Cementum and enamel surface mimicry influences soft tissue cell behavior.

AIMS: To test whether titanium surface roughness disparity might be used to specifically guide the behavior of gingiva fibroblasts and keratinocytes, thereby improving the quality of soft tissue (ST) integration around abutments. METHODS: Titanium discs resembling the roughness of enamel (M) or cementum (MA) were created with normal or increased hydrophilicity and used as substrates for human fibroblasts and keratinocytes. Adhesion and proliferation assays were performed to assess cell-type specific responses upon encountering the different surfaces. Additionally, immunofluorescence and qPCR analyses were performed to study more in depth the behavior of fibroblasts and keratinocytes on MA and M surfaces, respectively. RESULTS: While enamel-like M surfaces supported adhesion, growth and a normal differentiation potential of keratinocytes, cementum-emulating MA surfaces specifically impaired the growth of keratinocytes. Vice versa, MA surfaces sustained regular adhesion and proliferation of fibroblasts. Yet, a more intimate adhesion between fibroblasts and titanium was achieved by an increased hydrophilicity of MA surfaces, which was associated with an increased expression of elastin. CONCLUSION: The optimal titanium implant abutment might be achieved by a bimodal roughness design, mimicking the roughness of enamel (M) and cementum with increased hydrophilicity (hMA), respectively. These surfaces can selectively elicit cell responses favoring proper ST barrier by impairing epithelial downgrowth and promoting firm adhesion of fibroblasts.

Preclinical evaluation of a new synthetic carbonate apatite bone substitute on periodontal regeneration in intrabony defects.

OBJECTIVE: To evaluate the potential of a novel synthetic carbonate apatite bone substitute (CO3 Ap-BS) on periodontal regeneration. BACKGROUND: The use of various synthetic bone substitutes as a monotherapy for periodontal regeneration mainly results in a reparative healing pattern. Since xenografts or allografts are not always accepted by patients for various reasons, a synthetic alternative would be desirable. METHODS: Acute-type 3-wall intrabony defects were surgically created in 4 female beagle dogs. Defects were randomly allocated and filled with CO3 Ap-BS (test) and deproteinized bovine bone mineral (DBBM) or left empty (control). After 8 weeks, the retrieved specimens were scanned by micro-CT, and the percentages of new bone, bone substitute, and soft tissues were evaluated. Thereafter, the tissues were histologically and histometrically analyzed. RESULTS: Healing was uneventful in all animals, and defects were present without any signs of adverse events. Formation of periodontal ligament and cementum occurred to varying extent in all groups without statistically significant differences between the groups. Residues of both bone substitutes were still present and showed integration into new bone. Histometry and micro-CT revealed that the total mineralized area or volume was higher with the use of CO3 Ap-BS compared to control (66.06 ± 9.34%, 36.11 ± 6.40%; p = .014, or 69.74 ± 2.95%, 42.68 ± 8.68%; p = .014). The percentage of bone substitute surface covered by new bone was higher for CO3 Ap-BS (47.22 ± 3.96%) than for DBBM (16.69 ± 5.66, p = .114). CONCLUSIONS: CO3 Ap-BS and DBBM demonstrated similar effects on periodontal regeneration. However, away from the root surface, more new bone, total mineralized area/volume, and higher osteoconductivity were observed for the CO3 Ap-BS group compared to the DBBM group. These findings point to the potential of CO3 Ap-BS for periodontal and bone regeneration.

Adjunctive use of hyaluronic acid in the treatment of gingival recessions: a systematic review and meta-analysis.

