Long-Term Periodontal Tissue Changes Associated With Metal-Ceramic Crowns: An 8-Year Split-Mouth Study

The goal of this clinical trial is to to evaluate the periodontal condition around metal-ceramic crown. The main question to be answered is: whether the metal-ceramic crown is the cause of gum changes? The study offers to involve patients who receive single metal-ceramic crown and have kept the same tooth intact on the other side of the mouth.

The condition of the gums around the crown will be compared with the corresponding natural teeth on the oposite side of the mouth. Clinical parameters such as plaque accumulation, bleeding on probing, periodontal pocket depth and gingival recession will be evaluated. All procedures are part of routine dental examination.

Participants:

will be invited for gingival examination 3 months after receiving the metal-ceramic crown, will receive a routine hygiene instruction, will be invited for gingival re-examination after 8 years.

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Key information

Conditions

Gingival Health Metal-Ceramic Restorations

Age range

20 year–75 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

About this study

The aim of this study is to evaluate the effects of metal-ceramic (MC) crowns on periodontal tissues over 8-year period, using a split-mouth design by comparing treated teeth with contralateral teeth within the same oral cavity.

The preparation and manufacturing of the MC crown is performed following a standardized clinical and laboratory protocol. Tooth preparation follow routine requirements, including creation of a chamfer preparation line and placing the crown margin equigingivally.

An initial follow-up examination is performed three months after the placement of the MC crown. The examination is performed by a prosthodontist under a dental operating light, using a flat-surfaced intra-oral mirror and a dental/periodontal probe. Both the restored tooth (test) and the contralateral natural tooth (control) are examined.

Attention is paid to examin the gingival tissue determining the degree of gum inflammation, the amount of plaque around the crown. The depth of the gum pockets are measured and the amount of recession is determined.

Inspection records are made twice, 3 months and 8 years after the placement of MC crowns.

All data are confidential and are used only within the framework of the study. Participation is voluntary. Patient have the option to withdraw their participation in the study at any time. This will not affect further treatment at institution.

If patients have any questions about the study they are invited to contact: call or visit the Clinic of Prosthetic Dentistry/ RSU Institute of Stomatology.

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

Patients with a tooth-based metal-ceramic crown intended.
Patients with a good general state of health, i.e. do not suffer from chronic uncontrolled general illnesses (diabetes, cardiovascular diseases, oncological diseases).
Patients who have corresponding natural tooth on opposite side without a fixed dental prosthesis (crown, bridge).

Exclusion criteria

Pregnancy.
With local inflammation and diseases of the oral mucosa.
With removable prostheses in both jaws.
Smokers (>20 cigarettes per day).
With an extraction wound next to an exposed tooth.
With neurological or psychiatric problems that affect hygiene.

Treatment and study plan

Metal-ceramic crown

Device

The preparation and manufacturing of the MC crown was performed following a standardized clinical and laboratory protocol. Final impression was taken with a one-step technique in a standard tray. All crowns were manufactured in the same dental laboratory. The metal frameworks were fabricated in cobalt-chromium using the lost-wax technique and then veneered with ceramic using a layering technique. All restorations were cemented with zinc phosphate cement.

The examination was performed under a dental operating light, using a flat-surfaced intra-oral mirror and a dental/periodontal probe. Both the restored tooth (test) and the contralateral natural tooth (control) were examined. Records were made for the gingival condition using the Silness & Loe gingival index. Gingival pocket depth measured in millimeters, gingival recession was measured as distance in millimeters (mm) from the cementoenamel junction to the gingival margin.

Other names: Gingival pocket depth, Gingival recession, Gingival index

Primary outcomes

Clinical parameters

Time frame: 8 years
Records were made for the gingival condition of test and control using the Silness & Loe gingival index, scoring four sites (M, D, B, L) for each tooth. The mean value for each tooth was then calculated.

Gingival index (GI) according to Silness & Loe. Scores Description 0-Normal gingiva,
- Mild inflammation: slight change in color, slight edema, no bleeding on probing,
- Moderate inflammation: redness, edema, and glazing, or bleeding on probing,
- Severe inflammation: marked redness and edema, tendency toward spontaneous bleeding.
Gingival pocket depth measured in millimeters was assessed at 6 surfaces per tooth by inserting a dental probe between teeth and gumline and recording the distance from the gingival margin to the base of the pocket, with the deepest measurement considered. Gingival recession was measured as distance in millimeters (mm) from the cementoenamel junction to the gingival margin, with the greatest value recorded.

Sponsors and collaborators

Lead sponsor

Riga Stradins University

Other

Registry information

Official study title

Long-Term Assessment of Periodontal Tissue Health Following Metal-Ceramic Crown Use: Complication Rates and Prevention Strategies

Important dates

Study start: 2015
Primary completion: 2016
Study completion: 2024
First posted: Mar 30, 2026
Registry last updated: Apr 3, 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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Completed