International Journal of Periodontics & Restorative Dentistry, 05/2024

The introduction of a new collagen substitute, which will potentially reduce the invasiveness of techniques by avoiding the need for a second surgical site (ie, the donor site), needs to be evaluated in relation to the surgical procedure that could benefit the most by utilizing such a matrix. This study compared the clinical outcomes following treatment of RT1 multiple adjacent gingival recessions (MAGRs) using the modified coronally advanced tunnel (MCAT) technique or the multiple coro- nally advanced flap (MCAF) in conjunction with a new volume-stable xenogeneic collagen matrix (VXCM). Secondarily, the study evaluated whether patients report a preference between the two surgical techniques in terms of discomfort. A total of 20 patients requiring treatment of MAGRs were randomly assigned to one of the two treatment groups: MCAF+VCMX (Group A) or MCAT+VCMX (Group B). The following measurements were recorded at baseline (before surgery) and at 6 and 12 months: gingival recession depth (REC), probing pocket depth (PD), keratinized tissue width (KTW), and gingival thickness (GT). Postoperative pain and discomfort were recorded using a visual analog scale (VAS) at 1 week. The primary outcome variable was mean root coverage (mRC), and second- ary outcomes were complete root coverage (CRC), changes in KTW and GT, patient discomfort and satisfaction, and duration of surgery. Healing was uneventful in both groups. At 12 months, both treatments resulted in statistically significant improvements in REC and GT compared to baseline (P < .05). The mRC was 79.95% ± 29.92% in the MCAF group and 64.74% ± 40.5% in the MCAT group (P = .124). CRC was seen in 65.6% of MCAF-treated sites and 52% of MCAT-treated sites (P = .181). Similar clinical results should be expected when MAGRs are treated with MCAF or MCAT, with the adjunct of VCMX. Keywords: biocompatable materials, collagen, gingival recession, mucogingival surgery, periodontal surgery

Implants with deficient papillae and black triangles are common findings. The treatment of these esthetic complications is considered to be challenging with limited predictability. Therefore, the present report aims to describe a novel technique for papilla augmentation: the “iceberg” connective tissue graft (iCTG) after extraction and interproximal bone reconstruction in the anterior region. A 35-year-old patient presented with a hopeless tooth with interproximal clinical attachment loss extending to the apical third of the adjacent tooth. Interproximal bone reconstruction was performed through alveolar ridge preservation by directly applying recombinant human platelet-derived growth factor-BB (rhPDGF-BB) to the exposed root surface of the adjacent tooth. A mixture of autogenous bone chips (obtained from the ramus) and bovine bone xenograft particles (previously mixed with the growth factor) was also used. The patient was able to return for implant therapy only 2 years later, at which time an incomplete regeneration of the interproximal bone was observed. Therefore, to compensate the interproximal deficiency, the iCTG approach was utilized, involving a double layer of CTG with different origins. Two small grafts from the tuberosity were sutured to the mesial and distal ends of a wider CTG harvested from the palate, aiming to gain additional volume at the interproximal sites. The composite graft was then sutured on top of the implant platform, and the flap was then released and closed by primary intention. After conditioning the peri-implant tissues, the case was finalized with a satisfactory outcome. The described iCTG could be an effective approach for reconstructing peri-implant papillae following interproximal bone reconstruction.

The primary aim of this study was to evaluate the efficacy of alveolar ridge preservation (ARP) ther- apy compared with unassisted socket healing (USH) in attenuating interproximal soft tissue atrophy. Adult patients who underwent maxillary single-tooth extraction with or without ARP therapy were included. Surface scans were obtained and CBCT was performed to digitally assess interproximal soft tissue height changes and measure facial bone thickness (FBT), respectively. Logistic regres- sion models were conducted to investigate the individual effect of demographic and clinical vari- ables. Ninety-six subjects (USH = 49; ARP = 47) constituted the study population. Linear soft tissue assessments revealed a significant reduction of the interproximal soft tissue over time within and between groups (P < .0001). ARP therapy significantly attenuated interproximal soft tissue height re- duction compared to USH: –2.0 ± 0.9 mm mesially for USH vs –1.0 ± 0.5 mm mesially for ARP; –1.9 ± 0.7 mm distally for USH vs –1.1 ± 0.5 mm distally for ARP (P < .0001). Thin (≤ 1 mm) facial bone thick- ness (FBT) upon extraction was associated with greater interproximal soft tissue atrophy compared to thick FBT (> 1 mm), independent of the treatment received (P < .0001). Nevertheless, ARP therapy resulted in better preservation of interproximal soft tissue height, especially in thin bone phenotype, by a factor of 2 for the mesial site (+1.3 mm) and by a factor of 1.6 for the distal site (+0.9 mm). This study demonstrated that ARP therapy largely attenuates interproximal soft tissue dimensional re- duction after maxillary single-tooth extraction compared to USH. Keywords: alveolar ridge preservation, bone resorption, dental implants, digital image processing, tooth extraction

