Evaluating the Efficiency of Newly Designed Prefabricated PMMA Crowns for Restoring Primary Teeth in Comparison to Stainless Steel and Zirconia Crowns

The aim of the present study is to evaluate the PMMA crowns regarding the following aspects:

I. Clinical evaluation of PMMA crowns regarding wear of opposing teeth when compared to zirconia crowns and stainless steel crowns after 6 months, and 12 months.

II. Color stability of PMMA crowns and zirconia crowns after 6 months, and 12 months.

III. Gingival health of restored teeth after 6 months, and 12 months. IV. Patient's satisfaction regarding the appearance and clinical performance of PMMA crowns when compared to stainless steel crowns and zirconia crowns through a given questionnaire.

Inclusion criteria

• Children included in the study should conform to the following criteria:

• Aged 5-8 years old
• Medically free
• Patient should suffer from extensively decayed primary lower second molar that will undergo pulpotomy.
• The anticipated exfoliation date of the selected primary teeth has to be more than 12 months from the date of the study start.

Exclusion criteria

Children with the following criteria will be totally excluded from the study:

<!-- -->

• Children who are extremely uncooperative and difficult to manage.
• Children suffering from any medical conditions that can't be managed in the clinic.
• Teeth with decay extending beneath the free gingival margin.
• Teeth that were grossly broken down, that cannot be restored.
• Presence of uncontrolled bleeding.
• Clinical or radiographic evidence of non-vitality such as presence of an abscess or a sinus, obvious discoloration, and premature hypermobility.