This study assesses the upper respiratory tract width at the

level of the adenoid in patients with a normal (nasal) and

abnormal (oral or mixed) breathing route. Aim. To compare

the upper respiratory tract width in the study group

(abnormal breathing route) and control group (normal

breathing route) and to determine the cut-off point and

mean limit values in order to conduct a differential diagnosis

between a habitual and constitutional breathing route.

Material and methods. The study included 221 patients

treated at the Aquadent-Ortoestetyka Clinic in Kielce. Based

on the medical history taken, clinical examination and

subjective evaluation of the upper respiratory tract width

according to Holmberg 112 patients were enrolled into the

study group and 109 patients into the control group. The

upper respiratory tract width was measured with two

different linear methods: a modified method by Holmberg and Linder-Aronson, and the Linder-Aronson and Henricson

method (AD1-PNS, AD2-PNS). Results. In the study group

the mean value of the Holmberg measurement is 4.25 mm,

and in the control group – 14.1 mm. Mean values of AD1-

PNS and AD2-PNS measurements in the study group are 8.1

mm and 9.5 mm, respectively, and they can be regarded as

mean limit values. The 6 mm Holmberg measurement is the

cut-off value between the study and control groups, and it

should be monitored. In relation to the Holmberg

measurement a difference between the study and control

groups is 9.85 mm. Regarding AD1-PNS and AD2-PNS

measurements a difference between the study and control

groups is 11.4 mm and 10.0 mm, respectively. Conclusions.

The upper respiratory tract width at the level of the adenoid

shows a statistically significant difference between the study

and control groups. It may indicate significant narrowing of

the upper respiratory tract at the level of the adenoid in the

study group or a different type of morphology of the facial

skeleton. Limit values obtained in the study allow

differentiation of a habitual and constitutional breathing

route. (Duda A, Stós W. Comparison of the upper

respiratory tract width at the level of the adenoid in

patients with normal and abnormal breathing route.

Orthod Forum 2018; 14: 106-18).