NLRP3 deficiency improves bone healing of tooth extraction sockets through SMAD2/3-RUNX2 mediated osteoblast differentiation.

Impaired bone healing following tooth extraction poses a significant challenge for implantation. As a crucial component of the natural immune system, the NLRP3 inflammasome is one of the most extensively studied Pattern-Recognition Receptors (PRRs), and is involved in multiple diseases. Yet, the role of NLRP3 in bone healing remains to be clarified. Here, to investigate the effect of NLRP3 on bone healing, we established a maxillary first molar extraction model in wild-type (WT) and NLRP3KO mice using minimally invasive techniques. We observed that NLRP3 was activated during the bone repair phase, and its depletion enhanced socket bone formation and osteoblast differentiation. Moreover, NLRP3 inflammasome activation was found to inhibit osteogenic differentiation in alveolar bone-derived mesenchymal stem cells (aBMSCs), an effect mitigated by NLRP3 deficiency. Mechanistically, we established that SMAD2/3-RUNX2 signaling pathway is a downstream target of NLRP3 inflammasome activation, and SMAD2/3 knockdown partially reversed the significant decrease in expression of RUNX2, OSX, and ALP induced by NLRP3. Thus, our findings demonstrate that NLRP3 negatively modulates alveolar socket bone healing and contribute to the understanding of the NLRP3-induced signaling pathways involved in osteogenesis regulation.

Biodegradable Nanoflowers with Abaloparatide Spatiotemporal Management of Functional Alveolar Bone Regeneration.

Post-extraction alveolar bone atrophy greatly hinders the subsequent orthodontic tooth movement (OTM) or implant placement. In this study, we synthesized biodegradable bifunctional bioactive calcium phosphorus nanoflowers (NFs) loaded with abaloparatide (ABL), namely ABL@NFs, to achieve spatiotemporal management for alveolar bone regeneration. The NFs exhibited a porous hierarchical structure, high drug encapsulation efficacy, and desirable biocompatibility. ABL was initially released to recruit stem cells, followed by sustained release of Ca2+ and PO43- for in situ interface mineralization, establishing an osteogenic "biomineralized environment". ABL@NFs successfully restored morphologically and functionally active alveolar bone without affecting OTM. In conclusion, the ABL@NFs demonstrated promising outcomes for bone regeneration under orthodontic condition, which might provide a desirable reference of man-made "bone powder" in the hard tissue regeneration field.

Key insights into antiresorptive drug use and osteonecrosis in osteoporotic patients undergoing tooth extractions: A clinical and CBCT assessment.

This study investigates the effects of antiresorptive drugs and risk factors for medication-related osteonecrosis of the jaws in osteoporotic patients undergoing tooth extraction. Among the findings, antiresorptive-treated patients had thicker lamina dura and longer healing times. Additionally, corticosteroid intake and multi-rooted teeth carried a higher osteonecrosis risk. Bone sequestrum indicated osteonecrosis. PURPOSE: To describe the effects of antiresorptive drugs (ARD) in the maxilla and mandible and risk factors for medication-related osteonecrosis of the jaws (MRONJ) in osteoporotic patients undergoing tooth extractions using clinical data and cone beam computed tomography (CBCT). METHODS: This retrospective cohort study collected clinical and CBCT data from 176 patients. The study group (n = 78; 224 extractions) received ARD treatment, underwent tooth extraction, and had a pre-operative CBCT. Additionally, age-, sex-, and tooth-matched controls were selected (n = 98; 227 extractions). Radiographic examinations were performed independently by three calibrated examiners. Statistical analysis included Chi-square, Fisher's exact, Mann-Whitney U, and t-tests to contrast clinical and radiographic data between study and control, MRONJ + and MRONJ - , and bisphosphonate and denosumab patients/sites. Significance was set at p ≤ 0.05. RESULTS: From the study group, 4 patients (5%) and 5 sites (2%) developed MRONJ after tooth extraction. ARD-treated patients exhibited significantly more thickening of the lamina dura and a longer average mucosal healing time (4.4 weeks) than controls (2.6 weeks). In the study group, MRONJ risk significantly increased with corticosteroid intake and in multi-rooted teeth. No significant differences between bisphosphonates and denosumab use were seen in the tomographic features (p > 0.05). Lastly, bone sequestrum was exclusively observed in osteoporotic patients, who exhibited post-operative exposed bone or histological evidence of osteonecrosis. CONCLUSION: Osteoporotic patients under ARD may exhibit thickening of the lamina dura and prolonged post-operative healing. Among these patients, multi-rooted teeth are at higher risk for MRONJ than single-rooted teeth. Sequester formation is a radiographic indicator of osteonecrosis.