OBJECTIVES: To explore the efficacy of Hyaluronic acid as an adjunctive in treatment of gingival recessions (GR). MATERIALS AND METHODS: A systematic literature search was performed in several electronic databases, including Medline/ PubMed, Embase, CENTRAL and LILACS. Recession improvement was evaluated through multiple outcome variables. The Cochrane Risk of Bias tool and the ROBINS-I tool were used to assess the quality of the included trials. Weighted Mean Differences (WMDs) and 95% confidence intervals (CIs) between test and control sites were estimated through meta-analysis using a random-effect model for the amount of Relative Root Coverage (RRC). RESULTS: A total of 3 randomised studies were deemed as eligible for inclusion. Their data were also used for pooling the effect estimates. Overall analysis of RRC (3 studies) presented a WMD of 7.49% (p = 0.42; 95% CIs -10.88, 25.86) in favour of adjunctive use of hyaluronic acid during Coronally Advanced Flap (CAF) technique, although statistical significance was not reached. Statistical heterogeneity was found to be high (I2 = 80%). CONCLUSIONS: Within their limitations, the present data indicate that the local application of Hyaluronic acid does not lead to additional clinical benefits when used as an adjunctive to the treatment of GR with CAF. However, due to the high heterogeneity among the studies, additional well-designed RCTs are needed to provide further evidence on this clinical indication for the use of Hyaluronic acid. CLINICAL RELEVANCE: In the frame of the current review, the adjunctive use of Hyaluronic acid does not additionally improve the clinical outcomes obtained during treatment of GR with CAF.

Clinical periodontal diagnosis.

Periodontal diseases include pathological conditions elicited by the presence of bacterial biofilms leading to a host response. In the diagnostic process, clinical signs such as bleeding on probing, development of periodontal pockets and gingival recessions, furcation involvement and presence of radiographic bone loss should be assessed prior to periodontal therapy, following active therapy, and during long-term supportive care. In addition, patient-reported outcomes such as increased tooth mobility, migration, and tilting should also be considered. More important to the patient, however, is the fact that assessment of signs of periodontal diseases must be followed by an appropriate treatment plan. Furthermore, it should be realized that clinical and radiographic periodontal diagnosis is based on signs which may not reflect the presence of active disease but rather represent the sequelae of a previous bacterial challenge. Hence, the aim of the present review is to provide a summary of clinical and radiographic diagnostic criteria required to classify patients with periodontal health or disease.

Spontaneous regeneration of keratinized tissue at implants and teeth.

AIM: To investigate the spontaneous regeneration of the implanto-mucosal and dento-gingival unit after complete removal of keratinized tissue (KT). MATERIALS AND METHODS: One hemi-mandible per dog (n = 4) was allocated to receive three dental implants (test sites, premolar region), whereas three premolars on the contralateral side were controls. After osseointegration, the entire KT (buccal + lingual) was surgically excised on all test and control sites, leaving the bone exposed. Clinical measurements were performed before excision (T0 ) and after 12 weeks (T1 ). Following healing, the animals were euthanized, and the specimens were histologically processed. Descriptive statistical analyses were performed. RESULTS: Clinical measurements revealed that at T1 , on all teeth, a band of KT was spontaneously regenerated (mean width: 2.60 ± 0.66 mm), whereas on implants, KT was detected only occasionally at mesial or distal but not at buccal sites (mean total: 0.35 ± 0.53 mm; p < .0001). Histologically, spontaneous regeneration of the dento-gingival unit was evident, displaying masticatory mucosa. At the implant sites, on the other hand, the implanto-mucosal unit was characterized by a non-keratinized epithelium and elastic fibres, indicating the characteristics encountered in alveolar mucosa. CONCLUSION: After excision of KT at implant sites, the spontaneous regeneration of the soft tissue is characterized by a non-keratinized epithelium typical for alveolar mucosa, while at tooth sites the spontaneous regeneration was characterized by soft tissue resembling gingiva.

Clinical and radiographic outcomes of implant-supported zirconia fixed dental prostheses with cantilever extension: A proof-of-principle study with a follow-up of at least 1 year.

