Predictors of standardized in-service examination performance and residency outcomes in a graduate periodontics program

PURPOSE/OBJECTIVES

The objectives of this study were to assess the influence of learner- and education-related factors on standardized in-service examination performance and determine whether in-service examination scores predict residency outcomes.

METHODS

American Academy of Periodontology (AAP) In-service Examination (AIE) scores from 10 periodontics residency classes at a single center were recorded and compared against a panel of learner- and education-related variables using multiple linear regression models. Defined residency outcome measures were analyzed against AIE scores using binomial logistic regression.

RESULTS

No evaluated learner- or education-related variable was a statistically significant predictor of AIE score in this study sample. Likewise, AIE score was not a statistically significant predictor of any assessed residency outcome.

CONCLUSIONS

The AAP has performed a tremendous service to periodontics residents and programs by marshaling the leadership and expertise necessary to offer a professionally constructed assessment instrument. However, in the current study, no relationship could be identified between AIE score and any outcome, including first-attempt board certification. The AAP In-service Committee appears well situated to provide additional leadership focusing on exam implementation, which may enhance AIE value in competency decision making.

Protocol for ridge preservation at severely compromised extraction sockets: Consecutive case series

BACKGROUND

The physiologic bone remodeling accompanying tooth extraction is a phenomenon well described in the dental literature. Extraction sockets severely compromised by local infection, trauma, iatrogenesis, or other factors may exhibit enhanced reduction in alveolar dimensions during healing. The purpose of this report is to present an alveolar ridge preservation (ARP) protocol specifically intended for use at severely compromised sites.

METHODS

Seven patients presented to the Department of Periodontics, Army Postgraduate Dental School, Fort Gordon, Georgia, requiring extraction of teeth with partial or near-complete loss of the facial/buccal cortex. At each site, a cross-linked bovine collagen membrane was used to prevent collapse of the facial/buccal soft tissue and maintain space, a freeze-dried bone allograft was applied in the socket, and a dense polytetrafluoroethylene membrane covered the occlusal aspect.

RESULTS

All sites healed uneventfully and resulted in favorable alveolar ridge dimensions for implant placement.

CONCLUSION

Few authors have proposed specific ARP methods for managing severely deficient extraction sockets. The predominant recommendation has been staged reconstruction of the site applying hard and soft tissue augmentation. Observations reported herein suggest that staged reconstruction is avoidable at some extraction sockets exhibiting severe alveolar compromise. Controlled clinical investigation of this protocol appears warranted.

KEY POINTS

Few authors have proposed alveolar ridge preservation (ARP) methods specifically intended for use at severely compromised extraction sockets. The prevailing recommendation at such sites is a staged protocol involving tooth extraction with delayed hard and soft tissue augmentation. The presented bilaminar ARP technique may eliminate the need for staged reconstruction at some severely compromised extraction sockets.

Factors influencing intraoperative and postoperative complication occurrence: A series of 1135 periodontal and implant-related surgeries

OBJECTIVES

In periodontology, it is widely recognized that evidence characterizing the incidence and effect of treatment complications is lacking. The objective of this study was to assess the influence of operator-, procedure-, patient-, and site-associated factors on intraoperative and postoperative complication occurrence.

MATERIAL AND METHODS

A single investigator reviewed records of patients treated by eight periodontics residents from July 2018 through June 2022. For each procedure, the investigator recorded each intraoperative and postoperative complication or indicated that no complication had occurred. These outcomes were analyzed against a panel of explanatory covariates. In addition, the severity of each postoperative complication was assessed using a standardized grading system.

RESULTS

A total of 1135 procedures were included in the analysis. Intraoperative and postoperative complications were identified in 2.8% and 15.2% of procedures, respectively. The most common intraoperative complications were Schneiderian membrane perforation (1.3%) and gingival flap perforation/tear (1%), and the most common postoperative complications were dentin hypersensitivity (2.6%), excessive pain (2.5%), and infection (2.2%). Subepithelial connective tissue graft (odds ratio [OR]: 3.2, 95% confidence interval [CI]: 1.6, 6.1; p < .001), guided bone regeneration (OR: 3.0, 95% CI: 1.4, 6.5; p = .004), and guided bone regeneration with implant placement (OR: 3.1, 95% CI: 1.3, 7.6; p = .011) were associated with higher odds of postoperative complication, whereas lateral sinus elevation (OR: 102.5, 95% CI: 12.3, 852.9; p < .001), transalveolar sinus elevation (OR: 22.4, 95% CI: 2.2, 224.5; p = .008), open flap debridement (OR: 36.4, 95% CI: 3.0, 440.7; p = .005), and surgically facilitated orthodontic therapy (OR: 20.5, 95% CI: 1.2, 358.4; p = .039) were associated with higher odds of intraoperative complication occurrence.

CONCLUSIONS

Consistent with previous reports, procedure type appears to be the predominant factor driving complication occurrence. As analyses of treatment complications increase, individualized risk-benefit assessments will become progressively meaningful for patients.

