An observational study in Implant-supported Single Crowns, Osseointegration and Peri-Implant Health, sponsored by Pontificia Universidade Católica do Rio Grande do Sul. Active, not recruiting at 1 site in Brazil. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-30.
Sponsored by Pontificia Universidade Católica do Rio Grande do Sul · Observational
The objective of this prospective cohort study is to evaluate marginal bone loss and peri-implant health in patients with single dental implants requiring prosthetic rehabilitation, comparing conventional and digital methods for fabricating implant-supported crowns over a 24-month period.
The primary questions the study aims to answer are:
Are there differences in marginal bone loss between implant-supported crown rehabilitations fabricated using conventional versus digital workflows?
Are the prosthetic fabrication methodology, crown design, and abutment characteristics associated with differences in peri-implant health and outcomes related to osseointegration?
How do peri-implant clinical parameters and marginal bone loss relate to the patients' oral health-related quality of life?
The researchers will follow two groups of patients: one undergoing prosthetic rehabilitation via conventional impression-taking, and the other via digital scanning. The projected sample size is 32 patients, with 16 in each group.
Dental implants are widely used in oral rehabilitation; however, their long-term success depends on the stability of the implant-prosthesis system and the maintenance of the health of the surrounding tissues. Biological complications, such as peri-implant mucositis and peri-implantitis, can compromise both soft tissues and the supporting bone. In addition to biofilm accumulation, factors related to the prosthetic configuration, the fit of the components, and the emergence profile of the crowns can influence local conditions and the feasibility of oral hygiene maintenance.
The development of digital technologies-including intraoral scanning and computer-aided design and computer-aided manufacturing (CAD/CAM) systems-has expanded the possibilities for planning and fabricating implant-supported restorations. Nevertheless, it remains to be clarified whether these technologies are associated with superior clinical and biological outcomes compared to conventional methods.
Study Design and Population
This study employs a prospective cohort design and will be conducted at the School of Dentistry of the Pontifical Catholic University of Rio Grande do Sul (PUCRS) in Porto Alegre, Brazil.
The projected sample will consist of 32 patients who already have single dental implants in place and require implant-supported restorations. Eligible patients who agree to participate will be enrolled upon signing an Informed Consent Form.
Participants will be monitored across two groups, defined according to the method used to fabricate the prosthetic rehabilitation:
Conventional Group: Prosthetic rehabilitation planned and executed via conventional impression techniques, utilizing impression copings, addition-cured silicone, dental stone casts, and standard prosthetic fabrication procedures.
Digital Group: Prosthetic rehabilitation planned and executed via intraoral scanning and digital data processing for the fabrication of the implant-supported restoration. Sixteen patients will be included in each group. To standardize the fabrication of the restorations, the study design specifies the use of the same dental laboratory and the same operator for the creation of the crowns.
Assessments and procedures
Participants will undergo a medical history interview (anamnesis), collection of sociodemographic data, clinical assessment of remaining teeth and implants, a peri-implant examination (periogram), photographic documentation of the crowns, and an evaluation of oral health-related quality of life using the Oral Health Impact Profile (OHIP-14) questionnaire.
Clinical assessments will be conducted at five time points: at the time of definitive crown placement (T0) and at 6 months (T1), 12 months (T2), 18 months (T3), and 24 months (T4) post-placement. Examinations will be performed by trained and calibrated examiners, following the procedures outlined in the protocol.
Peri-implant clinical parameters will include:
Bleeding on probing and the presence or absence of suppuration.
Modified plaque index.
Probing depth and marginal recession.
Height of the keratinized mucosa and gingival thickness.
Sulcular bleeding index and gingival phenotype.
Mucosal emergence angle and characteristics of the prosthetic emergence profile.
Radiographic assessment will be used to measure the marginal bone level around the implants. Digital periapical radiographs will be taken using the paralleling technique with customized positioning devices; measurements will be performed using image-processing software, based on anatomical landmarks of the implant and the bone-implant interface.
Data regarding the characteristics of the implants and restorations will also be recorded, including location, implant dimensions, platform and connection type, angulation of the prosthetic component, type of retention, presence of prosthetic misfit, timing of loading, material and characteristics of the abutments, and the method used for transferring the implant position.
Statistical analysis will be performed comparing the groups.
Pontificia Universidade Católica do Rio Grande do Sul is the lead sponsor of 23 studies on the registry; 4 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Patients treated at the undergraduate and postgraduate clinics of the Faculty of Dentistry, School of Health and Life Sciences, at the Pontifical Catholic University of Rio Grande do Sul.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Group in which implant-supported crowns were rehabilitated using a conventional workflow.
Group in which implant-supported crowns were rehabilitated using a digital workflow.
Peri-implant bone loss
Peri-implant bone loss measured by digital periapical X-rays. Comparing the bone level around the implants at pre-specified time points.
Time frame: From the enrollment to the end of the study - 0 days to 24 months.
Peri-implant health
Investigation of peri-implant health around the rehabilitated implants comparing: Bleeding on probing and the presence or absence of suppuration. Modified plaque index. Probing depth and marginal recession. Height of the keratinized mucosa and gingival thickness. Sulcular bleeding index and gingival phenotype.
Time frame: From the enrollment to the end of the study - 0 days to 24 months.
Patient satisfaction
Investigation of patient satisfaction using patient-reported outcomes (PROMs) - OHIP-49 (Oral Health Impact Profile) questionnaire. A score from 0 to 4 is assigned to each question. 0 is the best outcome, and 4 is the worst outcome.
Time frame: From the enrollment to the end of the study - 0 days to 24 months.
Ran from Jul 2024 to primary completion in May 2025, 10 months.
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From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is active, not recruiting, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.
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Pontificia Universidade Católica do Rio Grande do Sul