International Journal of Periodontics & Restorative Dentistry, 01/2020

Typically, healing or temporary abutments are connected and disconnected several times between implant placement and definitive restoration delivery, and soft tissue disruption occurs each time the abutment is disconnected and reconnected. This histologic event is supposed to cause bone resorption around the implant after second-stage surgery. To minimize this clinical scenario, immediately placing and never removing a definitive abutment the day of implant insertion (one-stage protocol) or at second-stage surgery in cases of submerged implants (two-stage protocol) was suggested. This paper details the prosthetic protocol and presents strategies and rationales for placing a definitive abutment the day of implant insertion or at second-stage surgery with cement- and screw-retained restorations. This protocol seems to be an efficient strategy to preserve peri-implant hard and soft tissues. However, positive outcomes in peri-implant bone and soft level changes should be viewed with caution, as their clinical significance is still uncertain.

The peri-implant soft tissue seal consists of a connective tissue cuff and a junctional epithelium that is different from the arrangement of periodontium around a natural tooth. However, the peri-implant soft tissue complex lacks Sharpey's fibers, thus offering less resistance to clinical probing and biofilm penetration compared to the natural dentition. Therefore, the proper restorative emergence profile design is essential to facilitate favorable esthetic outcomes and maintain periimplant health. The aim of this article is to review the currently available evidence related to the design of subgingival (critical and subcritical) and supragingival contours of the implant restorative emergence profile (IREP) as well as provide a flowchart for decision-making in clinical practice. Theoretically, the subgingival contours of the crown/abutment complex should mimic the morphology of the root and the cervical third of the anatomic crown as much and as often as possible. However, this is highly dependent upon the three-dimensional spatial position of the implant relative to the hard and soft tissue complex, in addition to the location of the definitive restoration. Frequently, a convex critical contour is required on the facial aspect of a palatally or incisally positioned implant to support an adequate gingival-margin architecture. Conversely, if the implant is placed too far facially, then a flat or concave contour is recommended. In instances where soft tissue support is not needed, the subcritical area may be undercontoured to increase the thickness, height, and stability of the soft tissue cuff.

The present paper presents clinical guidelines for the selection of the abutment material and level of customization for single-implant reconstructions. A systematic literature search was conducted previous to a Consensus Conference, resulting in two systematic reviews. One review focused on esthetic clinical outcomes, including esthetic indices and linear measurements, and the second focused on peri-implant soft tissue color outcomes, evaluated with spectrophotometry. The outcomes of esthetic indexes and linear measurement were highly heterogenic, hence, a meta-analysis was not feasible. All-ceramic and customized solutions showed a trend for improved results of the esthetic outcomes. Regarding soft tissue color outcomes, all-ceramic abutments induced significantly less soft tissue color changes. Both metallic and all-ceramic abutments/standard and customized components may result in clinically and esthetically acceptable reconstructions.

The clinician's selection of an implant system is influenced by many variables. Ideally, the decision should be based on scientific evidence, but often these decisions are based on economic considerations or influenced by the experience of a trusted peer. The purpose of this paper is to describe the influence of implant neck features (shape and surface) and abutment connection (diameter that matches or is smaller than the implant's platform) on hard and soft tissues around single-tooth implants placed into healed ridges with adequate hard and soft tissue thickness. In an effort to reduce the number of variables, only two-piece implants fully placed at bone level or beneath were taken into consideration. The goal is to provide additional guidance for clinicians on the decision-making and implant-selection processes.

The goal of the study was to compare the outcome of immediate single-implant placement in esthetic sites of patients with thick or thin tissue phenotypes. Forty-one patients underwent implant surgery with guided bone regeneration including peri-implant gap and overcontour grafting. A connective tissue graft was added only for patients with a thin tissue phenotype. Twenty-six patients completed the 12-month follow-up examination (thick, n = 14; thin, n = 12). The thick-phenotype group gained 0.01 ± 1.56 mm of midfacial soft tissue height, while the thin-phenotype group lost 0.20 ± 1.14 mm (P = .21). There was no significant difference in buccal plate thickness achieved at time of uncovery, pink and white esthetic scores, radiographic bone levels, and clinical parameters between the two groups. These results suggest that when the suggested treatment protocol is followed, there are no significant differences in the outcomes of immediate implant placement for patients with different soft tissue phenotypes.