Experimental Evidence of Plasmoids in High-β Magnetic Reconnection

Magnetic reconnection is a ubiquitous and fundamental process in plasmas by which magnetic fields change their topology and release magnetic energy. Despite decades of research, the physics governing the reconnection process in many parameter regimes remains controversial. Contemporary reconnection theories predict that long, narrow current sheets are susceptible to the tearing instability and split into isolated magnetic islands (or plasmoids), resulting in an enhanced reconnection rate. While several experimental observations of plasmoids in the regime of low-to-intermediate β (where β is the ratio of plasma thermal pressure to magnetic pressure) have been made, there is a relative lack of experimental evidence for plasmoids in the high-β reconnection environments which are typical in many space and astrophysical contexts. Here, we report strong experimental evidence for plasmoid formation in laser-driven high-β reconnection experiments.

Guided protocol for indirect fabrication of a custom provisional restoration prior to immediate implant surgery in the esthetic zone

BACKGROUND

Delivery of a high-quality provisional restoration at a maxillary anterior immediate implant site enhances patient-centered outcomes and promotes development of favorable hard and soft tissue architecture. The purpose of this report is to present a protocol relying upon compatible guided surgery and laboratory systems for fabrication of a custom provisional crown prior to immediate implant surgery in the esthetic zone.

METHODS AND RESULTS

A female patient, aged 33 years, presented to the Army Postgraduate Dental School, Fort Gordon, Georgia, with an unfavorable prognosis for tooth #9. The patient elected extraction with immediate implant placement. Prior to the surgery, we utilized a cone-beam computed tomography volume, stone models, implant planning software, and an implant indexing system to fabricate a custom provisional crown. Following extraction of tooth #9 and immediate implant placement, the provisional crown exhibited excellent fit and finish, requiring virtually no chairside adjustment. We noted minimal change in baseline mucosal contours throughout the healing phase.

CONCLUSION

The clinical/restorative protocol described in this report assured accurate three-dimensional implant positioning and permitted indirect fabrication of a high-quality custom provisional crown in advance of surgery. The laboratory workflow-which dental technicians/auxiliaries can master-has the potential to shorten surgery, enhance treatment outcomes, and increase patient satisfaction.

KEY POINTS

Why is this case new information? This report provides a stepwise workflow guiding indirect fabrication of a custom provisional crown prior to immediate implant placement. What are the keys to successful management of this case? The described technique requires compatible laboratory and guided surgery systems to assure that the restoration accounts for the three-dimensional position and timing of the implant. What are the primary limitations to success in this case? Dental technicians/auxiliaries can master this protocol and independently produce high-quality provisional implant restorations under supervision, potentially enhancing practice efficiency. However, practitioners should provide adequate staff training to optimize reliability and quality.

Clinical protocol selection for alveolar ridge augmentation at sites exhibiting slight, moderate, and severe horizontal ridge deficiencies

FOCUSED CLINICAL QUESTION

What factors identify the optimal bone augmentation techniques for managing slight, moderate, and severe horizontal alveolar ridge deficiency (ARD) at dental implant sites?

SUMMARY

Horizontal ARD is a concern at a high proportion of sites receiving dental implants, and clinicians have developed a variety of surgical procedures to address such defects. In a particular case, selection of the optimal treatment may depend predominantly on defect severity, location (anterior versus posterior), and configuration (contained versus noncontained). This report provides a framework for selecting an augmentation method when presented with a slight, moderate, or severe horizontal ARD at a site requiring dental implant placement.

CONCLUSION

Multiple treatment options are available for planned implant sites exhibiting horizontal ARD; severe posterior and slight anterior defects intuitively call for different approaches. Although rigid guidelines for selecting the optimal augmentation method do not exist, some techniques are poorly suited for esthetically demanding sites. A framework considering defect severity, location, and configuration may help guide clinical decisions on this topic.

Double Spike-Standard Addition Technique and Its Application in Measuring Isotopes

Double spike (DS) method has been extensively used in determining stable isotope ratios of many elements. However, challenges remain in obtaining high-precision isotope data for ultra-trace elements owing to the limitations of instrumental signal-to-noise ratios and the systematics of precision of DS-based measurements. Here, the DS-standard addition (SA) (DSSA) technique is proposed to improve measurements of isotope compositions of ultra-trace elements in natural samples. According to the U-shaped relationship between DS measurement uncertainty and the spike/sample ratio, theoretical equations and an error propagation model (EPM) were constructed comprehensively. In our method, a spiked secondary standard solution with a high, precisely known spike/sample ratio is mixed with samples such that the mixtures have spike/sample ratios within the optimal range. The abundances of the samples relative to the added standards (sample fraction; f_spl) and the samples' isotope ratios can then be obtained exactly using a standard DS data reduction routine and the isotope binary mixing model. The accuracy and precision of the DSSA approach were verified by measurements of cadmium and molybdenum isotopes at as low as 5 ng levels. Compared with traditional DS measurements, the sample size for isotope analysis is reduced to 1/6-1/5 of the original with no loss of measurement precision. The optimal mixing range f_spl = 0.15-0.5 is recommended. The DSSA method can be extended to isotope measurement of more than 33 elements where the DS method is applicable, especially for the ultra-trace elements such as platinum group and rare earth element isotopes.

Influence of Lactobacillus reuteri, Bifidobacterium animalis subsp. lactis, and prebiotic inulin on dysbiotic dental biofilm composition ex vivo

BACKGROUND

Probiotic bacterial supplementation has shown promising results in the treatment of periodontitis and the maintenance of periodontal health. The purpose of this investigation was to evaluate the influence of Lactobacillus reuteri or Bifidobacterium animalis subsp. lactis supplementation with and without prebiotic inulin on biofilm composition using an ex vivo biofilm model.

