Clinical and Patient Outcomes of 4 mm Ultra-Short vs. 8 mm Implants With Bone Augmentation in the Back Upper Jaw

Clinical- and Patient-related Outcomes of 4 mm Ultra-short Implants Compared to 8 Mm-long Implants With Bone Augmentation for the Rehabilitation of Posterior Atrophic Maxilla: a Randomized Controlled Clinical Trial.

This study aims to compare 2 different groups of patients with both a healed site in the upper posterior sector after extractions, one treated with ultra-short implants, and another with long implants with bone regeneration. The objective is to evaluate if short-implants are superior in terms of better clinical outcomes, survival rates and safety, reduced surgical time, postoperative discomfort, and complication risk compared to conventional implants and bone regeneration.

Study Overview

• Status: Not yet recruiting
• Conditions: Posterior Atrophic Maxilla
• Intervention / Treatment: Device: Ultra short implants; Device: Long implants with bone augmentation

• Study Type: Interventional
• Enrollment (Estimated): 35
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

inclusion criteria:

• Inform consent signed.
• Adult patients (≥18 years old).
• No pregnant women or without the desire to stay.
• Periodontal and peri-implant health in a pristine or reduced periodontium.
• Full mouth plaque score < 20% (O'Leary, 1972)
• Maxillary multiple posterior maxillary healed sites at least 4 months after extraction (with antagonist teeth with a good prognosis (Lindhe et al. 2008)) presenting ≥ 6.5 mm of bone width and 5-6 mm in height from the bone crest to the floor of the sinus.
• Need for a multiple splinted implant supported restoration with distal adjacent teeth or distal free-end in the posterior maxilla

exclusion criteria

• Patients with uncontrolled systemic diseases.
• Smoker patients (≥10 cig/day).
• Patients taking medications that affect bone metabolism or immunologic disorders.
• Patients allergic to penicillin.
• Patients presenting acute or chronic maxillary sinus lesions.
• Advanced vertical crestal bone atrophy in the posterior maxilla (Type V and IV, Cawood-Howell Classification)
• Vertical space of < 6 mm for a screw-retained implant restoration.
• Patients referring allergy to titanium or to any component of the implant/restoration.
• No previous attempts of implant installation in the same surgical site.
• Pregnant or lactating women.
• Patients willing to start or in course of an orthodontic therapy.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: ultra-short implants; 4mm long implants	Device: Ultra short implants; Placement of an ultra short implant of 4mm in the posterior atrophic maxilla without any bone regeneration procedure
Other: long implants with bone augmentation; 8mm long implants after transcrestal sinus floor elevation with bone augmentation	Device: Long implants with bone augmentation; Placement of long implants of 8mm in the posterior atrophic maxilla alongside bone augmentation

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Satisfaction of the surgical procedure	The patient is gonna make a subjective assessment of satisfaction of the surgery once it is finished. For that, we are going to use a 10 centimeter visual analog scale. The extremes of the scale are the extreme expressions of satisfaction, where the extreme left represents a 0 (not satisfied) and 10 (very satisfied). The patient won't have numbers between 0-10 so he will not be influenced by them. Wherever he marks, we will measure it and it will represent in centimeters how was his satisfaction	The day of the intervention after the surgery is finalized

