Effectiveness of dental floss in the management of gingival health: A 6-month follow-up of a randomized controlled clinical trial.

OBJECTIVES: To evaluate, (i) if subjects submitted to a structured oral hygiene training program (OHt) maintain adopted habits over 180 days without professional guidance; and (ii) in perspective whether flossing provides additional benefits to toothbrushing on gingival health. MATERIALS AND METHODS: Seventy-five adult subjects showing approximately 40% proximal gingival bleeding were randomized to receive OHt (1 session weekly over 8 weeks) using toothbrush and dental floss or toothbrush alone. The subjects were then followed over 180 days without professional guidance. Primary outcomes were mean interproximal Gingival Index (GI) and GI = 2 (gingival bleeding). Mixed linear models were used for the comparison between groups (p < 0.05). RESULTS: 68 subjects received OHt, 48 subjects completed the 180-day follow-up. Subjects maintained adequate oral hygiene routines. Besides a reduction in gingival inflammation, no alterations in gingival status were observed among groups, subjects additionally instructed to use dental floss showing a mean interproximal GI = 2 of 12.8 ± 2.5 compared with 19.8 ± 2.2 for subjects limited to tooth brushing alone. CONCLUSIONS: OHt intensive training promotes gingival health and maintenance lasting at least 6 months without professional supervision reinforcing important principles: (i) dental health professionals should dedicate time training and motivating their patients to reach adequate self-performed plaque control; and (ii) the adjunctive use of dental floss appears essential to reduce interproximal gingival inflammation in subjects with intact interdental papillae. CLINICAL RELEVANCE: Dentists need to invest time in training/motivating/engage their patients to achieve adequate OH; adjunct flossing in subjects with papilla filling the interdental space appears essential to reach and maintain gingival health. CLINICALTRIALS: GOV : (53831716.5.0000.5346). TRIAL REGISTRATION: The protocol registration was filed May 9, 2018 (# 538,311,716.5.0000.5346) on ClinicalTrials.gov. An NCT number (NCT04909840) was generated upon completed registration.

Screening of Hydroxyapatite Biomaterials for Alveolar Augmentation Using a Rat Calvaria Critical-Size Defect Model: Bone Formation/Maturation and Biomaterials Resolution.

BACKGROUND: Natural (bovine-/equine-/porcine-derived) or synthetic hydroxyapatite (HA) biomaterials appear to be the preferred technologies among clinicians for bone augmentation procedures in preparation for implant dentistry. The aim of this study was to screen candidate HA biomaterials intended for alveolar ridge augmentation relative to their potential to support local bone formation/maturation and to assess biomaterial resorption using a routine critical-size rat calvaria defect model. METHODS: Eighty adult male Sprague Dawley outbred rats obtained from a approved-breeder, randomized into groups of ten, were used. The calvaria defects (ø8 mm) either received sham surgery (empty control), Bio-Oss (bovine HA/reference control), or candidate biomaterials including bovine HA (Cerabone, DirectOss, 403Z013), and bovine (403Z014) or synthetic HA/ß-TCP (Reprobone, Ceraball) constructs. An 8 wk healing interval was used to capture the biomaterials' resolution. RESULTS: All biomaterials displayed biocompatibility. Strict HA biomaterials showed limited, if any, signs of biodegradation/resorption, with the biomaterial area fraction ranging from 22% to 42%. Synthetic HA/ß-TCP constructs showed limited evidence of biodegradation/erosion (biomaterial area fraction ≈30%). Mean linear defect closure in the sham-surgery control approximated 40%. Mean linear defect closure for the Bio-Oss reference control approximated 18% compared with 15-35% for the candidate biomaterials without significant differences between the controls and candidate biomaterials. CONCLUSIONS: None of the candidate HA biomaterials supported local bone formation/maturation beyond the native regenerative potential of this rodent model, pointing to their limitations for regenerative procedures. Biocompatibility and biomaterial dimensional stability could suggest their potential utility as long-term defect fillers.

The minipig intraoral dental implant model: A systematic review and meta-analysis.