METHODS

Subgingival plaque specimens from three periodontitis-affected human donors were used to grow biofilms on hydroxyapatite disks in media supplemented with varying combinations of prebiotic inulin, Lactobacillus reuteri, and Bifidobacterium animalis subsp. lactis. Relative abundances of bacterial genera present in mature biofilms were evaluated using 16S rRNA next-generation sequencing. Diversity metrics of microbial communities were evaluated using a next-generation microbiome bioinformatics platform.

RESULTS

Inulin supplementation produced statistically significant dose-dependent increases in relative abundances of Lactobacillus and Bifidobacterium species (p < 0.001) with concomitant decreases in relative abundances of Streptococcus, Veillonella, Fusobacterium, Parvimonas, and Prevotella species (p < 0.001). Inoculation with L. reuteri or B. animalis subsp. lactis increased the relative abundance of only the supplemented probiotic genera (p < 0.05). Supplemental inulin led to a statistically significant decrease in biofilm alpha diversity (p < 0.001).

CONCLUSIONS

The described ex vivo model appears suitable for investigating the effects of probiotic bacteria, prebiotic oligosaccharides, and combinations thereof on biofilm composition and complexity. Within the limitations imposed by this model, results from the present study underscore the potential for prebiotic inulin to modify biofilm composition favorably. Additional research further elucidating biologic rationale and controlled clinical research defining therapeutic benefits is warranted.

In situ calibration of charged particle spectrometers on the OMEGA Laser Facility using 241Am and 226Ra sources

Charged particle spectrometry is a critical diagnostic to study inertial-confinement-fusion plasmas and high energy density plasmas. The OMEGA Laser Facility has two fixed magnetic charged particle spectrometers (CPSs) to measure MeV-ions. In situ calibration of these spectrometers was carried out using ²⁴¹Am and ²²⁶Ra alpha emitters. The alpha emission spectrum from the sources was measured independently using surface-barrier detectors (SBDs). The energy dispersion and broadening of the CPS systems were determined by comparing the CPS measured alpha spectrum to that of the SBD. The calibration method significantly constrains the energy dispersion, which was previously obtained through the measurement of charged particle fusion products. Overall, a small shift of 100 keV was observed between previous and the calibration done in this work.

Phased plan for the implementation of the time-resolving magnetic recoil spectrometer on the National Ignition Facility (NIF)

The time-resolving magnetic recoil spectrometer (MRSt) is a transformative diagnostic that will be used to measure the time-resolved neutron spectrum from an inertial confinement fusion implosion at the National Ignition Facility (NIF). It uses a CD foil on the outside of the hohlraum to convert fusion neutrons to recoil deuterons. An ion-optical system positioned outside the NIF target chamber energy-disperses and focuses forward-scattered deuterons. A pulse-dilation drift tube (PDDT) subsequently dilates, un-skews, and detects the signal. While the foil and ion-optical system have been designed, the PDDT requires more development before it can be implemented. Therefore, a phased plan is presented that first uses the foil and ion-optical systems with detectors that can be implemented immediately-namely CR-39 and hDISC streak cameras. These detectors will allow the MRSt to be commissioned in an intermediate stage and begin collecting data on a reduced timescale, while the PDDT is developed in parallel. A CR-39 detector will be used in phase 1 for the measurement of the time-integrated neutron spectra with excellent energy-resolution, necessary for the energy calibration of the system. Streak cameras will be used in phase 2 for measurement of the time-resolved spectrum with limited spectral coverage, which is sufficient to diagnose the time-resolved ion temperature. Simulations are presented that predict the performance of the streak camera detector, indicating that it will achieve excellent burn history measurements at current yields, and good time-resolved ion-temperature measurements at yields above 3 × 10¹⁷. The PDDT will be used for optimal efficiency and resolution in phase 3.

High-yield magnetic recoil neutron spectrometer on the National Ignition Facility for operation up to 60 MJ

Recent progress at the National Ignition Facility (NIF), with neutron yields of order 1 × 10¹⁷, places new constraints on diagnostics used to characterize implosion performance. The Magnetic Recoil neutron Spectrometer (MRS), which is routinely used to measure yield, ion temperature (T_ion), and down-scatter ratio (dsr), has been adapted to allow measurements of dsr up to 5 × 10¹⁷, and yield and T_ion up to 2 × 10¹⁸ in the near term with new data processing techniques and conversion foil solutions. This paper presents a solution for extending MRS operation up to a yield of 2 × 10¹⁹ (60 MJ) by moving the spectrometer outside of the NIF shield wall. This will not only enhance the upper yield limit by 10× but also improve signal-to-background by 5×.

