Feeding by tube is commonly used for inpatients and ambulatory patients. For this purpose nasogastric (NG) intubation is the traditional approach. The aim of this study was to develop the orogastric (OG) intubation with dental fixation and compare OG versus NG intubation in healthy volunteers.

In this randomized, open label, clinical trial with crossing over design, 13 healthy individuals were invited to participate. The study was performed at Hospital São Vicente de Paulo between July and December 2017. Those who accepted were studied after signing an informed consent form. Sample estimation (software WinPEPI) indicated that 13 participants would be enough to show a difference between OGI and NGI of 1 hour in terms of tolerance (SD 30 min), with alpha 5% and power of 80%. Inclusion criteria were age between 18 and 70 years, absence of any acute or chronic disease and intact upper posterior molars or premolars. The study was conducted according to rules of the Helsinki declaration and was approved by the local Ethical Committee (number 1.942.505).

The participants were randomly allocated to OG and NG intubations with a 15 days interval. Randomization was carried out with computed generated aleatory numbers. A trained dentist (RS) performed OG intubation with dental fixation. After explanation about the procedure, the patient was placed in Fowler position (45º) and intraoral infiltrative anesthesia was carried out with Lidocaine 2% (without vasoconstrictor) at gingival papilla in the vestibular-palatine direction. A polyurethane enteral tube (Medicone®, Cachoeirinha - Brazil) was inserted through the mouth and passed into de stomach, followed by fixation of the tube tip to a superior molar or premolar, in its palatine surface. For dental amarry we used a suture wire in stainless steel size 1.0 (Johnson & Johnson - Ethicon, São Paulo, Brazil).

NG intubation followed the traditional steps described elsewhere and was executed by the first author (RS). Briefly, after nostril anesthesia with xylocaine gel, a polyurethane enteral tube was inserted through the nose and its tip was positioned in the gastric lumen, according to the nose-ear-xiphoid method. The tube was attached to the face using antiallergic adhesive tape.

During both OG and NG intubations the participants were monitored regarding the occurrence of nausea, vomit, cyanosis, dyspnea, cough and discomfort. A bottle containing 900 ml of enteral diet (1.5kcal/ml, Nutrison Energy - Danone®, São Paulo - Brazil) was provided for each participant, with instructions of use. They were explained how to manually remove the tube if necessary, and asked to return to the hospital in the following day.

The main efficacy outcome was tolerance in hours. After intubation patients were asked to return in 24 hours for tube removal, but were allowed to withdraw the tube at any time in case of substantial discomfort. Secondary outcomes were discomfort, handling, speech, mastication, deglutition and esthetic. These efficacy outcomes were assessed using a self-reporting questionnaire in which participants were asked to reply after tube removal. Each outcome was rated by means of a 10-item Likert scale (0 = best / 10 = worst). Safety outcomes were registered either by the researcher during the intubation procedure (placement and removal) or by the participants replying an open question: "please describe any complaint related with the intubation".

Inclusion Criteria:

• Age between 18 and 70 years;
• Healthy volunteers;
• Individuals to participate in the study who referred to becoming superior of the subsequent intact students (Molars or premolars, either side);
• Individuals of both sexes.

Exclusion Criteria:

• Gastroesophageal complaints;
• Limitation of mouth opening;
• Pathologies of airways;
• Individuals invited to the study who reported bilateral upper posterior tooth loss;
• Inability to respond to the questionnaire