OBJECTIVES: The objective of this report was to provide a review of the minipig intraoral dental implant model including a meta-analysis to estimate osseointegration and crestal bone remodeling. METHODS: A systematic review including PubMed and EMBASE databases through June 2021 was conducted. Two independent examiners screened titles/abstracts and selected full-text articles. Studies evaluating titanium dental implant osseointegration in native alveolar bone were included. A quality assessment of reporting was performed. Random-effects meta-analyses and meta-regressions were produced for bone-implant contact (BIC), first BIC, and crestal bone level. RESULTS: 125 out of 249 full-text articles were reviewed, 55 original studies were included. Quality of reporting was generally low, omissions included animal characteristics, examiner masking/calibration, and sample size calculation. The typical minipig model protocol included surgical extraction of the mandibular premolars and first molar, 12±4 wks post-extraction healing, placement of three narrow regular length dental implants per jaw quadrant, submerged implant healing and 8 wks of osseointegration. Approximately 90% of studies reported undecalcified incandescent light microscopy histometrics. Overall, mean BIC was 59.88% (95%CI: 57.43-62.33). BIC increased significantly over time (p<0.001): 40.93 (95%CI: 34.95-46.90) at 2 wks, 58.37% (95%CI: 54.38-62.36) at 4 wks, and 66.33% (95%CI: 63.45-69.21) beyond 4 wks. Variability among studies was mainly explained by differences in observation interval post-extraction and post-implant placement, and implant surface. Heterogeneity was high for all studies (I2 > 90%, p<0.001). CONCLUSIONS: The minipig intraoral dental implant model appears to effectively demonstrate osseointegration and alveolar bone remodeling similar to that observed in humans and canine models.

Residual periodontal ligament in extracted teeth - is it associated with indication for extraction?

BACKGROUND: Periodontal disease is a major cause of tooth loss. Few studies have evaluated the residual area of the periodontal ligament in extracted teeth and, to the best of our knowledge, none from Latin America have done so regarding indications for extraction. The aim of this study was to evaluate the residual periodontal ligament (RPL) with respect to indication for extraction in a sample of teeth from a Brazilian Public Health Service district. MATERIALS AND METHODS: All teeth extracted within the Public Health Service district of Santa Maria, Brazil, over a 5-month period were requested for analysis. A total of 414 teeth eligible for measurement were stained and evaluated for RPL using a stereo microscope. Participating Public Health Service dentists completed a questionnaire detailing demographic variables and indication for each extracted tooth. The percentage of RPL was determined for each tooth. Comparisons of RPL between teeth extracted on periodontal versus other indications were made using the Mann-Whitney test. RESULTS: RPL averaged 34.8% for teeth extracted on periodontal indications versus 79.5% for other teeth (P ≤ 0.001). When considering teeth with an RPL ≥ 30% as possible to maintain, 189 (76%) of the teeth extracted on periodontal indications could have been maintained. When RPL cut-off limits of ≥ 40% or ≥ 50% are applied, 93 (37%) and 43 (17%) teeth, respectively, could have been maintained. CONCLUSION: This study suggests that strictly based on RPL, a large number of teeth extracted on periodontal indications conceivably could be maintained.

Effect of self-performed mechanical plaque control frequency on gingival health in subjects with a history of periodontitis: A Randomized Clinical Trial.

AIM: This randomized clinical trial evaluated the effect of the frequency of self-performed mechanical plaque control (SPC) on gingival health in subjects with a history of periodontitis. MATERIALS AND METHODS: Forty-two subjects participating in a routine periodontal maintenance program were randomized to perform SPC at 12-, 24- or 48-hr intervals. Plaque index (PlI) and gingival index (GI) were evaluated at baseline, and days 15, 30 and 90 of study. Probing depths, clinical attachment levels and bleeding on probing were assessed at baseline, days 30 and 90. Mixed linear models were used for the analysis and comparison of experimental groups. RESULTS: Mean GI at baseline remained unchanged throughout study (90 days) only in the 12-hr group (0.7 ± 0.1 versus 0.8 ± 0.1; p < .05). At the end of study, mean GI was significantly increased in the 48-hr group over that in the 12- and 24-hr groups. When GI = 2 scores were considered, only the 48-hr group failed to maintain gingival health throughout the study (18.8%). CONCLUSION: SPC performed at a 12- or 24-hr frequency appears sufficient to controlling gingival inflammation whereas this clinical status was not maintained using a 48-hr frequency in subjects with a history of periodontitis subject to a routine periodontal maintenance program (ClinicalTrials.gov: 50208115.9.0000.5346).

