Analysis of risk factors for early crestal bone loss in osseointegrated, submerged implants prior to restoration.

BACKGROUND: Evidence on the etiology behind bone loss around submerged, prosthetically nonloaded implants is still limited. The long-term stability and success of implants with early crestal bone loss (ECBL), especially when placed as two-stage implants, is uncertain. Hence, the aim of this retrospective study is to analyze the potential patient-level, tooth- and implant-related factors for ECBL around osseointegrated, submerged implants, before restoration as compared with healthy implants with no bone loss. METHODS: Retrospective data were collected from patient electronic health records between 2015 and 2022. Control sites included healthy implants with no bone loss and test sites included implants with ECBL, both of which were submerged. Patient, tooth and implant level data were collected. ECBL was assessed using periapical radiographs obtained during implant placement and second-stage surgeries. Generalized estimating equation logistic regression models were used to account for multiple implants within patients. RESULTS: The total number of implants included in the study was 200 from 120 patients. Lack of supportive periodontal therapy (SPT) was shown to have nearly five-times higher risk of developing ECBL and was statistically significant (p < 0.05). Guided bone regeneration (GBR) procedures before implant placement had a protective effect with an odds ratio of 0.29 (p < 0.05). CONCLUSIONS: Lack of SPT was significantly associated with ECBL, while sites that received GBR procedures prior to implant placement were less likely to exhibit ECBL. Our results underscore the importance of periodontal treatment and SPT for peri-implant health, even when the implants are submerged and unrestored.

Translating Clinical Outcomes to Patient Value Through Use of the Periodontal Risk Score: An Evidence-Based Treatment Approach.

Periodontitis is a chronic, multifactorial inflammatory disease characterized by progressive destruction of the tooth-supporting apparatus. Determining tooth prognosis is of central importance in clinical practice to help both the clinician and patient understand the risks and benefits of treatment while shedding light on the patient's long-term periodontal prognosis and aiding in the development of an individualized treatment plan. Several indexing-type systems have been proposed for determining the prognosis of periodontally involved teeth. The periodontal risk score (PRS) is a simple, evidence-based, motivational tool that can be used in daily clinical practice in both healthy and periodontally involved patients. The PRS incorporates systemic and lifestyle prognostic factors to achieve superior predictive accuracy. With the PRS, patients are encouraged to achieve a target score (representing an "excellent" prognosis) that can be realistically attained through compliance with a periodontal maintenance plan. The purpose of this article is to present to clinicians how to implement this evidence-based tool into their daily practices and thus help patients improve their long-term periodontal prognosis.

Periodontal risk score: Initiation and model validation for 6,762 teeth.

BACKGROUND: Tooth-level prognostic systems are valuable tools for treatment planning and risk assessment of periodontally involved teeth. Recently the Miller-McEntire prognosis index was found to outperform comparable systems. However, it had some limitations. The present study aimed to develop and evaluate the prognostic performance of a modified version that addresses most limitations of the previous model called the periodontal risk score (PRS). METHODS: Data were retrieved retrospectively from patients who received surgical and non-surgical periodontal treatment at a university setting. Data on medical history and smoking status at baseline and the last maintenance visit were collected. Both univariate and multivariate Cox proportional hazard regression models were used to analyze the prognostic capability for predicting tooth loss due to periodontitis (TLP) risk. RESULTS: A total of 6762 teeth (281 patients) were followed up for a mean period of 22.6 ± 6.34 (10-47.6y) years. The PRS was successfully able to stratify the risk of TLP at baseline when the three different classes of association were compared for anterior and/or posterior tooth loss. After controlling for maintenance, age, and sex, the index showed an excellent predictive capacity for TLP with a Harrell C-index of 0.947. CONCLUSIONS: The periodontal risk score (PRS) displayed excellent predictive capability for anterior as well as posterior tooth loss due to periodontitis. This system was able to predict long-term tooth loss with a very high accuracy  in a population treated mainly by dental students and periodontics residents. The use of this/similar prognosis system is advisable as a means to establish tooth prognosis.

Flap versus flapless alveolar ridge preservation: A clinical and histological single-blinded, randomized controlled trial.

