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

Plain English Summary

Background and study aims
Complete mandibular edentulism is the condition where all of the lower teeth are missing. It is a difficult condition for patients because complete removable dental prostheses (dentures) are extremely difficult to wear, move during chewing, lack stability and cause pain/discomfort when eating. A possible solution to stabilize the complete prostheses is to place dental implants in the mandible (lower jaw). Dental implants are titanium fixtures that can be placed in the bone to support the prosthesis and stabilize it, preventing movement and discomfort when eating. In order to obtain better stability of the prosthesis over the implants, the implants can be splinted by means of a bar to support the prosthesis. Conventionally, making a bar to support the prosthesis is a procedure that involves different laboratory steps, with a longer treatment time and higher costs for the patients. As an alternative, and in order to reduce the laboratory steps and time for this treatment, different welding techniques have been proposed for creating the bar inside the mouth of the patients. These techniques can be highly successful. In this study, a new technique for the making a mandibular bar is tested, the ball welding bar. The ball welding bar consists of smooth prosthetic cylinders, interconnected by titanium bars which are adjustable in terms of distance from the ball terminals and inserted into the rotating rings of the cylinders. All the components are welded and self-posing.

Who can participate?
Patients with complete mandibular edentulism and problems related to their complete, removable conventional dentures (i.e. lack of stability, discomfort during eating and aesthetic embarrassment)

What does the study involve?
All participants are treated using the new ball welding bar technique and are followed for a 2-year period in order to assess the survival of the implants and the success of this technique.

What are the possible benefits and risks of participating?
The ball welding bar technique can simplify the creation of mandibular bars, reducing time and costs, with clear benefits for the patients. For the dentists, the main advantages of this method are that it makes it easy to centre the bars over the bone crest, allows for fine regulation, and makes it easy to solder the framework without distortions. Finally, the procedure is very rapid and can be managed by a single operator, both of which allow for reduced rehabilitation costs.

Where is the study run from?
1. Studio Dentistico Guida (Italy)
2. Studio Dentistico Dr. Bacchiocchi (Italy)

When is the study starting and how long is it expected to run for?
January 2010 to December 2015

Who is funding the study?
Studio Dentistico Dr Andrea Guida (Italy)

Who is the main contact?
Prof. Andrea Guida

Trial website

Contact information



Primary contact

Prof Andrea Guida


Contact details

via Sartena 9
Lido di Ostia (RM)
+39 (0)6 562 3973

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

The ball welding bar: a new solution for the immediate loading of screw-retained, mandibular fixed full arch prostheses



Study hypothesis

The purpose of this study was to present a new intraoral welding technique, and in particular a new method for the fabrication of a bar (the ball welding bar) that can be used to support screw-retained, mandibular fixed full arch prostheses.

Ethics approval

Fundacao Universitaria Vida Crista (FUNVIC) Institutional Board, 25/01/2010

Study design

Non-randomised study

Primary study design


Secondary study design

Non randomised study

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details to request a patient information sheet


Implant prosthodontics


In the period between January 2010 and December 2013, all patients with complete mandibular edentulism or irreparably compromised mandibular dentition, who were referred to two different private dental centres patients for restoration of the masticatory function with a fixed mandibular prosthesis supported by dental implants, were treated with the new ball welding bar technique. The patients were then followed for a 2-year period, in order to evaluate the survival of the implants and the success of this technique.

Intervention type



Drug names

Primary outcome measure

Implant survival, i.e. the clinical condition in which the implants are still in function in the patients' mouth, at the end of the 2-year follow-up period

Secondary outcome measures

Prosthetic success, i.e. the clinical condition in which no adverse events or complications (such as fractures/alterations of the resin superstructure and of the intraorally welded titanium framework) occur at the prosthesis level, assessed at the end of the 2-year follow-up period

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Complete mandibular edentulism, with functional and aesthetic problems related to the presence of a complete, removable conventional denture (i.e. lack of stability of the complete denture, discomfort during function and aesthetic embarrassment)
2. Irreparably compromised mandibular dentition, due to advanced periodontal disease or destructive/massive tooth decay, that made the residual dental elements unrestorable
3. Sufficient bone volume (bone height x width) to allow for the placement of implants of at least 8 mm in length and 3.0 mm in diameter
4. Will to restore the masticatory function with a fixed mandibular prosthesis supported by dental implants
5. Ability to understand and sign an informed consent form for implant treatment.

Participant type


Age group




Target number of participants


Participant exclusion criteria

1. General medical conditions/systemic diseases that represented an absolute contraindication to surgical and implant treatment, such as severely immunocompromised patients or severely uncompensated diabetics, patients receiving radiotherapy to the head and neck area or chemotherapy, patients receiving amino-bisphosphonates intravenously and/or orally
2. Psychiatric disorders
3. Addicted to alcohol or drugs
4. Needed bone augmentation procedures with autogenous bone or other bone substitutes, to allow for proper implant insertion
5. Previously undergone major regenerative bone surgery, preliminary to the placement of dental implants

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

Studio Dentistico Guida
via Sartena 9
Lido di Ostia (Roma)

Trial participating centre

Studio Dentistico Dr. Bacchiocchi
Via Gaetano Donizetti 2
Castelfidardo (AN)

Sponsor information


Studio Dentistico Dr Andrea Guida

Sponsor details

via Sartena 9
Lido di Ostia (RM)
+39 (0)6 562 3973

Sponsor type

Hospital/treatment centre



Funder type

Hospital/treatment centre

Funder name

Studio Dentistico Dr Andrea Guida

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Planned publication in a high-impact peer reviewed journal.

IPD sharing statement
The datasets generated during and/or analysed during the current study are/will be available upon request from Prof. Andrea Guida (

Intention to publish date


Participant level data

Available on request

Basic results (scientific)

Publication list

2017 results in:

Publication citations

Additional files

Editorial Notes

25/08/2017: Publication reference added.