Allergies/asthma and root resorption: a systematic review

Progress in Orthodontics

Table 5 Evaluation of the level of certainty of the evidence by the GRADE PRO tool

Certainty assessment							Impact	Certainty	Importance
№ of studies	Study design	Risk of bias	Inconsistency	Indirectness	Imprecision	Other considerations	Impact	Certainty	Importance
Predisposition of allergic patients to orthodontically induced root resorption
4	Observational studies	Serious ^a	Not serious	Not serious	Not serious	All plausible residual confounding would suggest spurious effect, while no effect was observed.	Of the 4 studies included, one has a high RoB [17] and one a moderate risk [16]. Studies have limitations in the identification and control of confounding factors. Three studies state that allergy is not a risk factor for root resorption [16, 17], while a study with a low RoB states that allergy is a risk factor for orthodontically induced root resorption [11]	⨁⨁◯◯ LOW	IMPORTANT
Predisposition of asthmatic patients to orthodontically induced root resorption
3	Observational studies	Serious ^b	Serious ^c	Not serious	Not serious	Strong association. All plausible residual confounding would suggest spurious effect, while no effect was observed	Among the 3 studies evaluated, one has a moderate RoB [16] and the others have a low RoB [11, 15]. In addition to the lack of control of confounding variables, there is inconsistency between the results demonstrated by the value of the methodological heterogeneity between the studies. All studies conclude that asthma is not a risk factor for root resorption.	⨁⨁◯◯ LOW	IMPORTANT

^aOne study has high RoB [17], one has moderate [16], while the others have low [11, 19]. All studies are deficient in the identification and control of confounding factors
^bTwo studies have low RoB [11, 15], while one study has moderate RoB [16]. All are deficient in the identification and control of confounding factors
^cThere is considerable methodological heterogeneity between the studies, concerning the teeth evaluated for root resorption, the sample unit, and the methods of diagnosis of resorption