BACKGROUND: The aim of this randomized clinical trial was to compare a flapless technique of alveolar ridge preservation (ARP) to a flap technique to determine if preserving the periosteal blood supply would limit loss of crestal ridge width and height. METHODS: Twenty-four patients were randomly assigned to receive ARP using either a flapless or flap technique. Sockets were grafted with demineralized bone matrix and mineralized particulate allograft then covered with a barrier in both groups. Re-entry was performed at 4 months to obtain samples for histological analysis and subsequent implant placement. RESULTS: Ridge width of the flapless group at the crest decreased from 8.3 ± 1.3 mm to 7.0 ± 1.9 mm for a mean loss of 1.3 ± 0.9 mm (p < 0.05), whereas the flap group decreased from 8.5 ± 1.5 mm to 7.5 ± 1.5 mm for a mean loss of 1.0 ± 1.1 mm (p < 0.05). The mean midbuccal vertical change for the flap group was a loss of 0.9 ± 1.3 mm (p < 0.05) versus 0.5 ± 0.9 mm (p < 0.05) for the flapless group. There was no statistically significant difference between the groups. Histologically, flapless ARP revealed more vital mineralized tissue (44 ± 10%) compared to the flap group (p>0.05). In the flapless group, the occlusal soft tissue was significantly thicker than in the flap group at the 4-month re-entry (p< 0.05). CONCLUSIONS: Crestal ridge width, height, and percentage of vital mineralized bone following treatment with a flapless ARP technique, was not significantly different from a flap technique.

Is the degree of physiological bone remodeling a predictive factor for peri-implantitis?

BACKGROUND: The amount of initial physiological bone remodeling (IPBR) after implant placement varies and the ways it may play a role in peri-implantitis development remains unknown. The aim of this retrospective study was to investigate the association between the amount of IPBR during the first year of implant placement and incidence of peri-implantitis as well as the pattern of progressive bone loss. METHODS: Clinical and radiographic documentation of implants at the time of implant placement (T0), 1 year ± 6 months after crown placement (T1), and at a ≥2-year follow-up from implant placement (T2) were retrospectively collected. IPBR was defined as the bone loss occurring from implant placement to the end of the bone remodeling (T1). Cases were grouped into those diagnosed with (test) or without peri-implantitis (PIm) (control). Linear regression model under generalized estimation equation approach was estimated to assess correlation between marginal bone loss (MBL) rates in both periods (T1-T0) and (T2-T1). Receiver operating characteristics curve was estimated to explore an optimal cut-off point of T1-T0 MBL to discriminate between PIm and no-PIm implants. RESULTS: A total of 45 patients receiving 57 implants without PIm and 40 with PIm were included. There were no associations between PIm and IPBR (p > 0.05), nor between BML of (T2-T1) and (T1-T0). However, arch and total follow-up showed significant influence on the probability of PIm. Splinted implants showed an MBL rate of 0.60-mm/year higher than non-splinted implants (p < 0.001) from T1 to T2. CONCLUSION: No statistically significant association was found between IPBR and incidence of peri-implantitis.

Impact of the periodontal phenotype in premolar and molar sites on bone loss following full-thickness mucoperiosteal flap: A 1-year prospective clinical trial.

BACKGROUND: Full-thickness mucoperiosteal flap (FTF) elevation could potentially affect the periodontium of the involved teeth; it is not clear if the periodontal phenotype of teeth involved in a FTF may influence these changes. The aim of this study was to evaluate the impact of FTF on teeth periodontium, as well as assessing the impact of periodontal phenotype on bone remodeling. METHODS: In this single arm prospective clinical trial, 26 subjects and a total of 52 adjacent teeth were included. Patients receiving implant surgery in the posterior area, at the time of implant site preparation, an FTF was extended one tooth mesial and distal to the planned site, and the flap was elevated both facially and lingually. Vertical and horizontal bone linear changes were measured on both adjacent teeth, using superimposed cone-beam computerized tomography (CBCT) images taken prior to implant placement (T0) and at 12 months (T1). Baseline digital scans of models and DICOM files were superimposed to assess the periodontal phenotype. RESULTS: Vertical bone changes from T0 to T1 were statistically significant (P = 0.013), with changes were significantly higher at the mesial (-0.31 ± 0.30 mm) and facial (P < 0.05) sites. Horizontal dimensional changes 5 mm subcrestally were similar among different locations (P = 0.086) and the bone width loss was higher closest to the crest (P = 0.001). No correlation was found between soft tissue thickness and bone changes. However, bone thickness at baseline appears to influence the extent of horizontal bone remodeling. Overall, the magnitude of bone loss either vertically or horizontally was clinically insignificant (≤0.4 mm). A preventive effect against bone loss maybe expected with bone thickness > 2 mm. CONCLUSION(S): Marginal bone changes in maxillary and mandibular posterior teeth following FTF at 12 months are very minimal, and mainly influenced by bone rather than soft tissue thickness. Overall, FTF does not seem to have deleterious effects on adjacent teeth periodontium.

