Effect of Face Mask Therapy on Blood Oxygen Levels

Skeletal Class III malocclusions are characterized by maxillary retrusion, mandibular protrusion, or a combination of both. In growing individuals presenting with maxillary deficiency, the face mask appliance is widely recognized as one of the most effective and frequently utilized orthopedic interventions. The primary objective of face mask therapy is to stimulate forward and downward growth of the maxilla by disarticulating and activating the circummaxillary sutural system. The application of protraction forces via a face mask results in anterior displacement of the maxillary dentition, accompanied by lingual inclination of the mandibular incisors. Orthopedic effects of the appliance typically include forward and downward movement of the maxilla with a slight degree of upward rotation, posterior dental extrusion, and backward rotation of the mandible. Numerous studies have demonstrated that combining rapid maxillary expansion (RME) with face mask therapy enhances skeletal outcomes, especially when initiated during the early stages of growth. Delayed intervention is often associated with reduced orthopedic responsiveness.

Foersch et al. evaluated the effects of pre-treatment rapid maxillary expansion on face mask therapy outcomes and concluded that expansion positively influences sagittal skeletal changes. In the absence of expansion, greater dental compensation was observed, particularly in the transverse dimension. From a clinical standpoint, anterior crossbite correction can typically be achieved within approximately 3 to 4 months, depending on the severity of the malocclusion. However, establishing a stable overbite and molar relationship usually requires an additional 4 to 6 months of treatment. A prospective clinical study analyzing treatment outcomes in Class III patients reported that overjet correction occurred through 31% maxillary advancement, 21% mandibular retraction, 28% labial proclination of the maxillary incisors, and 20% lingual retroclination of the mandibular incisors. To compensate for potential adverse effects of late mandibular growth, overcorrection of the overjet and molar relationship has been recommended. RME has also been associated with significant anatomical and functional changes in the upper airway. Specifically, an increase in the width of the nasal cavity base leads to a reduction in nasal airway resistance and improvement in nasal respiration. Recent investigations have documented post-treatment increases in pharyngeal airway dimensions and corresponding enhancements in nasal breathing. In a clinical study involving 25 patients with Class III malocclusion due to maxillary deficiency, face mask therapy resulted in a significant increase in nasopharyngeal airway space, which remained stable after a four-year follow-up period. Another study comparing 18 patients treated with RME and face mask therapy against an untreated control group of 163 individuals demonstrated a statistically significant enlargement of the nasopharyngeal space in the treated group. Pulse oximetry operates based on two fundamental physical principles. First, arterial blood generates a pulsatile signal, while non-pulsatile signals originate from venous and capillary beds. Second, modern oximeters utilize light-emitting diodes (LEDs) emitting at wavelengths of 660 nm (red) and 940 nm (infrared), as oxyhemoglobin and deoxygenated hemoglobin display distinct absorption spectra at these wavelengths. In a study conducted by Niaki et al., among patients exhibiting mouth breathing patterns, 65.4% were classified as hypoxemic, while 34.6% had normal oxygen saturation levels. Gender analysis revealed that 31.4% of males and 40% of females demonstrated normal oxygen saturation.Mouth breathing has been shown to influence craniofacial growth and may contribute to the development of various malocclusion patterns. Conversely, specific malocclusion types can exacerbate oral breathing tendencies. It is important to acknowledge that oral respiration has a measurable impact on blood oxygen levels and overall respiratory function.