OBJECTIVES: To test the reliability of full zirconia implant-supported fixed dental prostheses with cantilever extension (FDPCs) after at least 1 year of function. MATERIALS AND METHODS: Thirty-five patients in need of implant-supported single unit crowns (SUC) and FDPCs in posterior areas were enrolled. After implant placement, patients were rehabilitated with screw-retained full-zirconia FDPCs. Implant survival rate, pocket probing depth (PPD), presence/absence of bleeding on probing (BoP), and presence/absence of mechanical/technical complications were recorded. Mesial and distal radiographic marginal bone levels (mBLs) from baseline (i.e., recall appointment 3-6 months after implant loading [T0]) to the follow-up examination (i.e., latest recall appointment after at least 12 months after T0 [T1]), were calculated. RESULTS: Thirty patients with 34 FDPCs (31 SUCs and 3 FDPs) supported by 37 implants were available for analysis after a mean loading time of 2.6 ± 1.5 years (range: 13-87 months). No implants were lost. MBLs and mean PPD values did not change statistically significantly from T0 to T1 from 0.92 mm ± 0.42 to 0.96 mm ± 0.38 (95% CI: -0.07/0.17; p = .418) and from 2.99 mm ± 0.70 to 3.27 mm ± 0.71 (95% CI: -0.11/0.68; p = .25) respectively. Peri-implant mucositis was diagnosed in 22 cases. Screw-loosening and zirconia chipping occurred 1× in 4 patients. CONCLUSION: Within the limitations of the present proof-of-principle study, the use of full-zirconia FDPCs in posterior areas seems a valid and safe short-term treatment option.

Marginal bone level changes around dental implants with one or two adjacent teeth - A clinical and radiographic retrospective study with a follow-up of at least 10 years.

AIM: To compare mean bone level (mBL) changes around dental implants with one or two adjacent teeth after a function time of ≥10 years. MATERIALS AND METHODS: One hundred thirty three periodontally compromised patients (PCPs) with 551 implants enrolled in supportive periodontal care (SPC) were screened. Implants were categorized either into group TIT (tooth-implant-tooth) or into group TIG (tooth-implant-gap). MBL changes from delivery of restoration (i.e., baseline) to follow-up were calculated in millimeters and compared between implants and adjacent teeth. Survival rates and the need for surgical interventions during SPC were recorded. RESULTS: Eighty seven patients with 142 implants were re-evaluated after a mean observation time of 14.5 ± 3.5 years. The mBL at mesial implant sites in the TIT group increased -0.07 ± 0.92 mm and decreased in the TIG group 0.52 ± 1.34 mm, respectively (95% CI: 0.04/1.14, p = .037). At distal implant sites, the mBL in the TIT group increased -0.08 ± 0.84 mm and decreased 0.03 ± 0.87 in the TIG group, respectively (95% CI: -0.20/0.42, p = .48). The overall implant loss rate was 3.5% (n = 5; 2 TIT, 3 TIG), without a statistically significant difference between the two groups (95% CI: 0.18/7.07, p = .892). Tooth loss rates (TIT: 12.3%, TIG: 12.3%) were not statistically significantly different (OR = 1.00, p = .989). CONCLUSION: High tooth and implant survival rates were observed in PCPs. The presence of one or two adjacent teeth seemed to have no impact on marginal bone level changes.

Clinical and histologic evaluation of heterotopic mucosa transpositioning at teeth and dental implants.

AIM: To investigate the healing after heterotopic mucosa transpositioning at dental implants and teeth. MATERIALS AND METHODS: One hemimandible per dog (n = 4) was allocated to receive 3 implants (test), whereby 3 premolars on the contralateral side served as controls. After osseointegration, a Z-plasty was performed on the buccal aspect of the test and control sites to heterotopically move the zone of keratinized tissue (KT) into a region with non-keratinized tissue (nKT) and vice versa. Clinical measurements were performed before (T0) and at 12 weeks following heterotopic transposition (T1). Thereafter, specimens were processed for histological analysis. RESULTS: Clinical measurements revealed that at T1, a band of KT was reestablished at teeth (mean: 2.944 ± 1.866 mm), whereas at implants, the transpositioned nKT resulted in a mucosa without any signs of keratinization (mean: 0 mm; p < .0001). At implant sites, the probing attachment level loss was more pronounced compared to tooth sites (-1.667 ± 1.195 mm and -1.028 ± 0.878 mm, respectively; p = .0076). Histologically, the transpositioned nKT, was accompanied by the formation of KT at the tooth but not at implant sites. The supracrestal soft tissues were statistically significantly higher at tooth compared to implant sites (2.978 ± 0.483 mm and 2.497 ± 0.455 mm, p = .0083). The transpositioned KT remained mostly unaltered in its morphological characteristics. CONCLUSIONS: The findings of this study indicate that: (a) transpositioned KT may retain its morphological characteristics; and (b) transpositioned nKM was accompanied by the formation of KT at the tooth but not at implant sites.