Experiments on the dynamics and scaling of spontaneous-magnetic-field saturation in laser-produced plasmas

In laser-produced high-energy-density plasmas, large-scale strong magnetic fields are spontaneously generated by the Biermann battery effects when temperature and density gradients are misaligned. Saturation of the magnetic field takes place when convection and dissipation balance field generation. While theoretical and numerical modeling provide useful insight into the saturation mechanisms, experimental demonstration remains elusive. In this letter, we report an experiment on the saturation dynamics and scaling of Biermann battery magnetic field in the regime where plasma convection dominates. With time-gated charged-particle radiography and time-resolved Thomson scattering, the field structure and evolution as well as corresponding plasma conditions are measured. In these conditions, the spatially resolved magnetic fields are reconstructed, leading to a picture of field saturation with a scaling of B∼1/L_{T} for a convectively dominated plasma, a regime where the temperature gradient scale (L_{T}) exceeds the ion skin depth.

Implant site development requirements in an advanced dental education program: A series of 290 implants

PURPOSE

Our purpose was to assess the frequency and impact of various site development procedures provided before, during, and after implant placement in an advanced dental education program.

METHODS

We evaluated all implant cases completed by two residents in each of three consecutive periodontics residency classes. Dependent variables included implant failure, complication occurrence, presence of radiographic bone loss, and need for tissue augmentation. We analyzed these outcomes against a panel of explanatory covariates.

RESULTS

Our study sample involved 370 site development procedures at 290 implant sites in 160 patients. Three factors exhibited statistically significant associations with need for tissue augmentation: alveolar ridge preservation (ARP) (odds ratio [OR] 0.28; 95% confidence interval [CI] 0.13, 0.57), immediate implant placement (IIP) (OR 0.21; 95% CI 0.10, 0.47), and implant submergence (OR 8.3; 95% CI 4.5, 15.3). Four factors predicted treatment complications: ARP (OR 6.1; 95% CI 1.3, 29.1), IIP (OR 6.1; 95% CI 1.06, 35.3), implant submergence (OR 5.3; 95% CI 1.1, 24.9), and mandibular arch (OR 31.3; 95% CI 1.9, 500). Anterior sites (OR 2.7; 95% CI 1.3, 5.8) were more likely to receive IIP.

CONCLUSIONS

In the evaluated sample, implant placement at a site exhibiting a favorable volume of native bone was rare. Seventy-eight percent of sites received hard tissue grafting during the treatment phase. The use of ARP or IIP at tooth extraction reduced subsequent tissue augmentation requirements. Education and training in ARP and other site development procedures may enhance the clinical practice and treatment outcomes of implant surgeons.

Exploratory evaluation of baseline cognition as a predictor of perceived benefit in a study of behavioral therapy for urinary incontinence in Parkinson disease

AIMS

While behavior-based pelvic floor muscle exercise therapy is an effective treatment for overactive bladder in Parkinson's disease (PD) patients, cognitive function may be a predictor of rehabilitation outcomes.

METHODS

In a planned exploratory analysis, participants who had a Montreal Cognitive Assessment (MoCA) with a score ≥18 who were randomized in a clinical trial to behavioral treatment were classified by perceived improvement (Benefit vs. No Benefit) as reported on a validated Satisfaction and Benefit Questionnaire. General cognition (MoCA), motor procedural learning (Serial reaction time task), verbal memory (Buschke delayed recall), spatial memory (Nonverbal/Spatial selective reminding test), and working memory (Wisconsin card sorting task) were compared between the two groups using Wilcoxon rank-sum test.

RESULTS

Of the 26 participants randomized to behavioral treatment (70% male, mean age 71 ± 6.1 years), 22 participants (85%) reported Benefit and four reported No Benefit. General cognition, motor procedural learning, verbal memory, spatial memory, and working memory did not differ between these groups. While the difference between the time to complete the final practiced series and the random series of the Serial Reaction Time Task (SRTT) was statistically similar between the groups, the Benefit group performed the random sequence more quickly (567.0 ± 136.5 ms) compared to the No Benefit group (959.4 ± 443.0 ms; p = 0.03) and trended toward faster performance in the final practiced series.

CONCLUSIONS

Perceived benefit from behavioral treatment for overactive bladder was not associated with measures of baseline cognition other than faster completion of the SRTT. This is noteworthy because many behavior-based therapy studies exclude participants with mild cognitive impairment. Additional studies may evaluate if domain-specific cognitive function, particularly the assessment of implicit memory, could lead to individualized behavioral therapy recommendations.

A critical review on the occurrence and distribution of the uranium- and thorium-decay nuclides and their effect on the quality of groundwater

