Introduction: This study aimed to assess the effect of changes in tooth torque on the perceived color of composite and porcelain restorations.
Methods: A total of 30 patients with previous composite restorations and 30 patients with porcelain restorations on lateral and central incisors were selected. To simulate the effect of dental torque change, we asked the patients to tilt their heads upwards and downwards to represent buccal and palatal crown torque, respectively. Photographs were taken in 3 different positions (natural head position, 15° upward tilt, and 15° downward tilt). A laser alignment tool was used to help with head positioning. Color was measured on the 3 principal axes of the Commission Internationale de L'Eclairage, L∗, a∗, and b∗ color space using Photoshop software (Adobe, San Jose, Calif), and color differences were calculated. The midpoint of the clinical crown, both mesiodistally and incisogingival, was selected as the point of measurement. A general linear model was used to analyze the significance of changes in each value of different tooth torques. A t test was used to compare color changes of 2 different incisors (central and lateral) and overall color differences in the 2 types of restoration.
Results: Significant changes of the L∗ and a∗ values were found as a result of the change in head inclination, whereas b∗ values remained unchanged. It was found that buccal crown torque resulted in lighter and greener porcelain restorations. Composite restorations behaved similarly with the only difference being that the central incisors appeared bluer. Palatal crown torque resulted in a darker and redder porcelain restoration and a darker, redder, and yellower composite restoration. No significant differences were found between color changes in the central and lateral incisors. Furthermore, porcelain and composite restorations had similar color changes with alteration of head inclination.
Conclusions: Orthodontic changes of tooth torque alter the color perceived from composite and porcelain restorations.
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http://dx.doi.org/10.1016/j.ajodo.2020.08.013 | DOI Listing |
Med Sci Monit
January 2025
College of Dentistry, King Khalid University, Abha, Saudi Arabia.
BACKGROUND Indirect ceramic restorations often need multiple firings to match the shade of natural teeth or need after-correction and ceramic addition during the clinical trial stage. Many studies have examined how multiple firings affect the mechanical characteristics of zirconia-veneered prostheses. The effect of firing number on adhesion between these core and heat-pressed lithium disilicate veneering ceramics is unclear.
View Article and Find Full Text PDFBMC Oral Health
January 2025
Department of Orthodontics, Faculty of Dentistry, Biruni University, İstanbul, Turkey.
Objective: This study aims to examine color properties of repairs made with various composites on restorations produced through additive-manufactured resin composites (AM-RC) and zirconia (AM-Z) or subtractive manufacturing (SM) after coffee thermocycling (CTC).
Materials And Methods: Disk-shaped specimens (Ø10 × 2 mm; N = 120) were fabricated using six different material groups: additively manufactured resin composite (AM-RC) materials (Crowntec [C], NextDent [ND]), additively manufactured zirconia (AM-Z) materials (Lithoz [LI], INNI-Cera [IN]), and subtractively manufactured (SM) materials (CEREC Tessera [ALD], Vita Enamic [EN]). Subsequently, each group was further subdivided into two subgroups (n = 10) based on the type of repair using two different composites resins: Clearfil Majesty Posterior (CL) (n = 60) and Filtek Z350 (FZ) (n = 60).
BMC Oral Health
January 2025
Faculty of dentistry, Ain Shams University, Cairo, Egypt.
Objective: The purpose of this study was to evaluate the effect of different preparation depths (0, 2 and 4 mm) of different restoration designs (classic endocrown design versus overlay design) on marginal adaptation of restorations fabricated of two different restorative materials (lithium disilicate and PEEK).
Materials And Methods: Sixty mandibular natural molars were collected as abutments for the restorations of this study, and grouped in three main groups of different cavity depths (0, 2 and 4). Each group was divided into two subgroups according to material of fabrication to (L) for lithium disilicate (IPS emax CAD, Ivoclar vivadent, Switzarland) and (P) for PEEK (Bio-hpp, Bredent, Germany).
Beijing Da Xue Xue Bao Yi Xue Ban
February 2025
Department of Prosthodontics, Peking University School and Hospital of Stomatology & National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices & Beijing Key Laboratory of Digital Stomatology, Beijing 100081, China.
Adolescence is defined as a population ranging from ten to nineteen years old. Permanent teeth in adolescents are of critical significance as they are actively involved in mastication, contribute to aesthetic appearance, play a role in pronunciation, and are integral to the growth and development of the stomatognathic system. Specifically, permanent teeth in adolescents comprise those with incomplete root development and those with complete root development but unstable gingival margin positions.
View Article and Find Full Text PDFOral Health Prev Dent
January 2025
Purpose: This in-vitro study was conducted to assess the fracture resistance of resin-bonded ceramic endocrowns with different designs at varying intracoronal depths.
Materials And Methods: Forty-eight (n = 48) extracted mandibular first molar teeth were randomly divided into four groups (n = 12). In the control group, the specimens remained untreated.
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