Impact of smoking on cost-effectiveness of 10-48 years of periodontal care.

The study aims were (1) to explore whether "periodontal treatment" consisting of surgical therapy (flap, resective, or regenerative) or scaling and root planing treatment with long-term periodontal maintenance treatment, is cost-effective in terms of preventing periodontitis-attributable tooth extraction and replacement by implant-supported crowns ("extraction/replacement"); (2) to assess the effect of cigarette smoking on this cost-effectiveness. Data for this observational retrospective study were collected from dental charts of patients who had received periodontal therapy and at least annual follow-up visits for >10 years were analyzed by linear regression generalized estimating equations and generalized linear models. Among 399 adults (199 males, 200 females), those with the least mean annual treatment cost experienced the greatest mean annual costs for extraction/replacement, indicating general cost-effectiveness. Cigarette smoking adversely impacted this cost-effectiveness, with current heavy smokers experiencing no cost-effectiveness. Former smokers with Grade C periodontitis benefitted most, whereas smoking did not influence cost-effectiveness for Grade B periodontitis. Assessed by mean annual costs of "extraction/replacement," periodontal treatment was cost-effective, which decreased in a dose-response manner by former and current smoking intensity. Cigarette smoking should be factored into treatment planning and cost-effective analyses of periodontal treatment. Smoking cessation should be encouraged.

The influence of different extraction indications on the morphological changes in the maxillary sinus: A retrospective cohort study.

AIMS: The comprehensive effects of maxillary posterior tooth extraction on the maxillary sinus (MS) morphology remain to be thoroughly elucidated. This retrospective cohort study aimed at evaluating the influence of different extraction indications on the morphological changes in the MS by utilizing cone-beam computed tomography (CBCT). METHODS: One hundred and seventy-eight of maxillary posterior tooth extractions underwent CBCT scans before and after extraction using 3D Slicer software. Parameters such as maxillary sinus pneumatization (MSP, the primary outcome measure), buccal bone height (BBH), palatal bone height (PBH), mucosal thickness (MT), and other anatomical structures were measured for patients undergoing extraction due to periodontitis, periapical lesions, or tooth fracture. Multiple linear regression analysis was employed to assess the effect of extraction indications on the MS. RESULTS: While the primary outcome, MSP, did not reveal statistically significant differences across various indications for tooth extraction (p > .05), extraction itself resulted in MSP (p < .05). The rate of this pneumatization was influenced by the position of the extraction site (p < .05). Additionally, baseline values of bone height and mucosal thickness showed an inverse correlation with the rate of change in these parameters following tooth extraction (p < .001). CONCLUSIONS: Tooth extraction led to increased pneumatization of the maxillary sinus while simultaneously reducing bone height and mucosal thickness. However, these outcomes were not influenced by the reason for tooth extraction.

Do oral conditions influence the incidence of bloodstream infection after hematopoietic stem cell transplantation? A retrospective study in Japan.

PURPOSE: This study aimed to evaluate the incidence of bloodstream infection (BSI) among patients undergoing hematopoietic stem cell transplantation (HSCT) for teeth indicated for extraction. METHODS: Patients who underwent HSCT at Toranomon Hospital (Tokyo, Japan) between January 2017 and December 2019 were retrospectively evaluated. The incidence of BSI among patients with teeth indicated for extraction who did not undergo extraction (oral high-risk group) and patients who did not have this risk (oral low-risk group) was compared. RESULTS: Among the 191 consecutive patients included in this study, 119 patients were classified as undergoing high-risk transplantation. BSI after HSCT was observed in 32 out of 60 (53.3%) patients and 56 out of 131 (42.7%) patients in the oral low-risk and oral high-risk groups, respectively (p = 0.173). Multivariable analyses revealed that the presence of > 3 teeth as intraoral sources of infection and age over 50 years were determinants of BSI originating from the oral cavity after engraftment (odds ratio [OR], 9.11; 95% confidential interval [CI] 2.27-36.61]; p = 0.002; OR, 3.22; CI [1.47-7.08], p = 0.004, respectively). CONCLUSION: In patients undergoing HSCT, the presence of less than three intraoral sources of infection did not affect the incidence of BSI after HSCT.