This critical review presents the key factors that control the occurrence of natural elements from the uranium- and thorium-decay series, also known as naturally occurring radioactive materials (NORM), including uranium, radium, radon, lead, polonium, and their isotopes in groundwater resources. Given their toxicity and radiation, elevated levels of these nuclides in drinking water pose human health risks, and therefore understanding the occurrence, sources, and factors that control the mobilization of these nuclides from aquifer rocks is critical for better groundwater management and human health protection. The concentrations of these nuclides in groundwater are a function of the groundwater residence time relative to the decay rates of the nuclides, as well as the net balance between nuclides mobilization (dissolution, desorption, recoil) and retention (adsorption, precipitation). This paper explores the factors that control this balance, including the relationships between the elemental chemistry (e.g., solubility and speciation), lithological and hydrogeological factors, groundwater geochemistry (e.g., redox state, pH, ionic strength, ion-pairs availability), and their combined effects and interactions. The various chemical properties of each of the nuclides results in different likelihoods for co-occurrence. For example, the primordial ²³⁸U, ²²²Rn, and, in cases of high colloid concentrations also ²¹⁰Po, are all more likely to be found in oxic groundwater. In contrast, in reducing aquifers, Ra nuclides, ²¹⁰Pb, and in absence of high colloid concentrations, ²¹⁰Po, are more mobile and frequently occur in groundwater. In highly permeable sandstone aquifers that lack sufficient adsorption sites, Ra is often enriched, even in low salinity and oxic groundwater. This paper also highlights the isotope distributions, including those of relatively long-lived nuclides (²³⁸U/²³⁵U) with abundances that depend on geochemical conditions (e.g., fractionation induced from redox processes), as well as shorter-lived nuclides (²³⁴U/²³⁸U, ²²⁸Ra/²²⁶Ra, ²²⁴Ra/²²⁸Ra, ²¹⁰Pb/²²²Rn, ²¹⁰Po/²¹⁰Pb) that are strongly influenced by physical (recoil), lithological, and geochemical factors. Special attention is paid in evaluating the ability to use these isotope variations to elucidate the sources of these nuclides in groundwater, mechanisms of their mobilization from the rock matrix (e.g., recoil, ion-exchange), and retention into secondary mineral phases and ion-exchange sites.

Dental implants at sites of focal high and mixed density osseous lesions: Clinical practice guidelines

FOCUSED CLINICAL QUESTION

Under what circumstances may a clinician consider dental implant placement at a site exhibiting a focal high or mixed density (HMD) osseous lesion radiologically?

SUMMARY

Some conditions and pathologic entities exhibiting high and mixed density radiological appearance pose low risk for dental implant failure or complications following implant surgery. However, other lesions represent contraindications to implant placement, and implant surgery at such sites can result in severe morbidity.

CONCLUSION

Potential implant sites exhibiting focal HMD osseous lesions/conditions present varying levels of risk. In most cases, optimal management will include advanced imaging of the site, multidisciplinary consultations, and detailed informed consent to assure full understanding of procedural risks, benefits, and complications. Currently, clinical recommendations rely on case reports, opinion, and usual practice (level 3 evidence). The strength of each recommendation provided in this report is categorized as level C.

The Triangle Suture for Membrane Fixation in Guided Bone Regeneration Procedures: A Report of two Cases

INTRODUCTION

Existing evidence supports superior treatment outcomes in guided bone regeneration (GBR) procedures employing membrane fixation. The purpose of this report is to present a specific flap design and suturing method for stabilizing GBR barrier membranes.

CASE PRESENTATION

Two generally healthy patients received GBR using native collagen membranes stabilized with absorbable sutures. In both cases, we fixed barrier membranes apically using "triangle" sutures. Sling sutures (Case 1) or triangle sutures (Case 2) secured the crestal and palatal aspects of the membranes. No postoperative complications occurred, and both sites exhibited favorable alveolar ridge volume for implant placement.

CONCLUSIONS

The described triangle suture technique reliably stabilized GBR barrier membranes without the need for fixation hardware. Compared with suturing methods that limit graft volume and apply pressure over the grafted area, the triangle suture may offer clinical advantages.

Neodymium-Doped Yttrium Aluminum Garnet Laser Photobiomodulation May Improve Neurosensory Function after Surgical Injury to Cranial Nerve V: A Report of Three Consecutive Cases

OBJECTIVE

The purpose of this report was to document clinical responses to Nd:YAG laser energy in patients with surgical injury to terminal branches of the trigeminal nerve.

BACKGROUND

Limited evidence from in vitro, animal, and human studies suggests infrared laser energy may positively influence recovery after peripheral or cranial nerve injury, although clinical effects of neodymiumdoped yttrium aluminum garnet (Nd:YAG) lasers remain unstudied in this context.

METHODS

We applied Nd:YAG laser energy in the treatment of three consecutive patients presenting with altered neurosensory function following various oral and maxillofacial procedures. The time interval between surgical injury and laser photobiomodulation ranged from one week to two years.

RESULTS

All patients exhibited reduction in the area of diminished sensation and partial recovery of normal neurosensory function. The two patients with long-standing neurosensory deficiency experienced near complete recovery of intraoral sensation, with residual zones of diminished sensation from the perioral skin.

CONCLUSIONS

Although all patients in this case series demonstrated clinical improvements compared with baseline, controlled studies are needed to determine whether Nd:YAG laser energy accelerates or enhances recovery of neurosensory function after surgical nerve injury. Studies establishing the relative efficacies of Nd:YAG and diode lasers appear warranted.

Overlay Analysis of Cone-Beam Computed Tomography Volumes Acquired before and after Horizontal Alveolar Ridge Augmentation

OBJECTIVE

The objective of this study was to illustrate the efficacy of a novel imaging analysis technology to capture horizontal and vertical dimensional changes following horizontal alveolar ridge augmentation (HRA).

METHODS

Cone-beam computed tomography (CBCT) volumes from 65 HRA sites in 57 patients were available for evaluation, employing a three-dimensional analysis software to overlay preoperative and post-augmentation CBCT volumes. Horizontal and vertical alveolar ridge dimensional (HRD/VRD) changes were recorded considering a panel of patient-, site-, and procedure-related explanatory variables.