Sinus augmentation using rhBMP-2/ACS in a mini-pig model: Influence of an adjunctive ceramic bone biomaterial.

BACKGROUND: Recombinant human bone morphogenetic protein-2 in an absorbable collagen sponge carrier (rhBMP-2/ACS) has been shown to support significant bone formation when used to augment the maxillary sinus for implant dentistry. Nevertheless, bone biomaterials have been suggested to extend rhBMP-2/ACS with limited support of the merits of such approaches. OBJECTIVES: To evaluate local bone formation/dental implant osseointegration following implantation of rhBMP-2/ACS combined with a ceramic bone biomaterial using a mini-pig sinus augmentation model. METHODS: Twelve adult Göttingen mini-pigs received rhBMP-2/ACS (rhBMP-2 adjusted to 0.43 mg/cc) alone or combined with an off-the-shelf biphasic ceramic (15%/85% HA/ß-TCP) biomaterial at 3:1, 1:1 and 1:3 ratios randomized to contra-lateral maxillary sinus sites yielding rhBMP-2/ACS fractions of 100%, 75%, 50% and 25%, respectively. A 4-cc implant volume was used for all sites. Two threaded dental implants (ø4.0 × 11.5 mm) were placed at each site. The animals were euthanized at 8 weeks for histologic analysis. RESULTS: Surgical execution and healing were generally uneventful, infraorbital local swelling was observed in all animals until suture removal. rhBMP-2/ACS combined with the ceramic biomaterial did not significantly enhance local bone formation (range 9.0 ± 1.5 to 9.7 ± 2.1 mm) compared with rhBMP-2/ACS alone (8.6 ± 1.1 mm; p > 0.05). Variations in rhBMP-2/ACS to ceramic matrix ratios yielding rhBMP-2 doses approximating 0.4, 0.9, 1.3 and 1.7 mg/sinus did not appreciably influence bone formation/osseointegration. CONCLUSIONS: Whereas rhBMP-2/ACS supports significant bone formation/osseointegration in the mini-pig sinus augmentation model and thus appears an effective alternative for sinus augmentation procedures, adding a ceramic biomaterial to rhBMP-2/ACS does not produce meaningful biological advantages.

Screening of candidate biomaterials for alveolar augmentation using a critical-size rat calvaria defect model.

OBJECTIVE: To screen candidate biomaterials intended for alveolar augmentation relative to their potential to enhance local bone formation using a routine critical-size (ø8-mm) rat calvaria defect model. METHODS: One hundred and forty male Sprague Dawley outbred rats, age 11-12 weeks, weight 325-375 g, obtained from USDA approved breeder, randomised into 14 groups of 10 animals, each received one of the following treatments: sham-surgery (empty control), Bio-Oss (bovine HA/reference control), or candidate biomaterials including bovine HA, synthetic HA/ß-TCP and calcium phosphate constructs, mineralised/demineralised human bone preparations, a ß-TCP/calcium sulphate and an HA/calcium sulphate putty. A 4-week healing interval was chosen to discern local bone formation using incandescent and polarised light microscopy. Statistical analysis used one-way ANOVA followed by Bonferroni for pairwise comparisons. RESULTS: Candidate biomaterials all displayed biocompatibility. They exhibited limited, if any, appreciable bioerosion or biodegradation. No statistically significant differences in mean linear defect closure were observed among experimental groups, sham-surgery displaying the highest score (48.1 ± 24.3%). Sham-surgery also showed a significantly greater bone area fraction than all other groups (19.8 ± 13.9%, p < .001). The HA/calcium sulphate putty showed a significantly greater residual biomaterial area fraction than all other groups (61.1 ± 8.5%, p < .01). CONCLUSION: Within the limitations of this animal model, although biocompatible, none of the tested biomaterials enhanced local bone formation beyond the innate regenerative potential of this craniotomy defect.

