Correlations between alveolar bone microstructure and bone turnover markers in pre- and post-menopausal women

Effect of Bone Microstructure Derived From CBCT on the Accuracy of Robot-Assisted Implant Surgery: A Retrospective Study

OBJECTIVE

The aim of this study was to investigate the influence of bone microstructure on the accuracy of robot-assisted dental implant surgery.

MATERIALS AND METHODS

This retrospective study analyzed 52 patients who received robot-assisted implant surgery between January 2023 and October 2023. Cone beam computed tomography (CBCT) scans were used to evaluate bone microstructural parameters, including the bone volume (BV), tissue volume (TV), bone volume fraction (BV/TV), bone surface (BS), bone surface fraction (BS/BV), trabecular thickness (Tb.Th), and trabecular separation (Tb.Sp). Preoperative and postoperative CBCT data were used to evaluate implant accuracy, and the relationship between bone microstructure parameters and implant deviation including platform deviation, apex deviation, and angular deviation was statistically analyzed.

RESULTS

In robot-assisted implant surgery, BS/BV was a potential facilitator of several implant deviations, while BV/TV and Tb.Th were potential inhibitors of apex global deviation and angular deviation, respectively. Implant deviations were divided into two groups of large and small deviations by median, and the receiver operating characteristic (ROC) curve analysis showed that Tb.Th had the largest area under the ROC for predicting large apex global deviation, 0.711 (p < 0.001), with an optimal cutoff value > 0.179, a sensitivity and specificity of 70.37% and 76.92%.

CONCLUSION

The study concluded that bone microstructure might affect the accuracy of dental implant placement in robotic surgeries. Incorporating bone quality assessments into preoperative planning may enhance the precision and outcomes of implant procedures, highlighting the potential for further refinement in robotic-assisted dental surgery techniques.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: ChiCTR2400085813.

Changes in biomarkers levels from gingival crevicular fluid in pre- and postmenopausal women undergoing orthodontic treatment : A systematic review

PURPOSE

This study aimed to verify whether there is a difference in biomarker levels in the gingival crevicular fluid between premenopausal and postmenopausal women undergoing orthodontic treatment.

METHODS

As eligibility criteria, prospective or retrospective observational studies evaluating women undergoing orthodontic treatment (P), comparing postmenopausal (E) and premenopausal (C) women, and analyzing differences in gingival crevicular fluid biomarkers (O) were included. An electronic search was conducted in seven databases (PubMed, Scopus, Web of Science, LILACS, The Cochrane Library, Embase, and EBSCO: Dentistry & Oral Science) and one grey literature source (Google Scholar). All databases were searched from September 2022 to March 2023. After duplicate exclusion and data extraction, the Newcastle-Ottawa scale was applied to assess the quality and risk of bias, and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) tool was used to verify the certainty of evidence.

RESULTS

Three case-control studies that analyzed receptor activator of nuclear factor kappa‑B ligand (RANKL), osteopontin (OPN), and interleukin (IL)-17A levels were included. One study reported a significant difference for RANKL and another for OPN levels. A third study reported that there was a higher expression of IL17‑A in the postmenopausal group. However, the small number of articles limits our systematic review. The heterogeneity and imprecision in the study results cast doubt on the findings' internal validity.

CONCLUSION

The studies reported alterations in biomarker levels but differed in their conclusions. Therefore, further studies must include other types of bone and inflammatory biomarkers in female patients who are pre- or postmenopausal and undergoing orthodontic treatment.

REGISTRATION

The review was registered at the Open Science Framework ( https://doi.org/10.17605/OSF.IO/Q9YZ8 ).

Menopause-Associated Changes in Mandibular Bone Microarchitecture Are Site-Specific

BACKGROUND

There are conflicting reports on the effects of decreased estrogen levels on mandibular bone microarchitecture. Whether these effects are consistent throughout the mandible is unclear and may have important implications for treatment planning.

PURPOSE

The goal of this study was to evaluate trabecular and cortical bone microstructure in the mandibular condyle and the mandibular basal bone and compare these sites between premenopausal and postmenopausal women.

STUDY DESIGN, SETTING, SAMPLE

Participants were recruited for a cross-sectional cohort study at Columbia University Irving Medical Center. Each participant had cone-beam computed tomography taken of their mandibular condyles and the basal bone. Exclusion criteria for the population included a) current chemotherapy or immunotherapy; b) history of bisphosphonate or other osteoporosis therapy; and c) currently pregnant, nursing, or on hormonal birth control.

