA	Case-control	High
Shetty et al. [54]	Methamphetamine users	571	2016	USA	Case-control	High
Rommel et al. [55]	Methamphetamine users	200	2016	Germany	Case-control	High
Thomson et al. [53].	Cannabis users	1015	2008	New Zealand	Cohort	High
Nives Protrka et al. [24]	Heroin users	200	2013	Croatia	Case-control	Moderate
Rooban et al. [48]	Heroin and Cannabis users	100	2008	India	Cross-section	Moderate
Reece [49]	Opiate users	233	2007	Australia	Cross-section	High
Kayal et al. [50]	Amphetamines	57	2014	Saudi Arabia	Cross-section	Moderate
D’Amore et al. [51]	Opioid and Marijuana users	563	2011	USA	Cross-section	High
Gupta et al. [52]	illicit drug users	126	2012	India	Cross-section	Moderate