International Journal of Periodontics & Restorative Dentistry, 04/2020

This in vivo study assessed the effect of mineral trioxide aggregate (MTA) as a matrix carrier for recombinant human platelet-derived growth factor (rhPDGF) and enamel matrix protein (EMP) on pulp tissue healing following pulp capping. Eighteen intact human premolars scheduled for extraction were included. Coronal access and pulpotomy were performed, and each tooth was left exposed to the oral cavity for 1 hour before pulp capping was performed. Teeth were randomly assigned to one of the following pulp-capping groups (n = 6 each): Group 1 (MTA only); Group 2 (MTA+EMP); or Group 3 (MTA+rhPDGF). Coronal access cavities were then sealed. Immediate preoperative, postoperative, and 4-month follow-up radiographs were taken. At 4 months, the teeth were extracted atraumatically, and histomorphometric and micro-computed tomography (μCT) analyses were performed. Group 1 showed a thin, uneven, irregular dentin-like structure. Its average thickness was 0.3 ± 0.084 mm measured histologically and 0.29 ± 0.091 mm measured by μCT. Group 2 showed of a nonporous, even-thickness dentin-like structure with multiple root-canal obliterations. Highly dense, atubular dentin-like structures associated with presence of odontoblastic lacunae were seen. The structure's average thickness was 0.87 ± 0.09 mm (histologically) and 0.81 ± 0.17 mm (μCT). Group 3 showed a thick and complete 3D continuous seal of newly formed dentin-like structure covering the pulpal space. It resembled secondary dentin in form, porosity, and tubular structural organization, and its average thickness was 0.94 ± 0.02 mm (histologically) and 0.91 ± 0.09 mm (μCT). Groups 2 and 3 showed higher amounts of newly formed dentin-like structure, that was also thicker, than Group 1 (P .05). No statistically significant differences in structure thickness were found between Groups 2 and 3. The nature of the structure can differ if rhPDGF or EMP is added to MTA for pulp-capping purposes. Combination of rhPDGF and MTA resulted in a newly formed structure resembling secondary dentin, whereas a combination of EMP and MTA produced a nonporous, highly dense dentinal-like structure associated with significant root-canal obliterations.

The aim of this retrospective study was to evaluate long-term clinical and radiologic outcomes of submerged and nonsubmerged guided bone regenerative treatments for peri-implantitis lesions. Strict methods of implant-surface decontamination and detoxification were performed. Data on clinical probing depth, soft tissue measures, and marginal bone level that were documented by comparative radiographs were obtained from 45 patients, for a total of 57 implants prior to treatment and at the latest follow-up. The average followup period was 6.9 years (range: 2 to 21 years). Analysis of implant-based data revealed a success rate of 70.2% for a total of 40 implants. Recurrence of periimplantitis was observed on 9 implants, and 8 implants were removed. The regenerative procedures, under a strict periodontal control, were effective in the treatment of moderate to advanced peri-implantitis lesions.

Subgingival margins are often associated with adverse periodontal reactions, such as recession and gingival inflammation. The purpose of this cross-sectional dual-center study was to evaluate the periodontal health and stability of intrasulcular margins, comparing two prosthetic margin preparations: subgingival chamfer (SC) and subgingival feather-edge (SF) with gingival curettage. Ninetysix patients with 205 crowns (buccal margin 0.5 mm into the gingival sulcus) were included in the study. SF, gingival curettage, and intrasulcular restorative margin were prepared on 109 crowns; SC was prepared on 96. Restorations were in place for a mean of 55.9 months (range: 12 months to 10 years). No significant differences were found regarding probing depth between the two groups (mean buccal: 1.6 mm; mean interproximal: 2.3 mm). Significant increased recession was present around SCs, showing a higher margin-exposure frequency (buccal: 19.8% vs 3.7%; interproximal: 5.2% vs 1.4%). SC showed 8.5 times the risk of margin exposure compared to SF, men 5.5 times compared to women, and smokers 3.7 times compared to nonsmokers. Follow-up time was not a significant factor. SC sites showed a tendency for reduced buccal bleeding on probing compared to SF sites (3.0% vs 12.1%), but no significant difference was seen in a regression model. Plaque presence increased the risk of bleeding (4.1×), and women presented a higher risk of bleeding than men (3×). Subgingival margins can provide adequate periodontal health and stability if restorative procedures are well controlled and if patients are enrolled in an adequate maintenance program. SF with intrasulcular margin favors facial soft tissue stability, as reduced gingival recession was observed. The technique should be carefully applied to promote an adequate periodontal response.