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Surgical time	elapsed time since the administration of local anesthesia until the placement of the last suture knot, with a scale of the exact minutes	at the day of the intervention, since the administration of the anesthesia until the placement of the last suture knot
Pain Intensity	Subjective assessment of pain intensity using a 10-cm visual analog scale. The extremes of the scale are the extreme expressions of pain	Since the day of the intervention once the surgery is finalized , until the 7th day after the surgery, each day of the following 7 days
Rescue medication	The need to intake rescue medication of Ibuprofen 600mg, Paracetamol 650mg or Amoxicilin 500mg with a nominal response of Yes or No	After the surgery during the next 7 days
Intra-surgical complications	Any undesired event that happens during the surgical procedure, for example, profuse bleeding, Schneider membrane perforation, by a categorical nominal answer Yes or No	The day of the surgery
Post-surgical complications	Any undesired event that happens during the first week of healing	7 days after the surgery
Implant survival	If the implant is present in the mouth regardless of the biological or technical complications. An implant will be considered as failed if explantation is needed for the following reasons: (i) lateral, vertical mobility or rotation; (ii) drastic decrease in the ISQ values over time; (iii) discomfort or pain; and (iv) peri-implant radiolucency compatible with fibrointegration. It will be evaluated in a categorical nominal answer Yes or No	From 10 weeks after surgery to 36 months, after restoration delivery
Marginal bone level changes	distance from the mucosal margin to the base of the peri-implant pocket as measured with a PCP UNC 15 periodontal probe. By a mm scale	The day of the surgery, 12 months after and 36 months after
Probing pocket depth	distance from the mucosal margin to the base of the peri-implant pocket as measured with a PCP UNC 15 periodontal probe. Scale in mm.	12 months after surgery and 36 months after surgery
Bleeding on probing	: presence or absence of bleeding when performing the peri-implant probing. By a categorical nominal answer Yes or No	12 months and 36 months after surgery
Suppuration on probing	Presence or absence of suppuration when performing the peri- implant probing. By a categorical nominal answer Yes or No	12 months and 36 months after surgery
Keratinized mucosa width	distance from the mucogingival line to the peri-implant mucosal margin in the buccal site as measured with a PCP UNC 15 periodontal probe. In a mm scale	12 months and 36 months after surgery
Soft tissue dehiscence	exposure of any of the abutment or implant components, by a categorical nominal answer Yes or No	12 months and 36 months after surgery
Prosthetic complications	Any undesired event in the prosthetic component (abutment or crown), for example, screw loosening, ceramic chipping	12 months and 36 months after surgery

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Age	Elapsed time from the birthdate until the date of intervention assignment. Expressed in exact years.	The day of the inform consent and selection period and 7 days after the surgery
Gender	male/female. Expressed as absolute and relative frequency.	The day of the inform consent and selection period
Smoking habit	Non-smoker, Smoker ≤ 10 cig per day or Former smoker. Expressed as absolute and relative frequencies.	The day of inform consent and selection period
Bone density	Subjective evaluation during drilling. Type I, II, III, IV (Lekhom and Zarb, 1986). Expressed as absolute and relative frequencies.	The day of the surgery
Full mouth plaque score	Proposed by O'Leary in 1972. Expressed as relative frequency.	12 months and 36 months after surgery
Full mouth bleeding score	Proposed by Ainamo and Bay in 1975. Expressed as relative frequency.	12 months and 36 months after surgery
Crown to implant ratio	Relationship between the crown and the implant length. Measured in periapical radiographs. Expressed as mean and SD/median or IQR.	6 months after surgery
Implant position	1st or 2nd molar. Expressed as absolute and relative frequency.	The day of Informed consent
Primary & secondary implant stability	Based on a resonance frequency analysis (with ISQ values). Expressed as means and SD /median and IQR.	The day of the surgery and 10 weeks after surgery
Vertical soft tissue height	Measured with a PCP UNC 15 periodontal probe as the distance from the bone crest to the most coronal portion of keratinized tissue once the buccal flap is raised. Expressed as means and SD /median and IQR.	The day of the surgery

Collaborators and Investigators

• Sponsor: Universitat Internacional de Catalunya

Study record dates

Study Major Dates

• Study Start (Estimated): February 20, 2026
• Primary Completion (Estimated): July 1, 2028
• Study Completion (Estimated): July 1, 2029

Study Registration Dates

• First Submitted: January 14, 2026
• First Submitted That Met QC Criteria: February 10, 2026
• First Posted (Actual): February 18, 2026

Study Record Updates

• Last Update Posted (Actual): February 18, 2026
• Last Update Submitted That Met QC Criteria: February 10, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: PER-ECL-2024-07

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: No