INDEPENDENT VARIABLE

The predictor variables are menopausal status (before or after menopause) and mandibular region of interest (condyle/basal bone).

MAIN OUTCOME VARIABLE

Parameters of interest included the following indicators of bone quality: trabecular bone volume fraction, trabecular thickness, trabecular number, trabecular separation, cortical bone volume fraction, cortical thickness, and cortical porosity.

COVARIATES

Covariates included demographic variables such as age, estrogen levels, and ethnicity.

ANALYSES

Quantitative microstructure analyses were conducted on cone-beam computed tomography images, and differences between groups for continuous measures (including age) were assessed with an unpaired t-test, and demographic variables were assessed by χ2. Statistical significance was recorded at P < .05.

RESULTS

The premenopausal and postmenopausal groups each had 31 participants, with the following average age: premenopausal = 43.9 ± 6.9 versus postmenopausal = 57.5 ± 7.6 years old; P < .001, and estrogen levels: premenopausal = 91.77 ± 80.13 pg/ml versus postmenopausal = 41.44 ± 61.62 pg/ml; P < .01). Postmenopausal women had significantly greater condylar trabecular separation (0.61 ± 0.18 vs 0.47 ± 0.11 mm; P < .001) and lower trabecular number (1.03 ± 0.18 vs 1.21 ± 0.19 mm-1; P < .001) compared to premenopausal women. There were no significant differences in the basal bone microarchitectural parameters between the menopausal groups.

CONCLUSION AND RELEVANCE

Menopause is associated with mandibular condylar trabecular bone loss but has minimal effects on the mandibular basal bone. This may have important ramifications for treatment planning in advanced-age individuals.

Associations between cortical bone-to-implant contact and microstructure derived from CBCT and implant primary stability

OBJECTIVES

To evaluate the associations between the cortical bone-to-implant contact (CBIC), bone microstructure derived from cone-beam computed tomography (CBCT), and the primary stability of the implant.

MATERIALS AND METHODS

Twenty-two patients with 65 implants were enrolled in this study. The peak insertion torque values (ITVs) were measured during implant insertion, and the implant stability quotient (ISQ) values were measured immediately after implant placement and 3 months after surgery. The profiles of the peri-implant bone structure were outlined using the volumetric reconstruction of the CBCTs and superimposition of the virtual models, and the features of CBIC and bone microstructure parameters were measured. The linear mixed effects model and generalized estimating equation were used to explore the predictors for implant primary stability.

RESULTS

The average ITV, baseline, and secondary ISQ values were 31.44 ± 6.54 N·cm, 73.34 ± 7.39, and 80.32 ± 4.58, respectively. Statistically significant correlations were found between ITV and surface area of CBIC (r = .340, p = .006), bone volume fraction (r = .294, p = .017), and bone surface fraction (r = -.278, p = .039). Implants with buccolingual CBIC had a higher ITV than implants without CBIC (p = .016). None of the parameters were associated with baseline and secondary ISQ values in generalized estimating equation analysis (all p > .05).

CONCLUSIONS

Within the limitations of the study, preoperative CBCT measurements might enable the prediction of ITV and therefore of implant primary stability values.

Inhibitory Effects of 4-Hexylresorcinol on Root Resorption Induced by Orthodontic Tooth Movement

Root resorption during orthodontic tooth movement (OTM) is caused by an imbalance between the bone turnover rate and applied mechanical stress. The administration of 4-hexylresorcinol (4HR) increases the bone turnover rate and factors associated with bone formation. Thus, 4HR may show protective activity against root resorption during orthodontic tooth movement (OTM). A total of 40 rats (male: 20; female: 20) were included in this study, and the mandibular first molar was subjected to excessive orthodontic force. The experimental group (n = 20) received 12.8 mg/kg of 4HR every 2 weeks. The controls (n = 20) received a solvent without 4HR. Both groups had the same sex distribution. On Day 28 after the initiation of OTM, all the animals were sacrificed for micro-computed tomography analysis, Western blot analysis, and immunohistochemistry. The ratios of the root length and root volume to the total volume were significantly higher in the experimental group compared to those in the control group (p < 0.05). The expression levels of OPG, RANKL, alkaline phosphatase, and Runx2 in the experimental group according to Western blotting were significantly higher in the experimental group compared to those in the control group (p < 0.05). Their expression was mainly found in the periodontal ligament area. In conclusion, the administration of 4HR decreased the root resorption caused by OTM and increased the expression levels of OPG, RANKL, alkaline phosphatase, and Runx2.

