Objetive: The main objective of this clinical trial is to assess whether the oval section abutment of a 2.9mm implant achieves a greater covering of the tooth-implant papilla compared to a circular section abutment in 3.3mm implants in upper lateral incisors and lower central / lateral incisors.

Material and methods: fourty patients received unitary implants of 3.3mm or 2.9 mm diameter to replace the absence of upper lateral incisor or lower central/lateral incisor with an edentulous space of at least 6.4mm (mesio-distally). Esthetic and clinical parameters were evaluated 12 months after installation of the prosthesis.

Condition or disease: dental implants

Intervention/treatment: 3.3 or 2.9 mm diameter dental implants

Phase: Not Applicable

The study was a double-blind controlled clinical trial (RCT) comparing the oval section abutment of a 2.9mm (test group) to a circular section abutment in 3.3mm (control group) implants for the replacement of a single tooth.

The choice of the diameter to be used as recommended by the manufacter, was determined by the mesiodistal width between the two adjacent natural teeth, in order to maintain at least 1.5mm between the implant and the adjacent tooth. When said the distance was between 5.9 and 6.3 mm, a 2.9 mm implant was placed, while if the width ranged between 6.4 and 7.1 mm, a 3.3 mm implant was placed. Both implant designs are made of a titanium and zirconium alloy (Roxolid®) with a SLActive® surface (Institut Straumann AG, Basel, Switzerland).

The main objective was the papillary index (PI) (Jemt, 1997). It consists in four scores: 0 = absence of interdental papilla; 1 = filling of the interdental space less than 50% of the soft tissues; 2 = filling of the interdental space greater than 50% of the soft tissues; 3 = total filling of the interdental space with good aesthetic harmony; 4 = Hyperplasic interdental papilla formation with irregular soft tissue. Both mesial and distal papilla will be recorded.

The secondary objectives are (a) to observe the stability of the soft and hard tissues after one year in function, (b) to assess the success and survival rate of the implants, (c) to assess the stability of the implants and their evolution and (d) to analyze the degree of patient satisfaction with the aesthetic result.

Inclusion Criteria:

• Patients >18 years of age
• Absence of upper lateral incisors or lower central / lateral incisors with an edentulous space of at least 6.4mm (mesio-distally).
• The teeth adjacent to the edentulous space must be natural.
• Patients who are in periodontal health.
• Signing of informed consent before entering the study.

Exclusion Criteria:

• Patients with any systemic condition or disease that may interfere with oral surgery.
• History of radiotherapy.
• Patients smoking more than 20 cigarettes per day.
• Pregnant or breastfeeding patients.

The data collected for the study will be identified by a code and only the researcher will be able to relate them. The personal data will be treated with absolute confidentiality in accordance with the Data Protection Law and will remain in the patient's clinical history. The coded data will only be used for the purposes of this project.

The clinical monitor will hide the treatment to the clinical observer, the patient and the statistician.