Adequate management of the implant-supported restoration has become an important task when trying to obtain optimal esthetic outcomes. The transgingival area must be developed to maintain or influence the final appearance of the peri-implant soft tissues. Two distinct zones within the implant abutment/crown can be identified: the critical contour and the subcritical contour. Their design and subsequent alteration may impact the peri-implant soft tissue architecture, including the gingival margin level and zenith, labial alveolar profile, and gingival color. Defining these two areas helps clarify how to process soft tissue contours and may additionally improve the necessary communication with the laboratory. Since there are many protocols for placing implants, it is worthwhile to determine similarities in the contouring and macrodesign of their corresponding provisional restorations. Therefore, the purpose of this paper is to discern the general characteristics of the critical and subcritical contours for provisional restorations made for immediate and delayed implants in order to obtain guidelines for daily clinical practice.

The purpose of this study was to evaluate the effect that microgrooved abutments may have on peri-implant tissues. After the flapless extractions of the mandibular premolars of eight dogs, four Laser-Lok implants were placed in each mandibular quadrant, and half of them received laser-microgrooved abutments. A xenograft (MinerOss X, BioHorizons) was used in the gaps. The dogs were euthanized 12 weeks after treatment, and the histomorphometric analysis was performed. Unlike the machined abutments, the microgrooved abutments influenced the orientation of connective tissue fibers, which appeared perpendicularly and adhered to the implant-abutment surfaces, preventing the apical migration of the junctional epithelium. Laser-microgrooved abutments showed superior results.

This prospective randomized controlled clinical trial aimed to compare changes in the horizontal and vertical soft tissue and the alveolar ridge dimension over the course of 12 months following immediate implant placement and temporization with or without simultaneous augmentation with a deproteinized bovine bone mineral with 10% collagen (DBBM-C). Thirty-two patients with a hopeless maxillary anterior tooth and fully intact sockets received an immediate implant and provisional or custom healing abutment after a flapless extraction. Patients were randomized to a control group (n = 16), which received no graft, or to a test group (n = 16), which received DBBM-C grafts. Horizontal and vertical soft tissue changes as well as soft tissue thickness were compared digitally between groups on casts obtained from impressions made at baseline and 3, 6, and 12 months. The test group showed less horizontal dimensional change than the control group; however, the change between the two groups was not statistically significant. Vertical dimensional soft tissue changes from baseline to 12 months showed a statistically significant difference at the distal papilla, favoring the test group. No statistically significant difference was observed for vertical changes between both groups at mesial papillae and midbuccal soft tissue; however, the test group showed lower values overall. No statistically significant differences in soft tissue thickness between groups were detected. Immediate implant placement and temporization with and without adding DBBM-C demonstrate favorable clinical outcomes regarding horizontal and vertical soft tissue changes. Both groups showed loss of tissue volume. Adding DBBM-C in the gap of immediately placed implants slightly lowered the change in tissue parameters, which was not statistically significant, for the first 12 months after implant placement.

This retrospective study evaluated the long-term response of periodontal tissues and survival rate of teeth with advanced attachment loss and pathologic migration in 21 periodontitis patients treated with combined periodontal and orthodontic treatment. All anterior migrated teeth were in function at the end of 10 to 15 years of maintenance. Residual probing depths and clinical attachment levels improved after treatment and remained stable through the follow-up. A total of 55 hopeless teeth were lost during active therapy, as well as 6 molars over the course of the supportive periodontal therapy (for nonperiodontal reasons). In highly compliant patients, all migrated teeth with initial unfavorable prognosis showed long-term clinical stability.

The modified apically repositioned flap (MARF) technique has been previously published as a successful method to increase the zone of attached gingiva with numerous advantages, such as simplicity, predictability, and long-term stability. However, this technique has only been used in areas with at least 0.5 mm of attached gingiva, presurgically. In the current study, the MARF technique was utilized in 21 sites (teeth) with no attached gingiva and only mucosa comprising the marginal tissue. The long-term follow-up results over the course of 1 to 11 years (average follow-up: 3.2 years) show a statistically significant increase of 3.6 ± 0.8 mm for keratinized tissue and of 2.21 ± 0.83 mm for attached gingiva, and no increases in probing depths or marginal tissue recession. These results indicate that the MARF procedure has generated keratinized tissue and attached gingiva in areas with a presurgical absence of these tissues.

