A Retrospective Study on Long-Term Technical Complications of Single Metal-Ceramic Crowns With a Supplementary Questionnaire Survey

This observational study aims to evaluate the long-term clinical outcomes and biological complications associated with metal-ceramic crowns. Patient dental records will be reviewed to identify eligible participants, who will subsequently be invited for a clinical examination. The clinical condition of the metal-ceramic crowns and the supporting teeth and periodontal tissues will be assessed using predefined clinical criteria. The study aims to provide information on the long-term clinical performance of metal-ceramic crowns and the occurrence of associated biological complications. Participants will also compleate a questionaire assessing oral health-related habits and satisfaction with metal ceramic crown.

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Key information

Conditions

Metal Ceramic Restorations Gingival Health

Age range

20 year–80 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Rīga Stradiņš University Institute of Stomatology

Riga, LV 1007, Latvia

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

adult patients with at least one metal-ceramic single crown meeting the predefined study criteria.
ability and willingness to participate in the clinical examination and complete the questionnaire

Exclusion criteria

teeth serving as abutments for fixed partial prostheses (FPPs)
teeth as abutments for removable partial dentures (RPDs)

Treatment and study plan

Metal-Ceramic dental single crown

Device

Metal - ceramic single crowns previously placed as part of routine dental treatment. No crowns are placed as part of this observational study. The existing restorations and supporting tissues are evaluated during clinical examination. The questionnaire was completed in paper format prior to the clinical examination and in the presence of the clinician. Responses were coded numerically for descriptive purposes, and mean satisfaction scores with standard deviations are reported.

Primary outcomes

Technical complications of metal-ceramic single crown

Time frame: Clinical examination in 2026

The assessed clinical parameters, based on the modified USPHS criteria, included veneer chipping, wear of the occlusal surface, anatomical form/contour, marginal adaptation, color match, and secondary caries (see Table 1), with the worst recorded score being documented.

Secondary outcomes

Biological complications of metal-ceramic single crowns

Time frame: Clinical examination in 2026

Gingival health was evaluated using the Silness and Löe Gingival Index (GI). The mesial, distal, buccal, and lingual sites of each tooth were scored, and the mean GI value was calculated for each tooth.

Gingival pocket depth was measured in millimeters at six sites around each tooth using a periodontal probe. The distance from the gingival margin to the base of the pocket was recorded, and the deepest measurement was used for analysis. To assess gingival recession (GR), the distance from the cementoenamel junction (CEJ) to the gingival margin was recorded in millimeters with the greatest value considered for each tooth.
Questionnaire on hygiene habits and satisfaction

Time frame: Prior clinical examination in 2026

Modified questionnaire in Latvian organizing the information into the following sections: oral hygiene habits (4 questions), disadvantages/ encumbrances with the crown (3 questions) and satisfaction (1 question) (Table 3) using Likert-style scale. Patient satisfaction was assessed on a 6 point ordinal scale (0 = completely dissatisfied to 5 = completely satisfied). Responses were coded numerically for descriptive purposes.

Sponsors and collaborators

Lead sponsor

Riga Stradins University

Other

Registry information

Official study title

A Retrospective Study on Long-Term Technical Complications of Metal-Ceramic Crowns With a Supplementary Questionnaire Survey

Important dates

Study start: 2026
Primary completion: 2026
Study completion: 2026
First posted: Sep 18, 2026
Registry last updated: Sep 18, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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