Risk factors for gingival invagination: A retrospective study.

AIM: This study aimed to identify the risk factors for gingival invagination during orthodontic treatment after premolar extraction. MATERIALS AND METHODS: The medical records of 135 patients who had undergone interdental space closure after premolar extraction were collected, and cone beam computed tomography was performed to determine the presence of gingival invagination. The risk factors were examined using mixed-effects models and generalized propensity score weighting (GPSW) to develop a predictive model. RESULTS: Univariate analysis revealed that the extraction site, buccal bone thickness 4 mm apical to the cemento-enamel junction (MB1), mid-root buccal bone thickness (MB2) and vertical skeletal relationships were related to gingival invagination (p < .05). Furthermore, a subsequent multivariable mixed-effects model analysis indicated a significantly increased risk of gingival invagination at MB1 < 1 mm (p < .001; odds ratio [ORMB1≤0.5mm] = 29.304; 95% confidence interval [CI]: 8.986-93.807; OR0.5

Efficacy and safety of a new heterologous fibrin biopolymer on socket bone healing after tooth extraction: An experimental pre-clinical study.

AIM: To assess the efficacy of heterologous fibrin biopolymer (HFB) in promoting alveolar bone healing after tooth extraction in rats. MATERIALS AND METHODS: The upper right incisors of 48 Wistar rats were extracted. Toothless sockets were filled with HFB (HFBG, n = 24) or blood clot (BCG, n = 24). The tooth extraction sites were subjected to micro-computed tomography (micro-CT), histological, histomorphometric and immunohistochemical (for Runt-related transcription factor 2/Runx2 and tartrate-resistant acid phosphatase/TRAP) analyses on days 0, 7, 14 and 42 after extraction. RESULTS: Socket volume remained similar between days 0 and 14 (69 ± 5.4 mm3), except in the BCG on day 14, when it was 10% lower (p = .043). Although the number of Runx2+ osteoblasts was high and similar in both groups (34 × 102 cells/mm2), the HFBG showed lower inflammatory process and osteoclast activity than BCG at 7 days. On day 14, the number of Runx2+ osteoblasts remained high and similar to the previous period in both groups. However, osteoclast activity increased. This increase was 55% lower in the HFBG than BCG. In the BCG, the presence of an inflammatory process and larger and numerous osteoclasts on day 14 led to resorption of the alveolar bone ridge and newly formed bone. On day 42, numbers of Runx2+ osteoblast and TRAP+ osteoclasts decreased dramatically in both groups. Although the BCG exhibited a more mature cortical bone formation, it exhibited a higher socket reduction (28.3 ± 6.67%) and smaller bone volume (37 ± 5.8 mm3) compared with HFBG (socket reduction of 14.8 ± 7.14% and total bone volume of 46 ± 5.4 mm3). CONCLUSIONS: HFB effectively suppresses osteoclast activity and reduces alveolar bone resorption compared with blood clot, thus preventing three-dimensional bone loss, particularly during the early healing period. HFB emerges as a promising biopharmaceutical material for enhancing healing processes after tooth extraction.

Ridge preservation in periodontally compromised molar sockets with and without primary wound closure: A comparative controlled clinical trial.