Implant Drill Characteristics: Thermal and Mechanical Effects of Two-, Three-, and Four-Fluted Drills.

PURPOSE: Avoiding excessive trauma--thermal or otherwise--during dental implant site preparation is considered critical to implant success; overheating is considered to be a major cause of bone necrosis. Studies evaluating thermal and mechanical effects of implant drill design are limited, and effects of flute design have not been accounted for. The purpose of this study was to compare heat generation and cutting efficiency associated with two-, three-, and four-fluted implant drills to investigate the optimal number of flutes. MATERIALS AND METHODS: Two-, three-, and four-fluted dental implant drills with identical point, relief, and rake angles and otherwise standard dimensions were evaluated. Real-time temperature changes while drilling artificial bone were recorded using an infrared thermal imager. Cutting efficiency was assessed as the drilling time to a 15-mm depth under constant load using a specially designed recording system. Each drill variation was examined 20 times. A one-way analysis of variance was used for statistical analysis. RESULTS: Mean temperature increases amounted to 8.3°C, 10.8°C, and 15.1°C for two-, three-, and four-fluted drills, respectively; temperatures significantly increased (P < .001) with an increased number of flutes. Mean drilling time serving as a measure of cutting efficiency amounted to 2.6, 2.5, and 2.5 seconds for the two-, three-, and four-fluted drills, respectively. A trend of cutting efficiency increasing or decreasing according to the number of flutes was not observed. Differences in cutting efficiency among the three drill variations were statistically significant (P = .015). The cutting efficiency of the three-fluted drill was superior to that of the two-fluted drill (P = .016). CONCLUSION: Within the limitations of the study, a two-fluted drill would be preferred for osteotomy preparation due to its level of heat generation, whereas a three-fluted drill showed favorable cutting efficiency.

First-Order Mathematical Correlation Between Damping and Resonance Frequency Evaluating the Bone-Implant Interface.

PURPOSE: Various advanced technologies have been designed to estimate dental implant stability, including insertion torque, implant damping using the Periotest, and resonance frequency analysis expressed in implant stability quotient units. This study aimed to establish the relationship between the estimates for these three techniques. MATERIALS AND METHODS: Bovine cortical bone blocks were trimmed to square shapes of precisely controlled thickness and density. Thereafter, 4-mm-diameter × 10-mm-long implants were placed in the bone blocks using 30-, 45-, and 60-Ncm insertion torques. Implant damping and resonance frequency analysis were conducted at four angles for each implant. Spearman correlation coefficients were calculated to examine the relationship between insertion torque, resonance frequency analysis, and implant damping measured values. RESULTS: Resonance frequency analysis and implant damping estimates exhibited a strong inverse correlation (r = -0.98, P < .001). A linear equation was formulated: Periotest value = 15.54 + (-0.26 × implant stability quotient). Implant damping and resonance frequency estimates revealed a weak correlation with insertion torque (P < .05). CONCLUSION: This study mathematically defined a linear correlation between implant damping and resonance frequency estimates, thereby providing a guide for clinicians when deciding the loading time for dental implants using the implant damping or resonance frequency estimates.

Histological analysis and gene expression profile following augmentation of the anterior maxilla using rhBMP-2/ACS versus autogenous bone graft.