The predictability of transcrestal sinus floor elevation (tSFE) in elevating the sinus membrane following posterior maxillary ridge resorption has been widely demonstrated. To minimize complications and increase success, a literature search was conducted to validate procedures used for tSFE. A decision tree based upon timing of perforations was then developed to improve membraneperforation management during the procedure. At each surgical procedure, the clinician is encouraged to use size of the perforation, time during the procedure in which the perforation occurred, and resulting symptoms to determine the best treatment approach. This article discusses all possible sinus membrane perforations based on timing of that surgical procedure, allowing the clinician to recognize and successfully rectify this clinical complication while successfully completing the surgery. With this aim, a classification of sinus membrane perforations occurring during tSFE is proposed, simultaneously providing guidelines to effectively manage these complications.

Soft tissue augmentation procedures are crucial to obtain a successful outcome in implant therapy. The aim of this case series was to describe the 1-year clinical outcomes of a porcine-derived acellular dermal matrix for buccal mucosal thickness augmentation at osseointegrated single implants with facial periimplant soft tissue deficiencies. Ten patients were included and treated with a prosthetic and surgical approach that combined a coronally advanced flap and a dermal matrix. Results showed the possibility to obtain an increase in buccal soft tissue thickness of 1.2 ± 0.18 mm at single implant sites in the esthetic area.

The purpose of this study was to evaluate the intensity of light-curing units and its relationship with the color stability and microhardness of composite resins with different shades subjected to a thermocycling procedure. Eighty blocks (5.0 × 2.0 mm) of TPH Spectrum composite resin (Dentsply Sirona) were produced and distributed into four groups according to the light-curing units (EC 450, ECEL; Valo, Ultradent) and color of the resin material (A3; C3) (n = 20). Within each group, color stability was measured on half the sample (n = 10) using a UV-2450 visible UV spectrophotometer (Shimadzu), and Knoop hardness was measured on the other half (n = 10) using an HMV 2000 microhardness tester (Shimadzu) before and after thermocycling (12,000 cycles, 5°C and 55°C). Mann-Whitney test was performed on the color stability data; the microhardness data were analyzed using a three-way analysis of variance (ANOVA) and Tukey test (α = .05). The ANOVA results showed that thermocycling, distinct light intensity, and different colors of resin materials influenced the microhardness of the composite resins, which was evidenced by the A3 composite resin light-cured with a Valo polywave showing higher hardness values. There was no statistical difference in the color stability of the A3 composite resin; however, the C3 composite resin light-cured with an EC 450 singlewave light-curing unit showed higher color alteration values. In general, the Valo polywave light-curing unit imparted better mechanical property and color stability to both shades of the composite resins. The different shades of resin material influenced the hardness of the composite resins. Therefore, the light intensity of the light-curing units should be evaluated and monitored, as the amount of light intensity will interfere in the quality and longevity of resin restorations.

Eight patients with 38 Miller Class I, II, and III gingival recession defects were treated using an acellular bovine dermal matrix graft (Primatrix, Integra) under a coronal positioned flap. There was a significant 2.43-mm reduction in defect depth, 85.96% mean root coverage, and 65.79% complete root coverage at the 6-month follow-up. Patients reported a significant improvement in perceived esthetics as well as trends for reduced dentinal hypersensitivity, minimal postoperative pain, and overall satisfaction with the procedure. The favorable clinical outcomes and oral biocompatibility would benefit from comparative trials to evaluate the material against contemporary grafting techniques.