In vitro activity of hyaluronic acid and human serum on periodontal biofilm and periodontal ligament fibroblasts.

OBJECTIVES: A beneficial effect of cross-linked hyaluronic acid (cHA) on periodontal wound healing and regeneration has recently been demonstrated. The present in vitro study was designed to obtain deeper knowledge on the effect of cHA when applied in the gingival sulcus (serum-rich environment) during non-surgical periodontal therapy. MATERIALS AND METHODS: The influence of cHA, human serum (HS), and cHA/HS on (i) a 12-species biofilm formation, (ii) the adhesion of periodontal ligament fibroblasts (PDLF) to dentine surface, (iii) the expression and secretion of interleukin-8, and (iv) the expression of receptors of HA in PDLF and gingival fibroblasts (GF) were evaluated. RESULTS: At 4 h of biofilm formation, cHA and HS in combination (cHA/HS) slightly decreased the colony-forming unit counts in biofilm whereas the metabolic activity of biofilm was reduced in all test groups (cHA, HS, cHA/HS) vs. control. At 24 h, the quantity of biofilm was reduced in all test groups vs. untreated control. The test substances did not affect adhesion of PDLF to dentin. HS increased the expression of IL-8 by PDLF and GF which was partially downregulated by cHA. HS and/or cHA promoted the expression of the HA receptor RHAMM in GF but not in PDLF. CONCLUSIONS: In summary, the present data indicate that serum neither negatively affect the activity of cHA against periodontal biofilm nor had any unwanted influence on the activity of PDLF. CLINICAL RELEVANCE: These findings lend additional support for the positive effects of cHA on cells involved in periodontal wound healing, thus pointing to its potential use in non-surgical periodontal therapy.

Histological evaluation following treatment of recession-type defects with coronally advanced flap and a novel human recombinant amelogenin.

OBJECTIVES: To histologically evaluate the effects of a novel human recombinant amelogenin (rAmelX) on periodontal wound healing / regeneration in recession-type defects. MATERIALS AND METHODS: A total of 17 gingival recession-type defects were surgically created in the maxilla of three minipigs. The defects were randomly treated with a coronally advanced flap (CAF) and either rAmelX (test), or a CAF and placebo (control). At three months following reconstructive surgery, the animals were euthanized, and the healing outcomes histologically evaluated. RESULTS: The test group yielded statistically significantly (p = 0.047) greater formation of cementum with inserting collagen fibers compared with the control group (i.e., 4.38 mm ± 0.36 mm vs. 3.48 mm ± 1.13 mm). Bone formation measured 2.15 mm ± 0.8 mm in the test group and 2.24 mm ± 1.23 mm in the control group, respectively, without a statistically significant difference (p = 0.94). CONCLUSIONS: The present data have provided for the first-time evidence for the potential of rAmelX to promote regeneration of periodontal ligament and root cementum in recession-type defects, thus warranting further preclinical and clinical testing. CLINICAL RELEVANCE: The present results set the basis for the potential clinical application of rAmelX in reconstructive periodontal surgery.

The effect of connective tissue graft or a collagen matrix on epithelial differentiation around teeth and implants: a preclinical study in minipigs.

OBJECTIVES: This study aimed to histologically evaluate the healing at 8 weeks after coronally advanced flap (CAF) with either a superficial (SCTG) or deep palatal connective tissue graft (DCTG), or a collagen matrix (CM) to cover recession defects at teeth and implants. MATERIAL AND METHODS: One mandibular side of 6 miniature pigs received each 3 titanium implants 12 weeks after extraction. Eight weeks later, recession defects were created around implants and contralateral premolars and 4 weeks later randomly subjected to CAF + SCTG, CAF + DCTG, or CAF + CM. After 8 weeks, block biopsies were histologically analyzed. RESULTS: For the primary outcome, i.e., keratinization of the epithelium, all teeth and implants exhibited a keratinized epithelium with no histological differences among them also not in terms of statistically significant differences in length (SCTG 0.86 ± 0.92 mm, DCTG 1.13 ± 0.62 mm, and Cm, 1.44 ± 0.76 mm). Pocket formation was histologically seen at all teeth, around most implants with SCTG and DCTG, however not in the CM implant group. The connective tissue grafts showed hardly signs of degradation, whereas the CM was partly degraded and integrated in connective tissue. The mean gain in gingival height was similar in all experimental groups (SCTG 3.89 ± 0.80 mm, DCTG 4.01 ± 1.40 mm, CM 4.21 ± 0.64 mm). Statistically significant differences were found in the height of the junctional epithelium between the control teeth and the connective tissue groups (p = 0.009 and 0.044). CONCLUSIONS: In this animal model, the use of either a superficial or deep connective tissue graft or a collagen membrane did not seem to have any impact on the epithelial keratinization around both teeth and implants. All procedures (CAF + SCTG/DCTG/CM) resulted in a long JE that was even longer at implants. CLINICAL RELEVANCE: Deep/superficial palatal connective tissue graft yielded similar keratinization around teeth/implants. Given the absence of pocket formation and inflammatory processes at implants when using a CM, CAF + CM might bear potential clinical benefits.