Immediate tooth replacement therapy (ITRT), ie, immediate implant placement and provisional restoration in postextraction sockets, has been shown to achieve favorable outcomes in reference to soft tissue stability and esthetics. However, avoiding socket perforation with uniaxial implants in the anterior maxilla can be challenging due to the inherent anatomy. Dual or co-axis subcrestal angle correction (SAC) implants have been developed to change the restorative angle of the clinical crown restoration subcrestally at the implant-abutment interface to enhance the incidence of screw-retained definitive restorations. An additional benefit of this macrodesign implant feature is variable platform switching (VPS) that increases soft tissue gap distance above the implant platform. The purpose of this prospective study on ITRT in maxillary anterior postextraction sockets was to investigate the effect of SAC with VPS (SAC/VPS) compared to conventional platform-switch–design implants (PS) relative to ridge dimension stability and peri-implant soft tissue thickness. A total of 29 patients had undergone ITRT and received either a PS or SAC/VPS implant; previously described measurements were made compared to the contralateral natural tooth sites. When the comparison of buccal soft tissue thickness was made, SAC/VPS showed a greater increase compared to PS (3.12 mm vs 2.39 mm, respectively) with statistical significance (P = .05). The increase was independent from periodontal phenotype. Therefore, SAC/VPS may increase peri-implant soft tissue thickness and help minimize recession following ITRT.

Peri-implant bone dehiscences were grafted either with deproteinized bovine bone mineral (DBBM) block or with particulate DBBM, both covered with a collagen membrane and stabilized with resorbable pins. After 6 months, 17 biopsy samples were included for histologic assessment. Block and particulate DBBM rendered successful tissue integration. Particulate DBBM showed a median of 25.2% of new bone and 31.3% of bone substitute. In the block group, there was a median of 11.5% of new bone and 36.0% of bone substitute. When interpreting the discrepancy in new bone between the groups, the difference in the size of the augmented hard tissue needs to be taken into account.

This report discusses the expanded use of narrow-diameter implants ( 3.0-mm diameter) for permanent use and presents multiple clinical uses for supporting permanent restorations. The increased applications of narrow-diameter implants have expanded the options of treatment available to clinicians based on the patients' needs, desires, and limitations. The advantages, disadvantages, indications, and limitations are presented for the use of these narrow-diameter implants for permanent-case scenarios. These implants can serve as a treatment option in cases where standard-diameter implants cannot be placed due to limitations in volume or size of a planned implant site or due to financially or medically compromised patients.

Immediate tooth replacement therapy (ITRT) in the maxillary anterior sextant is an increasingly frequent treatment option sought by patients and performed by clinicians worldwide. Achieving long-term results that are predictable, stable, esthetic, and healthy is the ultimate goal. This trend also lends itself to minimally invasive surgery as well as defining the procedure to a singular surgical intervention. Preserving and augmenting hard and soft tissues at the time of immediate implant placement provides the best opportunity to achieve these goals. Incorporating an implant with a subcrestal angle correction [SAC] or biaxial feature facilitates screw retention of both provisional and definitive restorations through the cingulum portion of the crown. Compared to uniaxial implants, these implants also feature an extended or variable platform switch [VPS] facially. Measurements of the peri-implant soft tissue thickness 2.0 mm apical to the facial free gingival margin were compared between two groups of 15 consecutively treated patients with different implant designs to evaluate the effect of SAC/VPS for ITRT. The null hypothesis was that there is no difference between uniaxial and biaxial implants with bone grafting and dermis allograft. These authors contend that using a combined hard and soft tissue grafting approach along with SAC/VPS biaxial implants has a synergistic effect on increasing peri-implant soft tissue thickness compared to uniaxial implants.

