PubMed-ID: 33969972Seiten: 144-167, Sprache: Englisch
Aim: To investigate whether: 1) in the adhesive era, a full-crown restoration in a molar tooth is more resistant compared with an overlay-type restoration; b) a posterior indirect adhesive restoration (PIAR) is similar to a sound tooth from a mechanical point of view.
Materials and methods: Seventy extracted molars were divided into five groups (1. Butt Joint; 2. Full Bevel; 3. Shoulder; 4. Full Crown; 5. Sound Tooth (control); N = 14) and prepared with four different PIAR overlay design types (according to an adhesthetics classification). Seven expert dentists performed all the preparation and cementation phases with codified protocols. A CAD/CAM workflow was used to realize the 56 monolithic lithium disilicate restorations. The samples were tested with thermomechanical aging (margin quality data will be given in Part 2 of this article series), and the resistance to fracture was then tested and analyzed.
Results and conclusions: In terms of fracture resistance in a situation of overload and within the limitations of the present study, it is possible to conclude that the Full Bevel group showed higher fracture strength than all the other groups. All PIAR restorations performed equally or better than the natural control tooth in the Sound Tooth group. The Full Crown group did not perform better than partial overlay PIAR. The fracture types were limited to the crown in 50% or more of the samples; the rest involved the cervical part of the root. The preparation design that involved the root the least was the Full Crown group (14%).
PubMed-ID: 33969973Seiten: 168-184, Sprache: Englisch
There is a continuing increase in demand for the direct restoration of posterior teeth with resin-based composites. However, the execution of these restorations, especially the reproduction of the anatomical details of the tooth, still presents difficulties for most clinicians. Nowadays, resin-based composite restorations have become increasingly popular due to the development of new materials and filling techniques. Direct composite restorations are usually performed using the time-consuming incremental filling technique, which minimizes polymerization shrinkage. With this technique, the composite is built up in individually cured increments. Due to the superior physical and chemical properties of the newer bulk-fill composites, it is possible to replace this incremental filling technique with a more time-efficient bulk-fill technique, whereby the composite is placed and modeled in a single layer up to the occlusal surface. This article presents this novel technique for direct posterior composite restorations. The technique, called Essential Lines, is simple, esthetic, and time saving. It combines the advantages of the bulk-fill technique with a modeling technique that utilizes minimal so-called diagram lines to restore the tooth anatomy. This procedure can be used by beginners and expert practitioners alike in various clinical situations to produce direct posterior composite restorations with optimal function and esthetics.
PubMed-ID: 33969974Seiten: 186-201, Sprache: Englisch
The restoration of severely damaged teeth with no coronal structure requires an adequate supracrestal tissue attachment (STA) and a distance of at least 3 mm between the crown margin and the alveolar crest. Management of a tooth with no walls and only subgingival tooth structure implies that the tooth has no ferrule. Ferrule preparation from 1.5 to 2.0 mm with a circumference greater than 75% is crucial for a good medium- and long-term prognosis (especially at the anterior segments) and increases survival probability by 5%. Three main options may be considered to create space for a ferrule: crown lengthening, orthodontic extrusion or surgical extrusion. Although extrusion is widely performed with fixed orthodontic appliances using arch wires or elastics attached to the tooth, the same outcome can also be achieved with magnets. This article reports on a 56-year-old male with a severely damaged tooth 23 with no ferrule, which was an abutment of an In-Ceram alumina fixed partial denture (FPD). The treatment plan consisted of a magnetic extrusion of tooth 23 using a provisional tooth-implant FPD made of polymethyl methacrylate (PMMA). The treatment lasted approximately 10 months, with the last clinical and radiographic control carried out 2 years post-extrusion. The present case report aims to demonstrate that magnetic extrusion with an FPD provides a friction-free system in which the direction and amount of force can be manipulated. This technique offers an excellent alternative for the restoration of teeth with insufficient ferrule, or even with no ferrule. Further prospective studies and randomized controlled trials are needed to demonstrate the feasibility of this treatment option.
PubMed-ID: 33969976Seiten: 216-230, Sprache: Englisch
Aim: The altered size, shape or position of the teeth affect their proper alignment, the harmony of the smile, and the dentofacial composition. The aim of this article is to describe a minimally invasive approach to improve the esthetics of a patient through the golden proportion (GP) concept with the use of direct composite resin stratification. Materials and methods: A 26-year-old female complained about the appearance of her smile due to the existing spaces between her anterior teeth; her small, peg-shaped lateral incisors; the wear of her canines; and the color of her teeth. The clinical examination confirmed diastemas in the anterior teeth, peg-shaped maxillary lateral incisors, and incisal wear of the canines. Treatment with dental whitening followed by composite restorations was performed in line with the current conservative approach in dentistry. The patient was followed up for 18 months. Conclusion: The use of the additive technique with composite for the closure of diastemas under the GP concept illustrates an example of viable management to restore esthetic harmony through a minimally invasive approach, with reliability over time and the advantages of being less laborious, less time consuming, and less expensive than other approaches. The treatment plan was acceptable to the patient.
PubMed-ID: 33969977Seiten: 232-242, Sprache: Englisch
Aim: The purpose of the present study was to determine opinions about beauty and attractiveness, to distinguish the rate of variables among gender and age groups, and to evaluate and determine the most attractive lip surface area (SA) and upper to lower lip ratio.
Material and methods: The study was performed in two phases: In phase 1, a set of 10 internet-based frontal facial images were used to generate 5 synthetic images that were distributed to participants, who were asked to choose the most and least attractive image. A total of 312 responses were received in this phase. In phase 2, the images that had been chosen in phase 1 were manipulated to reduce or augment the lip size. Five images had variable lip SA, and three had variable upper to lower lip ratio. A total of 687 responses were received in phase 2.
Results: The majority of respondents preferred a more natural lip SA, while in terms of upper to lower lip ratio, 1:2 was considered the most attractive ratio, and 2:1 the least attractive.
Conclusion: The lips have a great impact on the perception of beauty. Age, gender, trends, and social media all play a role in determining what is considered to be the most attractive lip SA and upper to lower lip ratio.
Clinical significance: The lip SA and upper to lower lip ratios determined in this study may provide guidelines for clinicians in the improvement of facial esthetics. Current trends and social media are the gold standard today regarding patient perception of beauty and esthetics.