Condition category
Oral Health
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting

Plain English Summary

Lay summary under review 3

Trial website

Contact information



Primary contact

Dr Sergio Motta


Contact details

Rua Barão de Flamengo 22
Sala 801 Flamengo
Rio de Janeiro

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

A randomised controlled trial comparing nitrogen balance after prosthetic rehabilitation of complete edentulous patients with fixed prosthesis or implant retained overdenture


Study hypothesis

Complete edentulous patients wearing conventional dentures generally show chewing difficulties due to ill-fitting dentures may profoundly influence one’s desire and ability to eat properly. It has been suggested that these factors can lead to an unbalanced diet and deficient nutrient intake. Studies have shown that the ability of edentulous patients to chew most foods improves significantly when the mandibular denture is fully or partly supported by endosseous implants. Complete denture wearers have been shown to have significant differences in nitrogen intake when compared to patients that received implant-supported overdenture.

The purpose of the current study was to clarify the objective impact of implant-supported overdentures on mastigatory performance, nutritional state and nutritional habits. The research questions evaluated were:
1. Whether implant supported overdentures provide greater improvement in mastigatory performance compared to conventional dentures
2. If implant supported overdentures impact food selection
3. Whether implant supported overdentures provide higher protein intake and improved protein utilization
Nitrogen Balance (NB) is an important calculation for assessing nutritional response and it is used to evaluate the adequacy of protein intake as well as to estimate current protein requirements.

The results showed that stability of the mandibular implant-retained overdenture was enhanced compared to a conventional denture as well as the quality of life and satisfaction levels. Seventy-five percent of patients changed their nutritional pattern, has been evidenced by the 24-hour dietary test. This change led to a substantial increase in protein intake and, as a consequence, to a improved nitrogen balance.

Ethics approval

The ethics approval was not sought because it is a verification of the efficiency of removable prosthesis implant. This is not an experimental study.

Study design

Randomized controlled trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting

GP practices

Trial type


Patient information sheet

Not available in web format, please contact or to request a patient ifnormation sheet




Subjects received either implant-supported denture (ISD) or tissue-implant-supported denture (TISD)

The 24-hour dietary recall method was selected to measure dietary intake of the patients in the current survey. This was based on a review of the literature, which has used the 24-H- RQ method. Twenty-four hour urine collection was performed in order to estimate protein metabolism by collecting a person's urine in a special container over a 24-hour period.

Evaluation of protein metabolism
There was no change in the treatment and diet of patients during the course of the study. On
the test day, in the morning at the commencement of collection period (6.00 a.m.) patients were asked to void urine and discard this sample (as it contains the overnight urine present in the bladder). Subsequently urine was collected for next 24 hrs. The last sample was to be collected on next day at 6.00 a.m. A random sample was also collected at around 11.0 a.m. on the day of deposition of 24 hr sample (the test day).

Nitrogen balance trial
Nitrogen excretion is determined by certain factors, mainly crude protein content of diet. Nitrogen balance trials are not only used to determine amino acid requirement, but also for the best amino acid ratio (Hahn and Baker, 1995). A nitrogen balance trial was carried out with 4 patients. The values of nitrogen intake (NI), output in feces (NOF) and in urine (NOU) were calculated by multiplying nitrogen levels of diets, feces and urine, by feed intake, excreted feces and urine, respectively. Nitrogen absorption (NAB = NI – NOF), total output (TNO = NOF + NOU), retention (NR = NI - TNO), net protein utilization (NPU = NR/NI) and the biologic value of feed protein (BVFP = NR/NAB) were subsequently calculated. The values of nitrogen intake (NI), output in feces (NOF) and in urine (NOU) and UUN are the nitrogen production during the 24-hour period.

Intervention type



Not Specified

Drug names

Primary outcome measures

Nitrogen Balance (NB) for assessing nutritional response and to evaluate the adequacy of protein intake as well as to estimate current protein requirements

Secondary outcome measures

1. Patient overall satisfaction: Was significantly higher for the mandibular overdenture. In addition, mandibular overdenture patients were significantly more satisfied with chewing experience and retention of the lower denture. conversion from a lower conventional complete denture to an implant-retained overdenture increased retention of the prosthesis
2. Improvement in masticatory performance
3. Protein ingestion: limited effect has been observed

Overall trial start date


Overall trial end date


Reason abandoned


Participant inclusion criteria

1. Subjetts aged 54-79
2. Subjects must be bimaxillary edentulous patients wearing conventional dentures and without deglutition problems
3. Informed written consent

Participant type


Age group




Target number of participants


Participant exclusion criteria

Sera of patients with compromised metabolic health with chronic diseases

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

Rua Barão de Flamengo 22
Rio de Janeiro

Sponsor information


Free Center of Dentistry (Brazil)

Sponsor details

Rio de Janeiro
Rua Barao do Flamengo
Room number 22801
Rio de Janeiro

Sponsor type

Hospital/treatment centre



Funder type

Hospital/treatment centre

Funder name

Free Center of Dentistry (Brazil)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Results - basic reporting

Publication summary

Publication citations

Additional files

Editorial Notes