RESULTS

VRD changes ranged from -2.9 to 3.0 mm, more than half anterior sites losing alveolar ridge height. Mean HRD increase at the 3- and 5-mm levels apical to the alveolar crest amounted to 2.3±1.6 and 2.4±1.3 mm, respectively, membrane fixation and non-resorbable membrane use associated with significantly greater gains.

CONCLUSIONS

To date, studies reporting dimensional changes following HRA predominantly rely on serial in situ orofacial caliper recordings omitting vertical alterations. The protocol employed in this study allows simultaneous HRD and VRD evaluations and assures baseline and post-augmentation recordings are made at the same alveolar ridge position. Compared with in situ recording, CBCT overlay analysis may achieve a more complete characterization of dimensional changes following HRA.

Time- and Species-Dependent Bacterial Adhesion to Titanium over Short Exposure Periods: An In Vitro Study

A considerable percentage of dental implant patients experience biofilm-mediated peri-implant disease following transmucosal abutment application. Bacterial adhesion is an early step in biofilm development. Our purpose was to assess adhesion of specific bacterial species to titanium over short exposure periods. Eight bacterial species were selected for this analysis: Streptococcus oralis, Streptococcus mitis, Gemella haemolysans, Streptococcus gordonii, Streptococcus sanguinis, Neisseria flavescens, Streptococcus salivarius, and Pseudomonas aeruginosa. We cultured each species with appropriate media and exposed titanium foil discs to the bacteria for 60, 15, 5, 1, or 0.25 minutes. Optical density at 600-nm wavelength (OD600) was assessed for the baseline inoculum and each species/exposure combination. The proportion of bacteria adherent to titanium was determined for each experimental condition. Striking titanium adhesion was noted for all evaluated species even when exposure time was limited to 15 seconds. Strategies to limit bacterial adhesion at dental implant surfaces may offer potential for improved treatment outcomes and preservation of peri-implant health.

Extension of charged-particle spectrometer capabilities for diagnosing implosions on OMEGA, Z, and the NIF

New designs and a new analysis technique have been developed for an existing compact charged-particle spectrometer on the NIF and OMEGA. The new analysis technique extends the capabilities of this diagnostic to measure arbitrarily shaped ion spectra down to 1 MeV with yields as low as 10⁶. Three different designs are provided optimized for the measurement of DD protons, T³He deuterons, and ³He³He protons. The designs are highly customizable, and a generalized framework is provided for optimizing the design for alternative applications. Additionally, the understanding of the detector's response and uncertainties is greatly expanded upon. A new calibration procedure is also developed to increase the precision of the measurements.

Characterizing x-ray transmission through filters used in high energy density physics diagnostics

We report on the design and implementation of a new system used to characterize the energy-dependent x-ray transmission curve, Θ(E), through filters used in high-energy density physics diagnostics. Using an Amptek X-123-CdTe x-ray spectrometer together with a partially depleted silicon surface barrier detector, both the energy spectrum and total emission of an x-ray source have been accurately measured. By coupling these detectors with a custom PROTO-XRD x-ray source with interchangeable cathodes, accurate characterizations of Θ(E) for filters of varying materials and thicknesses have been obtained. The validity of the technique has been confirmed by accurately reproducing areal densities for high-purity filters with known x-ray transmission properties. In this paper, the experimental setup is described and the results of absorption calibrations performed on a variety of different filters are presented.

Should periodontists prescribe postoperative oral corticosteroids to control pain and swelling? A systematic review

FOCUSED CLINICAL QUESTION

In generally healthy patients receiving third molar, periodontal, or dental implant surgery, do postoperative oral corticosteroids effectively limit pain and swelling compared with placebo or alternative medications?

Factors Affecting the Robustness of Data Inversion for Stable Isotope Measurement Using the Double Spike Method: Insights from Chromium Isotope Analysis

Stable isotope ratios are widely used to solve environmental, geological, medical, and forensic problems. The double spike technique is considered to be one of the most robust and efficient methods to correct for instrumental mass bias and isotopic fractionation that may occur during sample preparation. However, various hidden errors can arise from data processing and have been largely overlooked in previous studies. Several of these hidden errors were investigated in this work using measurement and synthetic data. Double spike inversion of chromium isotope raw data from 1116 natural samples demonstrated that averaging raw isotope ratios before double spike inversion can add significant errors to inverted isotope values, and such errors can be 1.5 times larger than the true analytical precision. Synthetic data were used to investigate the errors on inverted Cr isotope data caused by spike:analyte ratio and Fe-Ti-V interferences, and the following threshold values are recommended to minimize such errors: ⁵⁴Cr_spike/⁵²Cr_sample ratio greater than 0.5, ⁵⁶Fe/⁵²Cr less than 0.2, ⁴⁹Ti/⁵²Cr less than 0.04, and ⁵¹V/⁵²Cr less than 1. Sample preparation can potentially lead to large errors in inverted Cr isotope data if preparation-induced isotope fractionation deviates from the exponential law used in the double spike inversion, but such errors can be minimized by achieving >70% Cr yield. Our findings provide important insights for the double spike inversion procedure and assessing the reliability of inverted isotope data for not only the chromium isotope system but also other elements commonly analyzed using the double spike technique.