OBJECTIVE: This study aimed to compare hard- and soft-tissue changes after ridge preservation in periodontally compromised molar sockets with and without primary wound closure. MATERIALS AND METHODS: Forty molars with severe periodontitis requiring extraction were included and allocated to two treatment modalities. After tooth extraction, the sockets were filled with deproteinized bovine bone mineral and covered with a bioabsorbable porcine collagen membrane. Primary wound closure was achieved in the control group, whereas the test group underwent minimally invasive open healing. The dimensions of the bone and soft tissue were recorded at baseline and 6 months. RESULTS: Over 6 months, the control and test groups had similar mean ridge heights at the center of sockets of 8.59 ± 2.47 mm and 8.47 ± 2.51 mm, respectively. The total volume of the control group increased from 1070.17 to 1713.52 mm3 for a mean gain of 643.35 mm3 , whereas that of the test group increased from 992.51 to 1514.05 mm3 for a mean gain of 521.54 mm3 . Compared with the test group, the control group showed a statistically significant decrease in keratinized tissue width of 1.08 ± 1.63 mm. CONCLUSIONS: Bone dimensional changes following ridge preservation with and without primary wound closure were comparable. ARP without primary wound closure preserves more keratinized tissue than that with (Chinese Clinical Trial Registry: ChiCTR-ONN-16009433).

Alveolar ridge preservation versus early implant placement in single non-molar sites: A systematic review and meta-analysis.

OBJECTIVES: The aim of this systematic review and meta-analyses was to evaluate the outcomes of alveolar ridge preservation (ARP) following extraction of non-molar teeth in comparison to early implant placement (EIP) in terms of clinical and radiographic changes, need for additional augmentation at the time of implant placement, patient-reported outcomes, and implant failure rate. METHODS: Electronic databases were searched to identify randomized and non-randomized studies that compared ARP to EIP. The risk of bias was assessed using the Cochrane Collaboration's Risk of Bias tool. Data were analyzed using a statistical software program. RESULTS: A total of 106 studies were identified, of which five studies with 198 non-molar extraction sockets in 198 participants were included. Overall meta-analysis showed significant differences in changes in midfacial mucosal margin (mean difference (MD) -0.09; 95% confidence interval (CI) -0.17 to -0.01; p = .03) and ridge width (MD -1.70; 95% CI -3.19 to -0.20; p = .03) in favor of ARP. The use of ARP was also associated with less need for additional augmentation at implant placement, but the difference was not statistically significant. CONCLUSIONS: Within the limitation of this review, ARP following extraction of non-molar teeth has short-term positive effects on soft tissue contour, mucosal margin and thickness, and alveolar ridge width and height. It can also simplify future implant treatment by minimizing the need for additional augmentation.

Radiographic changes after alveolar ridge preservation using autogenous raw tooth particles versus xenograft: A prospective controlled clinical trial.

OBJECTIVE: The use of extracted teeth has been introduced as an option for bone grafting. However, the current method requires special machines and solutions, posing significant time and cost. The aim of this study was to evaluate the clinical performance of autogenous raw tooth particles (RTP), a grafting material made from a ground tooth using basic equipment, for alveolar ridge preservation. MATERIALS AND METHODS: Twenty-three patients (12 study/11 control), having 14 and 13 sites were included for the study and control groups (commercially available xenograft), respectively. Radiographic measurements were taken at the baseline and the 4-month follow-up appointment. Furthermore, a questionnaire survey concerning the general preference of the type of graft to receive (if needed), before and after knowing the price, was distributed at the completion of the procedure for patients to answer. RESULTS: Alveolar ridge width change was -1.03 ± 0.64 and -0.84 ± 0.35 for the study and the control groups, respectively. Regarding the height, the study group showed a buccal and lingual change of -0.66 ± 0.48 and -0.78 ± 0.81, respectively, while this was -0.78 ± 0.56 and -0.9 ± 0.41 for the xenograft group. There was no statistically significant difference between the groups. Patients preferred the raw tooth particles over other grafting materials (p = .01). CONCLUSION: No core biopsies were taken to evaluate bone formation, which should be done in future studies. Within its limitations, the current study demonstrated that RTP graft could be an alternative graft for bone augmentation, offering a new cost-effective option for clinicians when available.

Osteoradionecrosis incidence in pre-radiation teeth extractions: A prospective study.