Increased Plasma Osteocalcin, Oral Disease, and Altered Mandibular Bone Density in Postmenopausal Women

An association between oral diseases and postmenopausal status has been recognized. However, the relationship between all oral disease, mandibular bone density, health status, and osteocalcin (OCN) bone markers in postmenopausal dental patients has not been reported. This study was therefore to verify the differences in plasma OCN levels, dental, periodontal, and oral mucosal disease, and mandibular bone density alterations from panoramic radiograph and systemic parameters in postmenopausal women, compared to premenopausal women. Oral, radiographic, and blood examination were performed in 92 females. Dental, periodontal, and oral mucosal statuses were recorded. Health profile parameters were collected from medical charts. Plasma OCN was evaluated by enzyme-linked immunosorbent assay. Forty-two (45.7%) participants were postmenopausal with a higher median age (55 (51, 62) years) than the premenopausal group (43 (38, 45) years). Overweight or obesity, hypercholesterolemia, and impaired fasting blood sugar were more prevalent in postmenopause. The average postmenopausal OCN level (425.62 ng/mL) was significantly higher than the premenopausal group (234.77 ng/mL, p < 0.001). The average number of missing teeth, mean attachment loss, alveolar bone loss, periapical lesion count, and clinical oral dryness score were also significantly higher in postmenopause (p=0.008,   < 0.001,  0.031,  0.006,  and 0.005, respectively). However, mandibular bone density determined by mandibular cortical index was lower in postmenopause (p < 0.001). The panoramic mandibular index, mandibular cortical width, fractal dimension, and other oral mucosal disease did not differ between the groups. Postmenopause was associated with elevated plasma OCN (β = 0.504, p < 0.001) when related covariates were adjusted. Elevated plasma OCN, oral mucosal dryness, high number of periapical radiolucencies and missing teeth, and lower mandibular bone density from panoramic radiograph were prevalent in postmenopausal women. Dentists should suspect an increased risk of low bone mineral density in postmenopausal patients who display these clinical and radiographic findings, and they should be referred for further examination. Plasma OCN may interconnect a relationship between postmenopausal status and the low mandibular bone density.

Sex hormone replacement therapy in periodontology-A systematic review

OBJECTIVE

To analyse whether sex hormone replacement therapy (HRT) improves periodontal parameters and dental implants osseointegration in humans.

MATERIALS AND METHODS

Electronic databases and hand searches were performed from June to August 2018 in SciELO, LILACS and PubMed/MEDLINE. Human observational and interventional studies that evaluated the following parameters were included: clinical attachment loss (CAL), probing pocket depth (PPD), bleeding on probing (BOP), radiographic bone loss (RBL) or osseointegration.

RESULTS

Initial search retrieved 1,282 non-duplicated articles. Fifteen studies were selected after inclusion criteria were applied. All studies were performed in postmenopausal women. Mean differences for PPD reduction ranged from 0.02 to 0.2 mm in HRT-positive patients; mean CAL gain -0.18 to 0.54 mm; mean RBL reduction -0.87 to 0.15 mm; and mean BOP reduction 9%-30.3%. Failure rate of dental implants increased -5.5% to 11.21% when HRT was used.

CONCLUSIONS

Very low but consistent evidence suggests a reduction in BOP and no impact on RBL in postmenopausal women receiving HRT. There are inconsistent reports that suggest that HRT in postmenopausal women: (a) improves or does not impact PPD reduction and CAL gain; and (b) does not impact or increase implant loss. In summary, there is no evidence to support HRT prescription for either men or women for periodontal/implant placement purposes.

Long-term structural changes and outcomes of implants in particulate cellular bone and marrow reconstructed jawbone

BACKGROUND

Association between long-term structural changes of grafted bone and outcomes of the implants is not clear.

PURPOSE

Morphometrical measurements and implant success were analyzed in subjects of particulate cellular bone and marrow (PCBM) reconstruction of the jawbone.

MATERIALS AND METHODS

Subjects were 30 implants in 13 patients from a series of 24 PCBM reconstruction cases. The cortical bone thickness and cancellous computed tomography (CT) radiodensity values were retrospectively analyzed from the CT data of 27 subjects. The cumulative success rate of the implants in the PCBM reconstructed cases (pure graft) was compared with that of 127 implants of 56 native bone cases and 42 implants of 28 bone augmentation (partial graft) cases.