Yield degradation due to laser drive asymmetry in D3He backlit proton radiography experiments at OMEGA

Mono-energetic proton radiography is a vital diagnostic for numerous high-energy-density-physics, inertial-confinement-fusion, and laboratory-astrophysics experiments at OMEGA. With a large number of campaigns executing hundreds of shots, general trends in D³He backlighter performance are statistically observed. Each experimental configuration uses a different number of beams and drive symmetry, causing the backlighter to perform differently. Here, we analyze the impact of these variables on the overall performance of the D³He backlighter for proton-radiography studies. This study finds that increasing laser drive asymmetry can degrade the performance of the D³He backlighter. The results of this study can be used to help experimental designs that use proton radiography.

Orthodontic Treatment of Periodontally Compromised Teeth After Laser Periodontal Therapy: A Case Report

Objective: To assess stability of laser periodontal therapy (LPT) results after orthodontic tooth movement. Background: Periodontitis and malocclusion each exhibit high global prevalence. Thus, dentists inevitably face increasing demand for orthodontic treatment in patients with reduced periodontal support. Many of these patients benefit from orthodontic treatment, provided that periodontal inflammation is controlled. Materials and methods: We present a case demonstrating successful orthodontic treatment of periodontally compromised teeth after LPT. A patient with severe attachment and alveolar bone loss received orthodontic treatment 13 months after neodymium-doped: yttrium aluminum garnet LPT (1064 nm). We utilized three laser parameter sets for various purposes during the procedure-ablation of the periodontal pocket epithelium (2.8 W, 20 Hz, 100 μs), clot stabilization (2.8 W, 20 Hz, 550 μs), and photobiomodulation (2.8 W, 20 Hz, 100 μs, noncontact). Results: Treatment resulted in improved radiographic bone levels, clinical parameters consistent with periodontal health, and favorable occlusal relationships. Conclusions: In the presented case, we successfully treated a patient presenting with malocclusion and reduced periodontal support while avoiding the risk and morbidity of conventional periodontal surgery. Controlled clinical research to establish the predictability of the described approach appears warranted.

Response of CR-39 nuclear track detectors to protons with non-normal incidence

This paper presents data from experiments with protons at non-normal incidence to CR-39 nuclear track detectors, analyzing the properties of detection efficiency, proton track diameter, track contrast, and track eccentricity. Understanding the CR-39 response to protons incident at an angle is important for designing charged particle detectors for inertial confinement fusion (ICF) applications. This study considers protons with incident energies less than 3 MeV. In this regime, an incident angle of 10° has no effect on CR-39 detection efficiency, and >85% detection efficiency is preserved up through 25° in the range of 1.0 MeV-2.1 MeV. For ICF applications, incident angles above 30° are deemed impractical for detector design due to significant drops in proton detection at all energies. We observe significant reductions in detection efficiency compared to theoretical predictions, particularly at low energies where proton tracks are etched away. The proton track diameter measured by the scan system is observed to decrease with higher incident angles. The track diameters are analyzed with two fitting models, and it is shown that the diameter-energy relation can be fit with the existing models at angles up to 30°. The optical contrast of the tracks tends to increase with the angle, meaning that the tracks are fainter, and a larger increase is observed for higher energies. Eccentricity, a measure of how elongated proton tracks are, increases with the incident angle and drops after the critical angle. The lowest energy tracks remain nearly circular even at higher angles.

Fracture necrosis: A risk indicator for tooth loss

BACKGROUND AND OVERVIEW

The term "fracture necrosis" has been used to describe the condition found in a minimally restored tooth without a history of trauma when the suspected etiology for the loss of pulpal vitality is a crown-originating fracture. Teeth with fracture necrosis have a poor prognosis, and, when accompanied by characteristic radiographic findings, extraction may be considered the primary treatment option.

CASE DESCRIPTIONS

Two adult men with crown-originating fractures and suspected fracture necrosis had localized periodontal bone and attachment loss associated with severe pain on mastication from mandibular second molars. In case 1, the patient desired to retain the tooth despite an unfavorable prognosis. Nonsurgical root canal therapy and a crown prolonged tooth survival for only 30 months. The patient in case 2 requested extraction after a thorough review of his dental condition and tooth prognosis.

CONCLUSIONS

A tooth with fracture necrosis may continue to harbor virulent microorganisms after root canal therapy. When these microorganisms have access to the periodontal attachment, progressive loss of supporting tissues can be expected.

PRACTICAL IMPLICATIONS

When weighing treatment options for teeth with fracture necrosis associated with characteristic radiographic findings, preference toward extraction and tooth replacement, rather than treatment aimed at tooth retention, may represent a sound clinical approach.

Managing Antral Wall Discontinuities in Sinus Elevation Surgery

INTRODUCTION

Schneiderian membrane perforation (SMP), which is usually readily manageable, is the most common intraoperative complication of sinus elevation surgery. Some evidence suggests that SMP is associated with increased risk for postoperative complications, including maxillary sinusitis. Antral wall discontinuity (AWD) is an acquired condition that may increase SMP likelihood and lead to larger, less-manageable perforations.

CASE PRESENTATION

A generally healthy patient receiving sinus elevation surgery exhibited an AWD in the palatine process of the maxilla. The osseous defect was isolated intraoperatively, and the Schneiderian membrane was sharply dissected from the palatal connective tissue. Favorable augmentation of the maxillary sinus was noted on cone-beam computed tomography (CBCT) assessment at postoperative month 34.