This case report describes the minimally invasive full fixed rehabilitation of a totally edentulous severely atrophic mandible. The patient refused to undergo any other treatment, from the reconstructive surgery to the removable prosthesis, and asked for a fixed minimally invasive solution in the shortest possible time. Considering that the posterior mandibular bone was inadequate in height and that the interforaminal bone was only 4.3 to 5 mm in height, the patient received four 4-mm-ultrashort implants in the interforaminal area that were immediately loaded. Within all the limitations of this case report this procedure in this specific case appears successful through 2 years of loading.

Peri-implantitis is a biologic complication that can affect the survival of a dental implant. Most surgical and nonsurgical treatments have been relatively ineffective even when using targeted antimicrobial approaches. A growing number of reports are documenting the presence of titanium granules and/or cement in the soft tissues surrounding peri-implantitis–affected dental implants. Two case reports are presented demonstrating how the Nd:YAG or a carbon dioxide (CO2) laser used following regenerative surgeries changed failures into successes as measured by radiographic bone fill and improved clinical parameters. These cases suggest that successful peri-implantitis treatment may need to incorporate decontamination of the soft tissues in addition to the implant's surface. Further studies are warranted to determine if each of these lasers would be successful over a larger patient cohort.

Twenty-six patients with a horizontal ridge defect were entered into this 4-month randomized, controlled, blinded clinical trial to compare a cancellous block allograft to a demineralized bone matrix (DBM) allograft for ridge augmentation. Six patients were excluded from the study, leaving 20 for data interpretation. Both groups had a xenograft overlay and a collagen membrane. For the Block group there was a significant gain of 4.8 ± 1.9 mm (P =.00002; 95% confidence interval [CI]: 3.49 to 6.21), while the DBM group gained 4.6 ± 2.4 mm (P =.0002; 95% CI: 2.88 to 6.36). Vertical change was minimal for both groups (P > .05). The Block group had a mean of 40% vital bone while the DBM group had 35%.

Several approaches for peri-implant soft tissue augmentation have been proposed, including autogenous soft tissue grafts and substitutes. Palatal pedicle flaps have been introduced for increasing facial soft tissue thickness, improving esthetics, and achieving primary closure following alveolar ridge preservation or guided bone regeneration. The main advantage of these approaches is to maintain the vascularization of the flap, which may result in better healing and less shrinkage than graft-based procedures. Nevertheless, different clinical scenarios require different palatal pedicle flaps. The aim of this article was to present several palatal pedicle flap techniques for periimplant soft tissue augmentation and alveolar ridge preservation, showing flap designs and the main advantages through case presentations.

Piezoelectric surgery utilizes ultrasonic vibrations to cut bone more precisely and less traumatically than conventional methods. The regional acceleratory phenomenon following bone injury has a demineralization phase followed by a remineralization phase. Part I of this study on rats assessed the biologic modifications following bone injuries with the piezoelectric knife at 10-Hz and 30-Hz modulation frequencies. Part II focuses on piezoelectric surgery–regulated osteoblast activity and changes occurring in the bone during the regeneration phase. The results indicate that at 30 Hz, the remineralization process starts at day 14 and continues until day 70, with osteoblast progenitor cells observed in the periodontal ligament around acellular new bone as early as day 14. These findings emphasize the potential for regeneration in the late postoperative phase and the possible use of the piezoelectric knife as an adjunct for guided bone regeneration, site development, or site preparation for dental implants.