AIMS: To evaluate osteoradionecrosis (ORN) incidence in a cohort of patients undergoing tooth extraction (TE) before radiotherapy (RT) for head and neck cancers. METHODS: The study protocol was approved by the Ethics Committee of Università Cattolica del Sacro Cuore (ID-2132) and registered at clinicaltrials.gov (ID: NCT04009161). TE was performed in case of signs of pericoronitis, periapical lesions, restorative impossibility, severe periodontitis. ORN was defined as exposed bone at an unhealed post-extraction socket in the absence of oncological recurrence. The RT plans were reviewed, and each post-extractive socket was contoured to calculate the received radiation dose. RESULTS: In total, 156 patients with 610 TE were enrolled. The mean follow-up was 567 days. ORN was diagnosed in four patients (2.6% of patients and 0.7% of TE). Need for osteotomy and radiation dose at the extraction site were associated with ORN (OR for osteotomy: 21.9, 95% CI: 2.17-222.2, p = 0.009; OR for RT dose: 1.1, 95% CI: 1-1.15, p = 0.05). CONCLUSIONS: TE appears to be a significant risk factor for ORN, particularly when osteotomy is required, and post-extraction sockets receive a high RT dosage. This study proposes a decision-making algorithm for TE and outlines a straightforward surgical protocol.

Efficacy of adjunctive modalities during tooth extraction for the prevention of osteoradionecrosis: A systematic review and meta-analysis.

BACKGROUND: Jaw osteoradionecrosis (ORN) is a complication in patients with previous head and neck radiotherapy. Its incidence increases with dental extractions. Hence, this review aimed to evaluate the efficacy of adjunctive treatment modalities undertaken at the time of extraction in previous head and neck radiotherapy patients in preventing ORN. METHODS: A systematic review was conducted, where studies with data on ORN incidence after extraction with or without adjunctive interventions were included. Meta-analyses were conducted to estimate the pooled prevalence of ORN per intervention and the pooled odds ratio for incidence of ORN between interventions. RESULTS: In total, 1520 patients in 29 studies were included. Interventions identified were hyperbaric oxygen (HBO), pentoxifylline-tocopherol (PENTO), antibiotics (ABX), platelet-rich fibrin and photobiomodulation. The pooled prevalence of ORN for HBO (4.6%), PENTO (3.4%) and ABX (3.8%) was significantly lower than the Control (17.6%). For studies with direct comparisons between groups, HBO had lower but not significant odds of developing ORN than the Control (OR 0.27) and ABX (OR 0.57). CONCLUSIONS: HBO, PENTO and ABX may reduce the incidence of ORN compared to no intervention. Given that all three have similar incidences of ORN, ABX may be the most cost-effective and accessible adjunctive modality.

Protein arginine methyltransferase 5 in osteoblasts promotes the healing of extraction sockets.

OBJECTIVES: To explore the effect of protein arginine methyltransferase 5 (PRMT5) on tooth extraction sockets healing, we established an extraction sockets model in osteoblast-conditional Prmt5 knockout mice. The results provided clues for promoting extraction sockets healing in clinical settings. MATERIALS AND METHODS: Maxillary first molars were extracted from 6 to 8-week-old mice to establish an extraction fossa model. Microcomputed tomography (Micro-CT), histology, and immunostaining assays were performed on samples harvested at 3-, 7-, and 14-day post-extraction. Prmt5-silenced cell lines  were employed to explore the regulatory mechanisms underlying the osteigenic differentiation. RESULTS: PRMT5 expression was higher in the early stage of socket healing. Micro-CT analysis showed that the percentage of new bone in the extraction sockets was lower in OC-Cre; Prmt5fl/fl mice than in the control group, consistent with Masson staining. We found that, Prmt5 deficiency delayed the osteogenesis during extraction socket healing, which might be achieved through the decrease of H4R3me2s in the Sp7 promoter region. CONCLUSION: PRMT5 in osteoblasts may promote the differentiation of osteoblasts by regulating the Sp7 promoter H4R3me2s and participate in the healing of tooth extraction sockets.

Reduction of MRONJ risk after exodontia by virtue of ozone infiltration: A randomized clinical trial.