AIM: The objective of this report was to present histological characteristics and gene expression profile of newly formed bone following horizontal augmentation of the atrophic anterior maxilla using recombinant human bone morphogenetic protein-2 in an absorbable collagen sponge carrier (rhBMP-2/ACS) versus an autogenous bone graft (ABG). METHODS: Bone core biopsies from 24 subjects participating in a randomized clinical trial were obtained at dental implant placement, 6 months following alveolar ridge augmentation using rhBMP-2/ACS (rhBMP-2 at 1.5 mg/ml; total dose 4.2 mg) or a particulate ABG harvested from the mandibular retro-molar region. A titanium mesh was used to provide wound stability and space for bone formation. Analysis included histological/histometric observations and gene expression profile of the newly formed bone. RESULTS: rhBMP-2/ACS yielded bone marrow rich in capillaries, undifferentiated cells and bone lining cells compared with the ABG (p = 0.002). Whereas no significant differences were observed in total bone fraction (p = 0.53), non-vital bone particles trapped in lamellar vital bone were observed in the ABG group (p < 0.001). Real-time PCR showed greater BMP-2 and RUNX2 expression for rhBMP-2/ACS over the ABG (p = 0.001 and 0.0021, respectively), while the ABG exhibited greater expression of RANKL:OPG, BSP and OPN over rhBMP-2/ACS (p = 0.01, 0.005 and 0.0009, respectively). CONCLUSIONS: Our observations suggest that formative biological processes explain bone formation following implantation of rhBMP-2/ACS, whereas remodelling, resorptive/formative processes, characterizes sites receiving ABGs.

Biologics and Cell Therapy Tissue Engineering Approaches for the Management of the Edentulous Maxilla: A Systematic Review.

PURPOSE: The aim of this systematic review was to evaluate current and emerging regenerative approaches for implant site development in the edentulous atrophic maxilla using tissue engineering and regenerative medicine (TERM) principles and to identify priorities for future research. MATERIALS AND METHODS: Two independent examiners conducted a comprehensive search using specific keywords to identify original clinical studies using TERM for implant site development in the edentulous atrophic maxilla including indications for alveolar ridge preservation, horizontal alveolar augmentation, maxillary sinus augmentation, and augmentation of severe vertical or combined defects. Endpoints included clinical, radiographic, histologic, and patient-centered outcomes. RESULTS: The initial search identified 3,061 articles. The final selection included 89 articles, of which 12 evaluated alveolar ridge preservation, 6 horizontal defects, 61 maxillary sinus augmentation, and 11 management of severe vertical or combined defects. A summary of the main findings relative to the effect of TERM-based approaches applied for implant site development in the atrophic maxillary segments is presented. Marked heterogeneity among included studies prevented meaningful quantitative analysis. The following relevant effects of TERM-based therapies for site development in the edentulous atrophic maxilla were observed: (1) recombinant human bone morphogenetic protein-2 in an absorbable collagen sponge carrier increased bone augmentation; (2) recombinant human platelet-derived growth factor BB in combination with freeze-dried bone allograft or beta tricalcium phosphate accelerated bone formation through accelerated remodeling of carrier biomaterials; (3) autologous cell therapy enhanced clinical and radiographic outcomes; (4) autologous cell therapy in alveolar ridge preservation provided superior histomorphometric outcomes (vital bone formation) at 6 weeks; and (5) platelet-rich plasma formulations combined with autologous bone grafts for maxillary sinus augmentation increased radiographic density and accelerated bone mineralization at 6 months. CONCLUSION: Clinical success has been demonstrated with the application of different TERM modalities for implant site development in the edentulous atrophic maxilla. However, indications are narrow and further study is needed. Clinical trials assessing meaningful outcomes, involving larger populations, and with longer follow-up are warranted to discern the effectiveness of the achieved results compared with a valid control.

Effect of implant drill characteristics on heat generation in osteotomy sites: a pilot study.

OBJECTIVES: The objective of this study was to evaluate the effect of drill-bone contact area on bone temperature during osteotomy preparation. MATERIAL AND METHODS: Conventional triflute Ø3.6 mm drills were modified with the intent to reduce frictional heat induction. The peripheral dimensions of the drill were reduced 0.15, 0.35 and 0.5 mm to evaluate the effect of surface area on induction of frictional heat between the drill and bone/cutting debris (parameter A). Also, the lateral cutting surface of the drill was set to 0.1, 2 and 7.5 mm to estimate heat induced by direct function of the drill (parameter B). A non-modified triflute drill (parameter A: 0 mm; parameter B: 15 mm) served as control. Thus, nine drills with different A/B combinations vs. one control were tested in artificial bone. Real-time temperature changes (during drilling and withdrawing) were assessed using an infrared thermal imager. Each drilling procedure was performed up to 20 times. Thermal image data were transferred to a PC for simultaneous analysis. RESULTS: Mean temperature changes for all modified drill combinations were smaller than for the control (P<0.001). The effects of parameters A and B were statistically significant (P<0.001). There was a significant interaction effect between the two parameters (P<0.001) showing that the effect of parameter A on the mean temperature changes is different depending on the values of parameter B. As the dimensions of parameter B decreased, the temperature change during drilling also decreased. However, a tendency for the temperature to increase or decrease by parameter A was not observed. CONCLUSIONS: Within the limitations of this pilot study, the observations herein suggest that reduction in contact area between the drill and bone reduces heat induction. Further studies to optimize drill/bone contact dimensions are needed.