The free gingival graft (FGG) has been used predictably for gingival procedures aimed to increase the width of keratinized tissue (KT). Several soft tissue alternatives, such as xenografts and allografts, have been studied and proven to be successful with varying degrees. This pilot clinical case series evaluated the efficacy, safety, and initial clinical outcomes (measuring KT width) of a piscine xenograft material (Omega3 Wound, Kerecis) compared to the FGG (harvested from the patient palate) in correcting mucogingival deformities around teeth. A convenience sample of six subjects with unilateral or bilateral lack of KT were enrolled in the study. The primary objective of this pilot study was to determine the gain in width of KT. Secondary objectives included investigating the probing depth, recession depth, bleeding on probing, and inflammation score. There were three FGG sites and six xenograft sites. In bilateral-site treatments, FGG or piscine xenograft were randomly assigned. For unilateral sites, the piscine xenograft was used. Postoperatively, the patients returned for follow-up at 1, 2, 4, 12, 24, 48, and 52 weeks. All six subjects completed the 12-month study and reported uneventful healing. On average, the xenograft sites had a 3.25-mm gain in KT width, and the FGG had an average gain of 3.67 mm. This pilot clinical series showed the piscine xenograft to be safe and efficacious during healing and to increase the width of KT. Future studies may include a more robust study design with a greater number of subjects.

Furcation involvement (FI) is one of the most detrimental factors affecting tooth survival rate over time. Several authors have used the severity of FI for assessing the prognosis of the tooth and the complexity of periodontal disease. While many approaches have been shown to improve the prognosis of furcation-involved teeth, clinical guidelines recommending one treatment or another (based on the horizontal and vertical component of the furcation defects) have not yet been proposed. To this aim, the present article introduces recommendations for the treatment of molars with FI and discusses different treatment options with their potential regenerative approaches. Patient-related factors, together with hard and soft-tissue conditions that may affect the outcomes of periodontal regeneration, are discussed.

Most dental lasers claim that they can aid in hemostasis during oral and periodontal surgery. To date, there are no studies that compare different lasers' ability to congeal pooled blood. The aim of the study was to see if there was a difference in dental lasers' ability to congeal pooled human blood in vitro. Whole blood was collected from donors, with 0.5 mL (premolar socket volume for all tests) aliquoted into microcentrifuge tubes. Different dental lasers (810-nm diode, 940-nm diode, 1,064-nm Nd:YAG, 2,790-nm Er,Cr:YSGG, 2,940-nm Er:YAG, and 10,600-nm CO2) were applied to the whole blood for 0, 15, 30, and 45 seconds. The sample tubes were centrifuged, and the supernatant color was scored to assess the degree of congealing. Additional samples of blood were tested for time needed for maximum congealing and temperature change. Analysis of supernatant colors showed that there were significant differences in the degrees of congealing for the 810-nm diode, 940-nm diode, and 2,790-nm Er,Cr:YSGG lasers when compared to the 1,064-nm Nd:YAG, 2,940-nm Er:YAG, and 10,600-nm CO2 lasers, but not within those groupings. Additionally, the 1,064-nm Nd:YAG laser increased the temperature of the blood samples more than the other lasers and had a shorter time for maximum congealing. There were differences in the dental lasers' ability to congeal pooled human blood in an in vitro model. Nd:YAG, Er:YAG, and 10,600-nm CO2 lasers were able to achieve a greater degree of congealing at an earlier time point. The Nd:YAG laser produced the most heat and was the fastest to complete coagulation.

Placement of short implants is a common approach to rehabilitate edentulous areas. The objective of this study was to evaluate the long-term survival of 7.0- and 8.5-mm implants placed in either a delayed or immediate loading protocol. Life table analysis revealed the implants treated with the delayed loading protocol had a 90.9% survival rate and the implants treated with the immediate loading protocol had a survival rate of 92.0%. The results of this 8-year prospective study demonstrate similar survival rates of short, cylindrical threaded implants placed by either a delayed or immediate loading protocol.