INTRODUCTION: Exodontia is commonly considered as a risk factor for the development of medication-related osteonecrosis of the jaw (MRONJ) in individuals exposed to bone modifying agents. This study was aimed at assessing the efficiency and safety of a gaseous oxygen-ozone mixture as an adjuvant to a standard exodontia to reduce the risk of MRONJ development. METHODS: A randomized, open-label, phase II, single-center clinical trial involving 117 patients at risk of MRONJ was conducted. The study protocol tested injections of an oxygen-ozone mixture in the post-extraction site. Participants were randomly assigned to two groups: oxygen-ozone therapy, and standard tooth extraction protocol. Post-extraction wound healing was assessed using the Inflammatory Proliferative Remodeling (IPR) Wound Healing Scale. RESULTS: The oxygen-ozone therapy group exhibited a significant improvement in wound healing post-extraction during the inflammatory and proliferative phases, as indicated by the IPR scale scores at 3-5 days (p = 0.006) and 14 days (p < 0.001) respectively. CONCLUSION: Oxygen-ozone therapy shows promise in improving post-extraction healing in patients at risk of MRONJ. Future studies with larger sample sizes and multicenter collaborations are recommended to confirm the validity of these findings and explore the long-term efficacy of ozone therapy.

The impact of the COVID-19 pandemic on 397 631 elective dental admissions among the under-25s in England: a retrospective study.

BACKGROUND: COVID-19 caused widespread disruptions to health services worldwide, including reductions in elective surgery. Tooth extractions are among the most common reasons for elective surgery among children and young people (CYP). It is unclear how COVID-19 affected elective dental surgeries in hospitals over multiple pandemic waves at a national level. METHODS: Elective dental tooth extraction admissions were selected using Hospital Episode Statistics. Admission trends for the first 14 pandemic months were compared with the previous five years and results were stratified by age (under-11s, 11-16s, 17-24s). RESULTS: The most socioeconomically deprived CYP comprised the largest proportion of elective dental tooth extraction admissions. In April 2020, admissions dropped by >95%. In absolute terms, the biggest reduction was in April (11-16s: -1339 admissions, 95% CI -1411 to -1267; 17-24s: -1600, -1678 to -1521) and May 2020 (under-11s: -2857, -2962 to -2752). Admissions differed by socioeconomic deprivation for the under-11s (P < 0.0001), driven by fewer admissions than expected by the most deprived and more by the most affluent during the pandemic. CONCLUSION: Elective tooth extractions dropped most in April 2020, remaining below pre-pandemic levels throughout the study. Despite being the most likely to be admitted, the most deprived under-11s had the largest reductions in admissions relative to other groups.

Why do dentists refrain from intervention in cases of persistent asymptomatic apical periodontitis in root canal filled teeth? An interview study among general dental practitioners.

AIM: To explore the context in which general dental practitioners (GDPs) decide to refrain from further treatment, that is, ortho- or retrograde retreatment or extraction of a root canal filled tooth with persistent asymptomatic apical periodontitis (PAAP). METHODOLOGY: Fifteen GDPs were strategically selected for in-depth interviews. The informants were encouraged to describe in their own words and in as much detail as possible, the three most recent patient cases of PAAP of a root canal filled tooth, in which they decided to refrain from further treatment. The interviews were recorded digitally and transcribed verbatim. The collected material was analysed according to Qualitative Content Analysis with an inductive approach. RESULTS: A pattern of varying degrees of uncertainty associated with the decision process was identified. The motives to refrain intervention had great diversity. The result from analysis of the qualitative data was formulated in an overall theme 'Between doubt and certainty in a complex clinical context' covering the latent content. The first main category covering the manifest content was 'The continuum of confidence' with three subcategories 'Experienced uncertainty', 'Reluctant approval' and 'At ease with refraining' illustrating the feelings and attitudes experienced by the informants. The second category was 'In support of acceptance' with three subcategories 'Patient's autonomy, risks and cost-benefits', 'Emotional aspects' and 'Relieving measures' representing the reasons for refraining from intervention. CONCLUSIONS: The decision to refrain from further treatment, that is, ortho- or retrograde retreatment or extraction of a root canal filled tooth with PAAP was made with some measure of confidence, combined with compensatory strategies to support the decision, taking into account not only values beneficial to the patient and awareness of limited external resources, but also factors related to the informants' personal preferences, convenience, concerns, ambition and emotions.

Effectiveness of preventive intervention programmes aiming to improve oral health in children who have undergone caries-related dental extractions: a rapid review.