Long term comparison of the prognostic performance of PerioRisk, periodontal risk assessment, periodontal risk calculator, and staging and grading systems.

BACKGROUND: Clinicians predominantly use personal judgment for risk assessment. Periodontal risk assessment tools (PRATs) provide an effective and logical system to stratify patients based on their individual treatment needs. This retrospective longitudinal study aimed to validate the association of different risk categories of four PRATs (Staging and grading; Periodontal Risk Assessment (PRA); Periodontal Risk Calculator; and PerioRisk) with periodontal related tooth loss (TLP), and to compare their prognostic performance. METHODS: Data on medical history, smoking status, and clinical periodontal parameters were retrieved from patients who received surgical and non-surgical periodontal treatment. A comparison of the rate of TLP and non-periodontal related tooth loss (TLO) within the risk tool classes were performed by means of Kruskal-Wallis test followed by post-hoc comparison with the Bonferroni test. Both univariate and multivariate Cox Proportional hazard regression models were built to analyze the prognostic significance for each single risk assessment tool class on TLP. RESULTS: A total of 167 patients with 4321 teeth followed up for a mean period of 26 years were assigned to four PRATs. PerioRisk class 5 had a hazard ratio of 18.43, Stage 4 had a hazard ratio of 7.99, and PRA class 3 had a hazard ratio of 6.13 compared with class/stage I. With respect to prognostic performance, PerioRisk tool demonstrated the best discrimination and model fit followed by PRA. CONCLUSION: All PRATs displayed very good predictive capability of TLP. PerioRisk showed the best discrimination and model fit, followed by PRA.

Prognostic performance of the 2017 World Workshop classification on staging and grading of periodontitis compared with the British Society of Periodontology's implementation.

BACKGROUND: The British Society of Periodontology (BSP) implemented a simplified version of the 2017 World Workshop Classification (WWC) on staging and grading of periodontitis, for use in UK clinical practice. The aim of this study was to assess the long-term (>10 years) prognostic capability of BSP's implementation (BSP-i) compared with the 2017 WWC, using periodontal-related tooth loss (TLP) as a disease outcome. METHODS: Data on medical history, smoking status, and clinical periodontal parameters were retrieved from 270 patients who received non-surgical and surgical periodontal therapy from 1966 to 2007. Each patient received a baseline diagnosis according to the 2017 WWC and the BSP-i guidelines for implementation. Univariate multilevel Cox regression frailty models were performed to analyze the association between variables with TLP. A post-hoc comparison with Bonferroni correction was performed to analyze interclass comparisons. The prognostic performance of both systems was analyzed using Harrell C index. RESULTS: The prognostic performance of both systems was very similar (0.922 for the 2017 WWC and 0.925 for the BSP-i). The singular prognostic performance of BSP stage was slightly higher than that of 2017 WWC stage (0.9212 versus 0.9188), while the 2017 WWC grade showed a slightly better performance than BSP grade (0.9175 versus 0.9155). BSP-i's extent performed better than the 2017 WWC extent (0.9203 versus 0.9098); however, in the 2017 WWC extent, the class "localized" was associated with a better prognosis than "generalized." CONCLUSION: The overall prognostic performance of the two systems was excellent, with both systems having a Harrell C index score of >0.92.

Microbiome-mediated incapacitation of interferon lambda production in the oral mucosa.