Effect of systemic parathyroid hormone (1-34) and a beta-tricalcium phosphate biomaterial on local bone formation in a critical-size rat calvarial defect model.

OBJECTIVE: The objective of this study was to evaluate local bone formation following systemic administration of parathyroid hormone (1-34) (PTH), a surgically implanted synthetic beta-tricalcium phosphate (beta-TCP) bone biomaterial serving as a matrix to support new bone formation. MATERIALS AND METHODS: Critical-size, 8 mm, calvarial through-and-through osteotomy defects were surgically created in 100 adult male Sprague-Dawley rats. The animals were randomized into five groups of 20 animals each to receive one of the following treatments: PTH (15 microg PTH/kg/day; subcutaneously), PTH/beta-TCP, beta-TCP, or particulate human demineralized freeze-dried bone (DFDB), and sham-surgery controls. Ten animals/group were euthanized at 4 and 8 weeks post-surgery for radiographic and histometric analysis. RESULTS: The histometric analysis showed that systemic PTH significantly enhanced local bone formation, bone fill averaging (+/-SE) 32.2+/-4.0% compared with PTH/beta-TCP (15.7+/-2.4%), beta-TCP (12.5+/-2.3%), DFDB (14.5+/-2.3%), and sham-surgery control (10.0+/-1.5%) at 4 weeks (p<0.014). Systemic PTH showed significantly enhanced bone formation (41.5+/-4.0%) compared with PTH/beta-TCP (22.4+/-3.0%), beta-TCP (21.3+/-4.4%), and with the sham-surgery control (23.8+/-4.2%) at 8 weeks (p<0.025). The DFDB group showed significantly increased bone formation from 4 (14.5+/-2.3%) to 8 weeks (32.0+/-3.2%) (p<0.006). The PTH/beta-TCP and beta-TCP groups both showed limited biomaterials resorption. The radiographic analysis was not diagnostic to distinguish local bone formation from the radiopaque beta-TCP biomaterial. CONCLUSIONS: Systemic administration of PTH significantly stimulates local bone formation. Bone formation was significantly limited by the beta-TCP biomaterial.

A descriptive tissue evaluation at maxillary interradicular sites: implications for orthodontic mini-implant placement.

Few studies have evaluated interradicular anatomy for hard and soft tissue thickness. Because interradicular sites are common regions for mini-implant placement for orthodontic anchorage, the purpose of this study was to provide a guideline to indicate the best location for mini-implants as it relates to the thickness of cortical bone and soft tissue, and to the height of the attached gingival field. CT images from 15 men and 15 women (mean age 27 years, range 23-35 years) were used to evaluate the buccal interradicular cortical bone thickness from and mesial to the central incisor to the 1st molar. To record soft tissue depth at the site of assessment for cortical bone thickness, the mucosa was pierced with a #15 endodontic K-file until the attached rubber stop rested on the mucosa. The height of attached gingiva was measured at the mid-aspect of each tooth using a caliper. There were no significant differences in cortical bone thickness within interradicular sites except for the 2nd premolar/1st molar site. There were also no significant differences in soft tissue thickness within interradicular sites except for the lateral incisor/canine and 2nd premolar/1st molar sites. The height of attached gingiva was greater in the anterior compared to the posterior region and was shortest in the premolar region. Given the limits of this study, mini-implants for orthodontic anchorage may be well placed with equivalent bone-implant contact anywhere within the zone of attached gingiva up to 6 mm apical to the alveolar crest with adequate interradicular space.