OBJECTIVE: To determine the effectiveness of preventive interventions in children who have undergone caries-related dental extractions. METHODS: Rapid review across five databases (CENTRAL, Ovid Medline, Embase, Web of Science and Scopus). Quality was assessed using the Risk of Bias 2 tool. RESULTS: Five studies were included, all randomised controlled trials involving pre-and/or post-extractions activity. Three studies involved oral health education (computer game, motivational interviewing, visual aids), one delivered clinical prevention (fissure sealants), and one an enhanced prevention programme combining additional health education and a clinical intervention (fluoride varnish). Retention was mixed (55%-80% in the intervention groups). Of the three studies measuring caries, all reported less caries development in the test group. However, only a study involving a dental nurse-delivered structured conversation, informed by motivational interviewing, showed an improvement in oral health. Two studies reporting on plaque and gingival bleeding had conflicting results. A study reporting on subsequent dental attendance did not demonstrate a clear improvement. CONCLUSION: Few published studies have explored prevention-based interventions in high caries-risk children requiring dental extractions. Whilst evidence of clinical benefit of preventive interventions in this population is limited, the potential use of contemporary behaviour change techniques appears promising. There is an urgent need for more high-quality longer-term trials using contemporary methodologies.

Longitudinal analysis of microcirculatory parameters in gingival tissues after tooth extraction in patients with different risk profiles for wound healing disorders - a pilot study.

OBJECTIVES: We aimed to establish a risk profile for intraoral wound healing disorders based on measurements of microcirculation in gingival tissues. MATERIALS AND METHODS: Oxygen saturation (SO2) and blood flow in gingival tissues were measured with tissue spectrometry and laser doppler spectroscopy in 37 patients before/after tooth extractions. Patients were assigned to four groups: anamnestically and periodontally healthy patients (n = 7), anamnestically healthy but suffering from periodontitis (n = 10), anamnestically healthy but smoking and suffering from periodontitis (n = 10) and suffering from diabetes and periodontitis (n = 10). Measurements were performed at three different time points: Baseline measurement (T0), one day post extractionem (p.e.) (T1) and seven days p.e. (T2). RESULTS: Baseline SO2 values were higher in control patients (p = .038). This effect was most evident in comparison to smokers suffering from periodontitis (p = .042), followed by diabetics suffering from periodontitis (p = .09). An opposite trend was seen for blood flow. Patients suffering from periodontitis demonstrated higher blood flow values (p = .012). Five patients, which belonged to the group of smokers suffering from periodontitis, showed clinically a delayed wound healing. CONCLUSION: Differences in SO2 and blood flow of gingival tissue could be detected in different groups of patients with existing periodontitis compared to control patients. CLINICAL RELEVANCE: Lower baseline SO2 values could be a warning signal for possible wound healing disorders after oral surgery.

Is the third molar the most frequently extracted tooth? A population-based study utilizing dental panoramic radiographs in adults.

OBJECTIVES: The study aimed to examine the authenticity of the often-mentioned statement that the third molar is the most frequently extracted tooth. This finding has not been shown previously in a large population-based sample. MATERIALS AND METHODS: Data comprised a nationally representative sample of 6082 panoramic radiographs taken from adults in the cross-sectional Health 2000 Survey. From the radiographs, all missing teeth were recorded. Information on congenital agenesis of individual teeth was retrieved from two published meta-analyses. Primary outcome was the frequency of missing teeth by tooth type. Explanatory variables were age, sex, and the jaw (maxilla/mandible). Statistical analyses included χ2 test and binomial logistic regression. RESULTS: Mean age of participants (46% men, 54% women) was 53 years (SD 14.6; range 30‒97 years). Missing teeth occurred more often in women than in men (P < 0.001). The third molar was most frequently missing and the canine least frequently. In the maxilla and mandible, the third molar was missing more often than each of the other tooth types up to the age of 80 years (P < 0.01). CONCLUSIONS: When considering the rates of congenital agenesis of individual teeth, it is concluded that the third molar remained the most common tooth extracted up till the age of 80 years. CLINICAL RELEVANCE: The third molar is the most common target for extraction, but also the most common tooth associated with malpractice claims, and therefore, calls for skills, adequate equipment, and other resources for a successful extraction.