Periodontal microorganisms and Alzheimer disease - A causative relationship?

In the initiation or exacerbation of Alzheimer disease, the dissemination of oral microorganisms into the brain tissue or the low-level systemic inflammation have been speculated to play a role. However, the impact of oral microorganisms, such as Porphyromonas gingivalis, on the pathogenesis of Alzheimer disease and the potential causative relationship is still unclear. The present review has critically reviewed the literature by examining the following aspects: (a) the oral microbiome and the immune response in the elderly population, (b) human studies on the association between periodontal and gut microorganisms and Alzheimer disease, (c) animal and in vitro studies on microorganisms and Alzheimer disease, and (d) preventive and therapeutic approaches. Factors contributing to microbial dysbiosis seem to be aging, local inflammation, systemic diseases, wearing of dentures, living in nursing homes and no access to adequate oral hygiene measures. Porphyromonas gingivalis was detectable in post-mortem brain samples. Microbiome analyses of saliva samples or oral biofilms showed a decreased microbial diversity and a different composition in Alzheimer disease compared to cognitively healthy subjects. Many in-vitro and animal studies underline the potential of P gingivalis to induce Alzheimer disease-related alterations. In animal models, recurring applications of P gingivalis or its components increased pro-inflammatory mediators and ß-amyloid in the brain and deteriorated the animals' cognitive performance. Since periodontitis is the result of a disturbed microbial homoeostasis, an effect of periodontal therapy on the oral microbiome and host response related to cognitive parameters may be suggested and should be elucidated in further clinical trials.

Oral health-related quality of life of patients rehabilitated with fixed and removable implant-supported dental prostheses.

Dental implants have become a mainstream treatment approach in daily practice, and because of their high survival rates over time, they have become the preferred treatment option for prosthetic rehabilitation in many situations. Despite the relatively high predictability of implant therapy and high costs to patients, patient perceptions of success and patient-reported outcome measures have become increasingly significant in implant dentistry. Increasing numbers of publications deal with oral health-related quality of life and/or patient-reported outcome measures. The aim of this paper was to provide an overview of the available evidence on oral health-related quality of life of fully and partially dentate patients rehabilitated with fixed and removable implant-supported dental prostheses. A comprehensive electronic search was performed on publications in English up to 2021. A selection of standardized questionnaires and scales used for the evaluation of oral health-related quality of life were analyzed and explained. The analysis encompassed three aspects: a functional evaluation of oral health-related quality of life, an esthetic assessment of oral health-related quality of life, and a cost-related evaluation of oral health-related quality of life for rehabilitation with dental implants. The data demonstrated that the preoperative expectations of patients markedly affected the outcomes perceived by the patients. As expected, reconstructions supported by implants substantially improved the stability of conventional dentures and allowed improved function and patient satisfaction. However, from a patient's perspective, oral health-related quality of life was not significantly greater for dental implants compared with conventional tooth-supported prostheses. The connection of the implants to the prostheses with locators or balls indicated high oral health-related quality of life. The data also suggest that patient expectation is not a good predictor of treatment outcome. In terms of esthetic outcomes, the data clearly indicate that patients' perceptions and clinicians' assessments differed, with those of clinicians yielding higher standards. There were no significant differences found between the esthetic oral health-related quality of life ratings for soft tissue-level implants compared with those for bone-level implants. Comparison of all-ceramic and metal-ceramic restorations showed no significant differences in patients' perceptions in terms of esthetic outcomes. Depending on the choice of outcome measure and financial marginal value, supporting a conventional removable partial denture with implants is cost-effective when the patient is willing to invest more to achieve a higher oral health-related quality of life. In conclusion, the oral health-related quality of life of patients rehabilitated with implant-supported dental prostheses did not show overall superiority over conventional prosthetics. Clinicians' and patients' evaluations, especially of esthetic outcomes, are, in the majority of cases, incongruent. Nevertheless, patient-reported outcomes are important in the evaluation of function, esthetics, and the cost-effectiveness of treatment with implant-supported dental prostheses, and should be taken into consideration in daily practice.