Implantoplasty has been claimed as a promising strategy to treat peri-implantitis and prevent progressive peri-implant bone loss. Consequently, the aim of the present case series is to exhibit the clinical outcomes of a 3-year-follow-up resective and implantoplasty therapy applying a novel platform-switch concept to preserve peri-implant tissue integrity and counteract progressive bone loss. Four patients who underwent dental implant therapy and were diagnosed with periimplantitis were treated through access flap surgery, a modified implantoplasty, bone recontouring, and surface decontamination. The radiographic and clinical parameters recorded before and during the 3-year follow-up were: marginal bone loss (MBL) as the primary endpoint, bleeding on probing index (BOP), probing depth (PD), presence of suppuration, pain, mobility, and fracture. The 3-year follow-up exhibited peri-implant bone stability in all cases (100%) showing radiographically an MBL reduction (mean) of 0.8 ± 0.5 mm (mesial) and 0.5 ± 0.3 mm (distal). Mean PD reduction was 4.75 ± 1 mm and mean BOP was reduced by 71%. Pain and suppuration were resolved in all cases. None of the cases reported implant fracture or mobility after the modified implantoplasty therapy. The present case series demonstrated that this modified implantoplasty can be more than a surface decontamination therapy where the narrow and smooth exposed implant surface can counteract peri-implantitis alterations providing favorable biologic conditions to maintain stability of peri-implant tissues.

The aim of this study was to evaluate the effects of different frameworks on the biomechanical behavior of implant-supported provisional single crowns to indicate or not the use of plastic framework as infrastructure. For finite element analysis, a hemi-jaw stone model was scanned and modeled with an external hexagon implant. A framework was screwed onto the implant and a crown was constructed over it. The set was made in triplicate according to framework type: plastic, cobalt-chromium (CoCr), and titanium. Models were exported in volumetric format to analysis software where structures were considered isotropic, linear, elastic, and homogeneous. Axial loads (100, 200, and 300 N) were applied to the fossa bottom, and the system's fixation occurred on the bone base. For strain-gauge analysis, the same hemi-jaw model was built in polyurethane and an implant was placed on it. Three crowns were made, each one with a different framework. Four strain gauges were glued around the implant to obtain microstrain values. The data were analyzed by three-way analysis of variance (ANOVA) and Tukey tests (P < .05). Finite element analysis exhibited microstrain results for bone, von Mises stress values for the implant and screw, and maximum principal stress values for the crown. For computational method, as the applied load increased, so did the stress generated. Titanium frameworks concentrated more stress in the crown and bone, while plastic ones concentrated more in the implant and screw. ANOVA showed that the higher the load value and the framework elastic modulus, the higher the generated microstrain in bone. It can be concluded that all evaluated framework types can be used in the manufacturing of provisional crowns.

The aim of the present study was to compare the effect of traditional orthodontics and Piezocision-assisted orthodontics on the periodontal status and rate of canine retraction. In a split-mouth study, 20 subjects undergoing orthodontic treatment were selected. Conventional orthodontics was performed on 20 canine sites (control side), and contralateral canines were subjected to Piezocision-assisted orthodontics (experimental side). The experimental side showed statistically significant increase in rate of canine retraction as well as an increase in alveolar bone level in mesial and buccal aspects.

The goal of this study was to evaluate the influence of gingival phenotype (GPh) on the clinical outcomes of coronally advanced flap (CAF). In this prospective study, 24 gingival recessions (recession type RT1 class or Miller Classes I and II) in 21 patients were treated with CAF alone. Patients were classified as having thin, medium, thick, or very thick GPh using a color-coded probe. At 6 months, the lowest mean root coverage (mRC; 60.4% ± 28.8%) and complete root coverage (CRC; 25%) were found in patients with thin GPh compared to patients with medium (mRC: 86.4% ± 17.6%; CRC: 60%), thick (mRC: 93.3% ± 14.9%; CRC: 83.3%), and very thick (mRC: 86.7% ± 26.7%; CRC: 80%) GPh. Regression analysis showed a statistically significant difference (P < .05) between thin and thick/very thick GPh in the likelihood of achieving CRC. Higher RES values were observed in patients with thick and very thick GPh (8.2 ± 1.5 and 8.4 ± 1.4, respectively), while thin GPh was related to the lowest RES score (6.3 ± 2.2). CAF performed in patients with thick or very thick GPh resulted in superior clinical and esthetic outcomes than thin and medium GPh. In particular, thin GPh was associated with the lowest mRC, CRC, and root coverage esthetic scores.