The aim of this retrospective study was to evaluate the alveolar dimensions of the mandibular molar using cone beam computed tomography (CBCT) for immediate implant placement. The width of buccal (WB) and lingual (WL) bone; width of interradicular bone 2 and 4 mm apical to the furcation and at the apex (IRB2, IRB4, and IRBA, respectively); and distance to the inferior alveolar nerve from the furcation (IAN-F) and mesial (IAN-M) and distal (IAN-D) roots were evaluated from CBCT records of 126 subjects (200 mandibular first molars). Mean WB (0.84 ± 0.39 mm) and WL (2.71 ± 1.17 mm) measurements showed significant differences (P = .003). Differences between IAN-F, IAN-M, and IAN-D measurements averaged at 14.14 ± 2.57 mm, 4.31 ± 1.06 mm, and 4.61 ± 1.02 mm, respectively. IRB2, IRB4, and IRBA dimensions were 1.93 ± 0.65 mm, 2.54 ± 0.9 mm, and 4.46 ± 1.91 mm, respectively. The findings of the study demonstrate the alveolar bone morphology of the mandibular first molar and the need for CBCT scans for proper treatment planning for immediate implant placement.

The objective of this study was to evaluate the effect of periodontally accelerated osteogenic orthodontics (PAOO) on gingivae and alveolar bone by analysis of clinical and cone beam computed tomography (CBCT) parameters in the treatment of 20 skeletal Class III patients. The patients included in this study were divided into test and control groups. Periodontal parameters such as probing depth (PD), gingival recession (GR), keratinized gingival width, and alveolar bone thickness of CBCT scans were measured and recorded preoperation (T0) and at 6 months postoperative (T1). The difference in PD from T0 to T1 between the two groups was not statistically significant (0.01 ± 0.46 mm vs 0.22 ± 0.65 mm, respectively; P > .05). No significant difference in GR was observed from T0 to T1 between the two groups (0.03 ± 0.26 mm vs –0.03 ± 0.27 mm, respectively; P > .05). Alveolar bone thickness (4 mm apical to the cementoenamel junction [CEJ]) change from T0 to T1 was –0.31 ± 0.35 mm for the control group and 0.06 ± 0.69 mm for the test group (P .05). Meanwhile, alveolar bone thickness (6 mm apical to CEJ) changes from T0 to T1 were –0.38 ± 0.54 mm and 0.10 ± 0.80 mm for the control and test groups, respectively (P .05). It was determined that PAOO in the treatment of skeletal Class III patients is effective and safe to periodontium on the basis of clinical and CBCT parameters.

The aim of this study was to test the nano-hydroxyapatite powder decontamination method on intraorally contaminated titanium discs and to compare this method with current decontamination methods in the treatment of peri-implantitis. Contaminated discs were assigned to six treatment groups (n = 10 each): titanium hand curette; ultrasonic scaler with a plastic tip (appropriate for titanium); ultrasonic scaler with a plastic tip (appropriate for titanium) + H2O2; short-term airflow system (nano-hydroxyapatite airborne-particle abrasion for 30 seconds); long-term airflow system (nano-hydroxyapatite airborne-particle abrasion for 120 seconds); Er:YAG laser (120 mJ/pulse at 10 Hz). There were also two control groups (n = 10 each): contaminated disc (negative control) and sterile disc (positive control). Scanning electron microscopy, energy-dispersive x-ray spectroscopy, and dynamic contact angle analysis were used to determine the most effective surface-treatment method. The highest percentage of carbon (C) atoms was observed in the negative control group, and the lowest percentage of C atoms was found in the long-term airflow group, followed by the short-term airflow, laser, ultrasonic + H2O2, ultrasonic, and mechanical groups. When the groups were examined for wettability, the lowest contact angle degree was observed in the long-term airflow, short-term airflow, and laser groups. Nano-hydroxyapatite and laser treatments for detoxifying and improving infected titanium surfaces may show the most suitable results for reosseointegration.