Effect of combined periodontal and orthodontic treatment of tilted molars and of teeth with intra-bony and furcation defects in stage-IV periodontitis patients: A systematic review.

AIM: To assess the effect of combined periodontal and orthodontic treatment (OT) in stage-IV periodontitis patients. MATERIALS AND METHODS: Three focused questions were addressed using the Population, Intervention, Comparison, Outcome, and Study Design criteria. Randomized controlled trials (RCTs), controlled clinical trials, follow-up studies, case series, and controlled/uncontrolled before/after studies were assessed for inclusion. Primary outcomes included mean changes in pocket probing depth (PPD) and clinical attachment level (CAL). Qualitative synthesis of results was performed and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. RESULTS: Out of 916 records, 1 retrospective case series study reported the effect of OT of tilted molars, 2 RCTs and 10 prospective and 2 retrospective case series studies reported the effect of OT of treated intra-bony defects and 0 articles reported the effect of OT of treated furcation defects. Mean PPD changes were reported in 14 articles, and mean CAL changes were reported in 8 articles. Risk of bias was high in both included RCTs, critical in nine articles, and serious in four articles. No articles included patient-reported outcomes, and three articles reported harms/adverse effects. CONCLUSIONS: Evidence is limited by (i) the lack or low number of included studies, (ii) the apparent methodological and clinical heterogeneity, and (iii) the high risk of bias of the retrieved studies. No solid conclusions could be drawn concerning OT in stage-IV periodontitis patients with respect to tilted molars, teeth with treated intra-bony defects, and teeth with treated furcation defects.

Non-surgical mechanical therapy of peri-implantitis with or without repeated adjunctive diode laser application. A 6-month double-blinded randomized clinical trial.

OBJECTIVES: The objective of this study is to investigate the outcomes following non-surgical therapy of peri-implantitis (PI) with or without adjunctive diode laser application. MATERIALS AND METHODS: A double-blinded randomized controlled clinical trial was carried out in 25 subjects with 25 implants diagnosed with PI. Following curettage of granulation tissue, test implants (T) were treated with adjunctive application of a diode laser for 90 s (settings: 810 nm, 2.5 W, 50 Hz, 10 ms), while at control implants (C) non-activated adjunctive diode laser was applied. The entire treatment procedure was performed at days 0 (i.e., baseline), 7 and 14. The primary outcome measure was change in mean pocket probing depth (PPD). Clinical and microbiological outcomes, as well as host-derived inflammatory markers were evaluated at baseline, 3 and 6 months, while radiographic outcomes were assessed at baseline and at the 6-month follow-up. RESULTS: No statistically significant differences with respect to baseline patient characteristic were observed. After 6 months, both test and control implants yielded statistically significant PPD changes compared with baseline (T: 1.28 and C: 1.47 mm) but without statistically significant difference between groups (p = .381). No statistically significant changes in peri-implant marginal bone levels were detected (p = .936). No statistically significant differences between test and control implants were observed with respect to microbiological and host-derived parameters (p > .05). At the 6-month follow-up, treatment success was observed in 41.7% (n = 5) of test and 46.2% (n = 6) of control patients, respectively (p = .821). CONCLUSION: Repeated adjunctive application of diode laser in the non-surgical management of PI failed to provide significant benefits compared with mechanical instrumentation alone.

Gingival thickness threshold and probe visibility through soft tissue: a cross-sectional study.