The present study aimed to use CBCT to compare the influence of White and Black ethnicity on gingival and bone thickness. A total of 84 individuals of both genders, aged between 18 and 59 years old, were divided into Black (BG; n = 42) and White (WG; n = 42) groups and were analyzed from June 2020 to April 2021. The gingival thickness (GT) and buccal bone plate thickness (BBPT) were measured using CBCT in all maxillary anterior teeth. Mann-Whitney, t test, chi-square, Pearson correlation, and Spearman correlation were used for comparisons and correlations with a 5% signif- icance level. Black individuals had mean GT (1.45 ± 0.29 mm) and BBPT (1.07 ± 0.21 mm) significant- ly thicker (gingival: P < .0001; bone: P = .0002) than White individuals (1.17 ± 0.28 mm and 0.91 ±0.17 mm, respectively). The variables presented greater values for men. A positive correlation be- tween the BBPT and GT was found in two teeth in the WG (left and right central incisors) and one tooth in the BG (left canine). Moreover, a correlation between BBPT and GT immediately below the alveolar bone crest (0 mm) was found in four teeth in the WG (left and right lateral and central incisors) and the BG (left and right canine, left lateral and central incisors). Black race was shown to significantly influence the GT and BBPT, with Black patients presenting thicker structures than White patients.  Keywords: African American, Black, CBCT, gingiva, periodontics

This study compared the survival, marginal bone loss (MBL), and prosthetic complications of 4.5-mm extra-short implants and longer implants splinted to the short implants via the restoration. A retrospective controlled cohort study was performed. The 4.5-mm extra-short group (study group; SG) included 48 consecutively placed implants. The control group (CG) included 48 implants splinted to the extra-short implants. The same surgical team treated the 39 included patients, and all implants were restored with a screw-retained fixed restoration and intermediate abutments. Im- mediate and conventionally loaded implants were included. All implants were in function during the follow-up period (14 ± 3.4 and 17 ± 13 months for SG and CG, respectively). No differences in techni- cal complications were observed between the groups (one and two cases of screw loosening for SG and CG, respectively; two provisional prosthesis fractures for SG; P = .310). Marginal bone stability was similar for SG and CG at the mesial level (–0.01 ± 0.28 mm for SG vs –0.18 ± 0.72 mm for CG; P = .270) and at the distal level (0.02 ± 0.39 mm for SG vs –0.18 ± 0.68 mm for CG; P = .076). The same good clinical performance could be observed for 4.5-mm implants and longer implants under the same prosthesis. Keywords: extra-short implants, marginal bone stability, short dental implants

Mucogingival deformities around implants are frequent findings in clinical practice and often pre- sent as inadequate keratinized tissue and insufficient mucosal thickness. Phenotype modification therapy can increase peri-implant mucosal thickness and the amount of keratinized mucosa, im- proving the long-term clinical outcomes of implants. The free gingival graft (FGG) is considered the gold standard to increase keratinized mucosa; however, FGGs on the lingual aspects of implants are less predictable due to technique sensitivity and often present with insufficient gains in tissue thick- ness due to a limited blood supply. The semilunar lingualized apically positioned flap (SLAP) with subperiosteal tunnel connective tissue graft (CTG) can increase both peri-implant mucosal thick- ness and keratinized mucosal width circumferentially. SLAP consists of one full-thickness, semi- lunar incision within the keratinized mucosa and buccal to the implant, as well as two vertical re- leasing incisions mesial and distal to the implant, extending lingually into the alveolar mucosa. The tissue is apically positioned lingual to the implant and sutured in place, creating buccal space for a CTG via buccal subperiosteal tunneling. SLAP is a minimally invasive and predictable approach for improving the peri-implant mucosal phenotype. This case report demonstrates gains in peri-implant mucosal thickness and the amount of keratinized mucosa over a 10-month period utilizing SLAP with subepithelial CTG. Keywords: case report, connective tissue, dental implant, gingiva, surgical flaps

