PubMed-ID: 34694076Seiten: 494-513, Sprache: Englisch
When implementing a direct composite resin (CR) restoration, the determination of color can be a challenging step. The reproduction of tooth shade is often a source of frustration for the practitioner. Dental color can be complex, and its accurate reproduction requires not only a good understanding of color by the practitioner but also the use of appropriate methods to achieve it. It is important to remember what tooth color parameters one is able to mimic with CRs. The purpose of this article is to demystify the errors attributable to standard tools, ie, shade guides, and above all to suggest a number of measures to avoid such errors.
PubMed-ID: 34694077Seiten: 514-532, Sprache: Englisch
The present article describes a treatment planning clinical strategy based on a flowchart developed to facilitate the treatment of teeth with severely compromised clinical crowns. The study comprised a group of 978 patients presenting with 2327 teeth needing clinical crown reconstruction. The patients were screened, diagnosed, and treated with a multidisciplinary approach according to a flowchart structure. A subgroup of 75 teeth in 62 patients was considered irrational to treat when a composite risk-evaluation model was applied. Another subgroup of 168 teeth in 126 patients required periodontal surgery and received a minimally invasive crown lengthening (MICL) procedure. Endodontic treatment was necessary for 73 teeth, and retreatment for 51. Most of the teeth (124 in 94 patients) received a full crown, while the remaining 44 teeth received a direct (24 teeth) or an indirect (20 teeth) reconstruction. Six teeth were orthodontically extruded before surgery. The 1-year average probing depth and clinical attachment level at the treated teeth was 2.5 ± 0.5 mm and 2.7 ± 0.6 mm, respectively. Bleeding on probing was detected in 19 sites (11.3%). No side effects or short-term recurrences were detected in 168 treated sites. Patients described function and esthetics as extremely satisfactory, very satisfactory, or satisfactory. In conclusion, an accurate screening based on a flowchart supported the clinical decision to treat 168 teeth with MICL and to replace 75 out of 2327 teeth presented at our clinic for restorations. The use of MICL and the high-quality restorations resulted in a healthy periodontal and dental condition of all the treated teeth as well as patient satisfaction at the 1-year follow-up.
PubMed-ID: 34694078Seiten: 534-552, Sprache: Englisch
Purpose: The present study aimed to investigate the resistance and failure mode of broken-down endodontically treated incisors without ferrule restored with CAD/CAM endocrowns.
Materials and methods: Endodontically treated bovine incisors (N = 30) without ferrule were divided into two groups and restored with two types of CAD/CAM endocrowns: lithium disilicate (Eld) or resin nanoceramics (Erc). The preparations included a 4-mm–deep ‘internal ferrule’ and immediate dentin sealing. The samples were subjected to accelerated fatigue testing. Cyclic isometric loading was applied to the incisal edge at a 30-degree angle at a frequency of 5 Hz, beginning with a load of 100 N (5,000 cycles). A 100 N load increase was applied every 15,000 cycles. Specimens were loaded until failure or to a maximum of 140,000 cycles. Previously published data from the same authors regarding lithium disilicate crowns over post-and-core buildups without ferrule (NfPf), core buildups without post without ferrule (NfNpFR), and with a 2-mm ferrule (FNp) using the same experimental setup were included for comparison. Groups were compared using the Kaplan Meier survival analysis for cycles (log rank pairwise post hoc test comparisons at P = 0.05) and Life Table survival analysis for load at failure, followed by the Wilcoxon pairwise comparison at P = 0.05.
Results: All specimens failed before 140,000 load cycles. There was no statistically significant difference between the endocrown materials (Eld: 53,448 mean endured cycles; Erc: 52,397 mean endured cycles; P = 0.844). Endocrowns outperformed the group with lithium disilicate crowns on incisors without ferrule and post-and-core buildup (NfPf with mean endured 35,025 cycles), showed no statistical difference compared with the group with no-post fiber-reinforced composite resin core buildup (NfNpFR with 45,557 mean endured cycles), and had a lower survival rate compared with the group with ferrule (FNp with mean endured 73,244 cycles). Endocrowns generated a majority of non-catastrophic failures (with an advantage for Erc), while 100% of catastrophic failures were found in the group with a post.
Conclusions: CAD/CAM endocrowns of nonvital incisors without ferrule improved the resistance and optimized the failure mode when compared with traditional bonded crowns with adhesive post-and-core and no-post buildups.
PubMed-ID: 34694079Seiten: 554-569, Sprache: Englisch
The partial anterior ceramic restoration is a predictable and durable treatment modality that reestablishes not only esthetics but also strength and function. Bio-emulation, minimally invasive dentistry, and adhesive technology are key to a successful restoration. Partial restorations are only indicated when teeth have enough hard tissue on which to bond veneers. When there is more than 50% of dentin exposure, many clinicians still rely on macromechanical retention by performing a full-crown preparation. However, new research has shown good survival rates for partial restorations with extensive dentin exposure. The present article describes two cases in which a step-by-step protocol was applied to bond a laminate veneer to a tooth with dentin exposure.
PubMed-ID: 34694080Seiten: 570-578, Sprache: Englisch
Background: The palatal surface of the maxillary anterior teeth in conjunction with the incisal edge represents the mechanical area, which is of great importance for lateral and anterior guidance. Therefore, in terms of restorative dentistry, it is crucial for the clinician to have a detailed knowledge of the palatal surface anatomy (PSA) of the different maxillary anterior teeth in order to reestablish a definitive correlation between form, function, and esthetics. The aim of the present study was to analyze the variations in the PSA of the maxillary central incisors (CIs) and their correlation with tooth form and gender.
Materials and methods: Impressions of the maxillary arch of 500 study participants were taken and then classified according to PSA and tooth form. Statistical analysis was performed using Statistical Package for Social Sciences (SPSS) software. The chi-square test was utilized for comparisons among PSA, tooth form, and gender of the participants.
Results: The results showed Type 5 to be the most common PSA in maxillary CIs and the square tooth form to be the most common tooth form among both genders; Type 5 was also found to be the most common PSA within the square tooth form.
PubMed-ID: 34694081Seiten: 580-592, Sprache: Englisch
Background: The characteristics of the periodontium in anterior teeth influence the outcomes and prognosis of different periodontal, implant, and restorative procedures. In the present study, CBCT images were used to determine alveolar bone thickness and, to a lesser extent, gingival thickness. The aim was to evaluate the use of CBCT to measure the dentogingival complex in the anterior maxilla.
Materials and methods: CBCT scans from 25 healthy patients were taken and the maxillary anterior teeth (n = 138) analyzed in the radial plane. The study provided descriptive data on gingival thickness, alveolar bone thickness (horizontal measurements), and vertical measurements related to biologic width.
Results: The mean distance from gingival margin to bone crest (BC) was 3.4 ± 0.7 mm, and that between the cementoenamel junction and BC was 2.6 ± 1.0 mm. The average mid-labial gingival thickness 1 mm apical of the gingival margin was 1.0 ± 0.3 mm; a thinner gingiva was observed in females (P = 0.01) and canines (P < 0.001). The average crestal labial bone thickness was 0.8 ± 0.3 mm. In total, 62% of the tooth sites had a thin gingiva (< 1 mm), and 72% had thin labial bone plates; a moderate positive correlation was found between these parameters (P < 0.001).
Conclusions: CBCT was effective in providing data on the thickness of the labial plate and gingiva as well as on the relationship among BC, CEJ, and gingival margin. The majority of tooth sites had thin labial bone and thin gingiva, with thinner gingiva observed in females and at canine sites.