OBJECTIVES: The aim was to retrieve the threshold of gingival thickness (GT), where the attribute of gingival translucency through probe visibility was altered. METHODS: In 200 patients, the soft tissue thickness was evaluated at both central mandibular incisors using ultrasound quantification (USD). Additionally, probe visibility was determined using a standard periodontal probe (PB) (CPU 15 UNC, Hu-Friedy), inserted 1 mm deep into the gingival sulcus. Frequencies and relative frequencies were calculated. Repeatability analyses and receiver operating characteristics (ROC) were conducted to determine the USD cut-off point for probe visibility. RESULTS: Regression model indicated that the probe was not visible at a thickness of 0.82 mm for the mandibular left central incisor (95% CIs 0.77, 0.86) and became visible at a thickness of 0.69 mm (95% CIs 0.65, 0.72). The respective values for the mandibular right central incisor were 0.82 mm (95% CIs 0.77, 0.87) and 0.70 mm (0.68, 0.74). ROC analysis confirmed the retrieved regression results by indicating the best fitting balance for specificity and sensitivity at a thickness of 0.8 mm for both mandibular incisors. CONCLUSIONS: In the frame of the current study, the data revealed that gingiva becomes non-transparent at a thickness of approximately 0.8 mm. CLINICAL RELEVANCE: Probe visibility at mandibular incisors for the discrimination between thin and thick soft tissues was correlated with a gingival thickness of 0.8 mm and a high repeatability.

A novel in vitro periodontal pocket model to evaluate the effect of root surface instrumentation on biofilm-epithelial cell interactions.

OBJECTIVE: To develop a novel in vitro periodontal pocket model for evaluating the effect of two different root surface instrumentation modalities on biofilm-epithelial cell interactions. MATERIALS AND METHODS: An artificial periodontal pocket model was created using an impression material. Dentin discs were prepared and incubated for 3.5 days with a biofilm consisting of 12 bacterial strains. Then, the discs were inserted into the pocket model and instrumented for 10 s or 10 strokes either with ultrasonics (US) or hand instruments (HI). Subsequently, a glass slide coated with epithelial cells was placed in close vicinity to the discs. After incubation of the pocket model in a 5% CO2 atmosphere for 6 h, residual bacteria of the biofilm as well as bacteria adhering to or invaded into epithelial cells were determined using colony-forming unit (cfu) counts and real-time PCR. Further, as a parameter of the pro-inflammatory cell response, interleukin (IL)-8 expression was determined by ELISA. RESULTS: Compared to untreated control, HI reduced the cfu counts by 0.63 log10 (not significant) and US by 1.78 log10 (p = 0.005) with a significant difference between the treatment modalities favoring US (p = 0.048). By trend, lower detection levels of Tannerella forsythia were detected in the US group compared to HI. Concerning the interaction with epithelial cells, half of the control and the HI samples showed epithelial cells with attaching or invading bacteria, while US displayed bacteria only in two out of eight samples. In addition, US resulted in significantly lower IL-8 secretion by epithelial cells compared to the untreated control. Between HI and controls, no statistically significant difference in IL-8 secretion was found. CONCLUSION: This newly developed in vitro model revealed in terms of biofilm-epithelial cell interaction after root surface instrumentation that compared to hand curettes, ultrasonic instrumentation appeared to be more effective in removing bacterial biofilm and in decreasing the inflammatory response of epithelium to biofilm. CLINICAL RELEVANCE: Ultrasonic instrumentation might be more advantageous to reduce cellular inflammatory response than hand instruments.

Enamel matrix derivative as adjunctive to non-surgical periodontal therapy: a systematic review and meta-analysis of randomized controlled trials.