RESULTS

In areas of PCBM reconstruction, cancellous CT radiodensity values were significantly high immediately after the surgery, and subsequently the values became stable. Cortical thickness was significantly increased, but did not reach that of native bone. Implant success rates were statistically not different (P = 0.783) between the native bone (91.3%), the partially grafted bone (95.2%), and the PCBM reconstructed bone (93.3%).

CONCLUSION

Implants in pure grafted bone are mainly supported by cancellous bone, because cortical thickness remained thin for a long period of time.

Respective role of membrane and nuclear estrogen receptor (ER) α in the mandible of growing mice: Implications for ERα modulation

Estrogens play an important role in bone growth and maturation as well as in the regulation of bone turnover in adults. Although the effects of 17β-estradiol (E2) are well documented in long bones and vertebrae, little is known regarding its action in the mandible. E2 actions could be mediated by estrogen receptor (ER) α or β. ERs act primarily as transcriptional factors through two activation functions (AFs), AF1 and AF2, but they can also elicit membrane-initiated steroid signaling (MISS). The aim of the present study was to define ER pathways involved in E2 effects on mandibular bone. Using mice models targeting ERβ or ERα, we first show that E2 effects on mandibular bone are mediated by ERα and do not require ERβ. Second, we show that nuclear ERαAF2 is absolutely required for all the actions of E2 on mandibular bone. Third, inactivation of ERαMISS partially reduced the E2 response on bone thickness and volume, whereas there was no significant impact on bone mineral density. Altogether, these results show that both nuclear and membrane ERα are requested to mediate full estrogen effects in the mandible of growing mice. Finally, selective activation of ERαMISS is able to exert an effect on alveolar bone but not on the cortical compartment, contrary to its protective action on femoral cortical bone. To conclude, these results highlight similarities but also specificities between effects of estrogen in long bones and in the mandible that could be of interest in therapeutic approaches to treat bone mass reduction. © 2018 American Society for Bone and Mineral Research.

Trabecular bone microstructure and mineral density in human residual ridge at various intervals over a long period after tooth extraction

BACKGROUND

Long-term changes of trabecular microstructure in human tooth extraction socket have not been investigated.

PURPOSE

To examine the trabecular microstructure of human residual ridges at various intervals following tooth extraction, and to determine whether bone remodeling activity can attain points of relative stability and when such points are reached.

MATERIALS AND METHODS

Forty-four bone biopsy specimens were obtained from lower molar or premolar regions of residual ridges. Postextraction times ranged from 1.6 to 360 months. Samples were analyzed using micro-computed tomography and three-dimensional bone morphometry with histological analyses. Trabecular bone parameters were plotted against postextraction times, and a stepwise piecewise linear regression analysis was performed to determine at which points of time these parameters either increased or decreased.

RESULTS

Using piecewise linear regression, "inflection points" were found in most trabecular bone parameters between 7 and 12 months postextraction. Among the residual ridge samples, woven trabecular structure became mature, consisting of thick lamellar trabeculae with sufficient bone density, under dynamic bone remodeling until the 7th to 12th month post-tooth extraction. After this period, the mature network structure remained stable with low remodeling activity.

CONCLUSION

Bone remodeling of trabecular structure in human residual ridge after tooth extraction had a stabilization period.

Microstructural Observation with MicroCT and Histological Analysis of Human Alveolar Bone Biopsy from a Planned Implant Site: A Case Report

The subject was a 53-year-old male. An alveolar bone sample was obtained from the site of the lower left first molar, before dental implant placement. Although the details of the trabecular structure were not visible with conventional computed tomography, micro-computed tomography (microCT) three-dimensional images of the alveolar bone biopsy sample showed several plate-like trabeculae extending from the lingual cortical bone. Histological observations of the bone sample revealed trabeculae, cuboidal osteoblasts, osteoclasts and hematopoietic cells existing in the bone tissue at the implantation site. Bone metabolic markers and calcaneal bone density were all within normal ranges, indicating no acceleration of the patient’s bone metabolism.

Using microCT, and histological and histomorphometrical techniques, a great deal of valuable information about the bone tissue was obtained from a biopsy sample extracted from the patient’s planned implant site.