This technical report describes the simplified subperiosteal sling (SPS) suture for connective tissue graft (CTG) stabilization in root coverage and phenotype modification of single and multiple reces- sion defects via the vestibular incisional subperiosteal tunnel access (VISTA). The simplified SPS suture engages only the CTG and stabilizes it to the tooth in the coronal-most position, inside the subperiosteal tunnel, independent of the overlying gingival tissue. The simplified SPS suture differs from the original SPS suture in that it engages the CTG first, and the needle and tail of the suture are knotted before the suture is introduced into the subperiosteal tunnel. This allows the needle to pass through the subperiosteal tunnel only once from the vestibular access to the intended gingi- val sulcus. When multiple teeth are treated, only one simplified SPS suture traverses the vestibular access at a time, as the CTG is incrementally advanced into the tunnel. This prevents suture entan- glement and improves the practical application of the technique. Keywords: connective tissue graft, periodontal surgery, phenotype modification, root coverage

Healing outcomes of periodontal and implant-related regenerative procedures are closely related to wound stability, which is partially determined by biomechanical properties and behaviors of oral mucosal tissues. Studies on soft tissue behavior under biomechanical forces in oral regeneration models are scarce. Thus, this review aims to (1) contrast the microstructural differences between the attached gingiva (AM) and lining (LM) mucosa; (2) evaluate biomechanical behaviors of the two mucosal types; and (3) relate residual flap tension to the prevalence of wound opening after regenerative procedures. Compositional and structural differences between the AM and LM explain their biomechanical property differences. Wound destabilizers, including tissue recoil stemming from its viscoelastic property, muscle pull, and inflammatory edema (created after the flap-releasing procedure for primary wound closure) interfere with wound stability. Residual flap tension < 0.05 N is a prerequisite for sustained wound closure. Tissues under stress can exert negative cellular changes, resulting in necrosis and wound dehiscence. Biomechanical properties and the variations between AM and LM dictate the degree of wound stability. Efforts should be made to reduce the negative impact of the potential destabilizers to optimize wound stability.  Keywords: biomechanical properties, flap tension, oral mucosa, regenerative procedures, viscoelastic

Numerous surgical techniques have been developed as effective means to facilitate orthodontic treatment, but they may cause significant postoperative discomfort. Piezocision was established as a flapless and minimally invasive technique to accelerate orthodontic tooth movement by com- bining small vertical incisions and piezoelectric corticotomies. Computed tomography is combined with the Piezocision technique to fabricate CAD/CAM surgical guides to prevent iatrogenic damage. A method to combine computer-assisted dynamic navigation with Piezocision is introduced here. CBCT was combined with motion-tracking technology to allow real-time tracing of the piezoelectric instruments during the surgical procedure. This technique delivers the location of the piezoelectric knife in regard to roots and important anatomical structures to increase the safety and accuracy during corticotimies. Keywords: dynamic guidance, navigation, periodontal surgery, piezocision, surgically accelerated orthodontics

This article defines immunophenotypes of stromal inflammatory and endothelial cells and fibroblasts 3 months after augmentation of the peri-implant soft tissue using a porcine cross-linked collagen matrix (VCMX). Peri-implant soft tissue samples were obtained from 12 patients at the lining mucosa (LM)–masticatory mucosa (MM) junction before (1) and 3 months after (2) augmentation. Immunohistochemical stains were performed to identify inflammatory cells (T [CD3] and B [CD20] lymphocytes, plasma cells [CD138]), macrophages (CD68-proinflammatory, CD163-anti-inflammatory/ reparative), endothelial cells (CD31, CD34), and fibroblasts (CD90, TE-7). Differences in the mean positively stained cells pre- and postaugmentation were analyzed by Wilcoxon signed-rank test. CD31+ endothelial cells showed increased mean numbers in MM2 compared to MM1 (P = .025) and in LM2 compared to LM1 (P = .047). CD163+ anti-inflammatory macrophages showed higher mean numbers in MM2 than in MM1 (P = .021) and in LM2 than in LM1 (P = .012). All other cell phenotypes showed nonsignificant changes between pre- and postaugmentation. This molecular study provides novel insight on the frequency of stromal cell phenotypes in the wound healing process at 3 months postaugmentation with VCMX, with anti-inflammatory CD163+ macrophages being predominant. This should be further investigated to help find novel therapeutic approaches to modulate and promote the VCMX-related healing process. Keywords: collagen fibers, collagen matrix, connective tissue, mucosal thickness, soft tissue augmentation