OBJECTIVES: To assess the potential additional benefit of the local application of enamel matrix derivative (EMD) on the clinical outcomes following non-surgical periodontal therapy (NSPT) (steps 1 and 2 periodontal therapy). MATERIALS AND METHODS: A systematic literature search was performed in several electronic databases, including Medline/PubMed, Embase, The Cochrane Register of Central Trials (CENTRAL), LILACS, and grey literature. Only randomized controlled clinical trials (RCTs) were eligible for inclusion. Clinical attachment level (CAL) change (primary outcome), probing pocket depth (PPD), and bleeding on probing (BoP) reductions (secondary outcomes) were evaluated. The Cochrane Risk of Bias tool (RoB 2.0) was used to assess the quality of the included trials. Weighted mean differences (WMDs) and 95% confidence intervals (CIs) between test and control sites were estimated using a random-effect model for amount of mean CAL and PPD change. RESULTS: Six RCTs were included for the qualitative analysis, while data from 4 studies were used for meta-analysis. Overall analysis of CAL gain (3 studies) and PPD reduction (4 studies) presented WMD of 0.14 mm (p = 0.74; CI 95% - 0.66; 0.94) and 0.46 mm (p = 0.25; CI 95% - 0.33; 1.26) in favor of NSPT + EMD compared to NSPT alone respectively. Statistical heterogeneity was found to be high in both cases (I2 = 79% and 87%, respectively). CONCLUSIONS: Within their limitations, the present data indicate that the local application of EMD does not lead to additional clinical benefits after 3 to 12 months when used as an adjunctive to NSPT. However, due to the high heterogeneity among the studies, additional well-designed RCTs are needed to provide further evidence on this clinical indication for the use of EMD. CLINICAL RELEVANCE: The adjunctive use of EMD to NSPT does not seem to additionally improve the clinical outcomes obtained with NSPT alone.

Pre-clinical evaluation of the effect of a volume-stable collagen matrix on periodontal regeneration in two-wall intrabony defects.

AIM: To histologically evaluate the effect of a new collagen matrix on periodontal regeneration. MATERIALS AND METHODS: Two-wall intrabony defects were surgically created bilaterally distally to the maxillary first and third pre-molars in beagle dogs. The defects were randomly allocated to open flap debridement either with (test) or without (control) a volume-stable collagen matrix (VCMX). After 12 weeks, the dogs were euthanized, and the specimens histologically processed. Descriptive, histomorphometrical (vertical gain of periodontal tissues) and statistical analyses were then performed. RESULTS: Healing was uneventful in most cases. Residual VCMX was still present and showed integration into new bone, new periodontal ligament, connective tissue and, in some specimens, into new cementum. Periodontal regeneration occurred to a varying extent in both groups. New continuous cementum and new bone formation were statistically significantly greater in the test group (4.12 mm and 3.28 mm, respectively) than in the control group (1.54 mm and 2.47 mm, respectively) (p = .009 and p = .037, respectively). The junctional epithelium was longer in the control group (2.21 mm) than in the test group (1.49 mm, p = .16). CONCLUSION: The present results have for the first time provided histologic evidence for the potential of this novel VCMX to facilitate periodontal regeneration thus warranting further pre-clinical and clinical testing.

Efficacy of laser monotherapy or non-surgical mechanical instrumentation in the management of untreated periodontitis patients. A systematic review and meta-analysis.

OBJECTIVE: To evaluate and compare the effects of laser monotherapy with non-surgical mechanical instrumentation alone in untreated periodontitis patients. MATERIALS AND METHODS: A focused question was formulated based on the Population, Intervention, Comparison, Outcome, and Study design criteria (PICOS): in patients with untreated periodontitis, does laser mono-therapy provide adjunctive effects on pocket probing depth (PPD) changes compared with non-surgical instrumentation alone? Both randomized controlled clinical trials (RCTs) and controlled clinical trials (CCTs) were included. The results of the meta-analyses are expressed as weighted mean differences (WMD) and reported according to the PRISMA guidelines. RESULTS: The search yielded 1268 records, out of which 8 articles could be included. With respect to PPD changes, a meta-analysis including 5 articles (n = 148) failed to identify statistically significant differences in favor of laser monotherapy for PPD change (WMD = 0.14 mm; 95% CI: - 0.04/0.32; z = 1.51; p = 0.132) nor for clinical attachment level (CAL) (WMD = 0.04 mm; 95% CI: - 0.35/0.42; z = 0.19; p = 0.850). Data on cost-effectiveness are lacking. One study reported patient-related outcome measures (PROMS). CONCLUSIONS: In untreated periodontitis patients, laser monotherapy does not yield superior clinical benefits compared with non-surgical mechanical instrumentation alone. CLINICAL RELEVANCE: In untreated periodontitis patients, mechanical instrumentation with hand and/or ultrasonic instruments remains the standard of care.