Here, we show that Porphyromonas gingivalis (Pg), an endogenous oral pathogen, dampens all aspects of interferon (IFN) signaling in a manner that is strikingly similar to IFN suppression employed by multiple viral pathogens. Pg suppressed IFN production by down-regulating several IFN regulatory factors (IRFs 1, 3, 7, and 9), proteolytically degrading STAT1 and suppressing the nuclear translocation of the ISGF3 complex, resulting in profound and systemic repression of multiple interferon-stimulated genes. Pg-induced IFN paralysis was not limited to murine models but was also observed in the oral tissues of human periodontal disease patients, where overabundance of Pg correlated with suppressed IFN generation. Mechanistically, multiple virulence factors and secreted proteases produced by Pg transcriptionally suppressed IFN promoters and also cleaved IFN receptors, making cells refractory to exogenous IFN and inducing a state of broad IFN paralysis. Thus, our data show a bacterial pathogen with equivalence to viruses in the down-regulation of host IFN signaling.

External validation and comparison of the predictive performance of 10 different tooth-level prognostic systems.

AIM: Tooth-level prognostic systems can be used for treatment planning and risk assessment. This retrospective longitudinal study aimed to evaluate the prognostic performance of 10 different tooth-level risk assessment systems in terms of their ability to predict periodontal-related tooth loss (TLP). MATERIALS AND METHODS: Data were retrieved retrospectively from patients who received surgical and non-surgical periodontal treatment. Data on medical history and smoking status at baseline and the last maintenance visit were collected. Ten tooth-level prognostic systems were compared using both univariate and multivariate Cox proportional hazard regression models to analyse the prognostic capability of each system for predicting TLP risk. RESULTS: One-hundred and forty-eight patients with 3787 teeth, followed-up for a mean period of 26.5 ± 7.4 years, were evaluated according to 10 different tooth-level prognostic systems, making up a total of 37,870 individual measurements. All compared prognostic systems were able to stratify the risk of TLP at baseline when different classes of association were compared. After controlling for maintenance, age, and gender, all systems exhibited excellent predictive capacity for TLP with no system scoring a Harrell's C-index less than 0.925. CONCLUSIONS: All tooth-level prognostic systems displayed excellent predictive capability for TLP. Overall, the Miller and McEntire system may have shown the best discrimination and model fit, followed by the Nunn et al. system.

Occupational percutaneous injuries and exposures in a dental teaching environment: A 10-year report.

PURPOSE: Percutaneous injuries (PIs) are woefully underreported and the risk at dental academic institutions is higher due to lack of knowledge and experience of students. The aims of this study are to (1) present data on the prevalence of PIs and exposures over a 10-year period in a dental teaching institution; (2) provide information on areas with increased risk as it relates to personnel and instruments; and (3) improve the awareness of the risk of occupational PIs and exposures in dentistry. METHODS: Data presented were collected as a part of an infection control program. A description of the incident reporting and collecting methodology is provided. Distribution tables and confidence intervals for injuries by year were calculated. Overall associations were produced using either Fisher's exact or Chi-square test. RESULTS: Between 2009 and 2019, a total of 342 PIs (338) and mucosal exposures (4) were reported. A significant number of injuries occurred while reaching for an instrument (15.2%), injecting local anesthetic (13.2%), and cleaning an instrument (11.7%). About 31% of the injuries were caused by needlesticks followed by burs (22.8%). There was a statistically significant association between work practice controls and activity type (p < 0.001) and position (p = 0.01). PIs and compliance issues were higher among the third-year dental students. CONCLUSIONS: There was a declining trend in incidents over the years, which could be attributed to the extra-protective measures that were implemented. Uncovered dental burs and needlesticks continue to be the predominant cause of PIs in academia. We found that collection of data on such occupation-related injuries to be useful in observing any trends and implementation of corrective actions.

Is bleeding on probing a reliable clinical indicator of peri-implant diseases?

Bleeding on probing (BOP) is regarded as an indispensable diagnostic tool for evaluating periodontal disease activity; however, its role in peri-implant disease is more intricate. Much of the confusion about the interpretation originates from drawing parallels between periodontal and peri-implant conditions. BOP can originate from two forms of probing in implants: traumatic or pathologic induction. This, in addition to the dichotomous scale of BOP can complicate diagnosis. The objective of this commentary is to discuss the following: 1) the value of BOP as a diagnostic tool for peri-implant diseases; 2) the reasons it should be distinct from value for diagnosing periodontal and peri-implant diseases; and 3) the current best evidence on how to implement it in daily clinical practice. A comprehensive bleeding index is proposed for evaluating and monitoring peri-implant conditions. BOP should be used in addition to other parameters such as visual signs of inflammation, probing depth, and progressive bone loss before a peri-implant diagnosis is established.