CONCLUSIONS

AWD (fusion of the Schneiderian membrane with the periosteum of the maxilla) is a condition identifiable on preoperative CBCT images, which may increase the incidence and severity of SMP during sinus elevation procedures. Careful assessment for integrity of antral osseous walls before surgery is essential. Presence of AWD may obligate modifications to the surgical plan, or in some cases, contraindicate sinus elevation surgery.

Utilizing the Regional Acceleratory Phenomenon and Dental Implant Anchorage for Distalization and Intrusion of a Mesially Tipped Mandibular Molar: A Case Report

INTRODUCTION

Introduction of a surgical insult in conjunction with orthodontic therapy has been shown to accelerate treatment in minor tooth movement and comprehensive orthodontic cases by induction of the regional acceleratory phenomenon (RAP). When applying this concept to a molar tipped into an adjacent edentulous site, a dental implant can be planned to anchor the movement.

CASE PRESENTATION

A generally and periodontally healthy 25-year-old patient presented missing tooth #19, with tooth #18 mesially tipped into the first molar crown space. A dental implant was placed in the #19 position. Following osseointegration, the implant anchored orthodontic movement of the adjacent tooth, which was initiated in conjunction with third molar extraction.

CONCLUSION

Favorable biomechanics for molar uprighting can be achieved using an osseointegrated implant and a customized orthodontic device. The presented technique facilitates implant site development without delaying placement of the fixture and simplifies fabrication of a harmonious and anatomic implant-supported restoration. Induction of the RAP may hasten treatment completion.

Microbial U Isotope Fractionation Depends on the U(VI) Reduction Rate

U isotope fractionation may serve as an accurate proxy for U(VI) reduction in both modern and ancient environments, if the systematic controls on the magnitude of fractionation (ε) are known. We model the effect of U(VI) reduction kinetics on U isotopic fractionation during U(VI) reduction by a novel Shewanella isolate, Shewanella sp. (NR), in batch incubations. The measured ε values range from 0.96 ± 0.16 to 0.36 ± 0.07‰ and are strongly dependent on the U(VI) reduction rate. The ε decreases with increasing reduction rate constants normalized by cell density and initial U(VI). Reactive transport simulations suggest that the rate dependence of ε is due to a two-step process, where diffusive transport of U(VI) from the bulk solution across a boundary layer is followed by enzymatic reduction. Our results imply that the spatial decoupling of bulk U(VI) solution and enzymatic reduction should be taken into account for interpreting U isotope data from the environment.

Decisions Before Incisions: Technique Selection for the Distal Wedge Procedure

FOCUSED CLINICAL QUESTION

What factors identify the optimal surgical technique when a distal wedge procedure is indicated at a terminal maxillary or mandibular molar site?

SUMMARY

Incision design for the distal wedge procedure is based primarily on the dental arch (maxilla or mandible), the distance from the terminal molar to the hamular notch or ascending ramus, and the dimensions of the attached gingiva.

CONCLUSIONS

In most situations, favorable clinical results are achievable irrespective of the chosen distal wedge method, and technique selection is based more on operator preference than evidence. However, anatomic limitations can render distal wedge procedures challenging in some cases, and procedural advantages of specific techniques can simplify treatment. One systematic approach to distal wedge technique selection is presented in this report. Additionally, a laser-assisted distal wedge protocol is presented for cases in which unfavorable tooth-to-ramus distance or presence of a prominent external oblique ridge contraindicates conventional distal wedge techniques.

Frequency of adequate mesiodistal space and faciolingual alveolar width for implant placement at anterior tooth positions

BACKGROUND

Prior studies have defined minimum mesiodistal space (MS) and faciolingual alveolar width (FAW) requirements for dental implant sites, and failure to observe these constraints may adversely impact peri-implant health and esthetics. However, to the authors' knowledge, no previous reports have established frequencies at which anterior tooth positions present favorable MS and FAW for implant accommodation.

METHODS

A single examiner analyzed 205 cone-beam computed tomographic images, recording MS and FAW available for implant placement at anterior tooth positions. The examiner compared measurements with standardized implant diameters to assess anticipated implant-to-tooth distances and peri-implant bone thicknesses.

RESULTS

In the esthetic zone, lateral incisor sites most frequently failed to present favorable MS. At maxillary lateral incisor positions, 22% (left) and 27% (right) of sites offered less than 2 millimeters between the proposed implant platform and the adjacent teeth. In mandibular incisor positions, implant-to-tooth distance was less than 2 mm at 79% through 97% of sites and less than 1.5 mm at 35% through 76% of sites. Over one-half of maxillary incisor sites and 78% through 95% of mandibular incisor sites exhibited FAW of less than 4 mm beyond implant diameter.

CONCLUSIONS

In the population evaluated, mandibular incisor positions frequently presented unfavorable MS to accommodate conventional narrow-diameter implants. In addition, considerable proportions of mandibular incisor and maxillary lateral incisor sites may be at risk of developing unfavorable peri-implant bone thickness when conventional narrow-diameter implants are used.

PRACTICAL IMPLICATIONS

Practitioners should consider small-diameter implants and nonimplant tooth replacement methods for many patients missing single mandibular incisors or maxillary lateral incisors.

Rational Prophylactic Antibiotic Selection for Sinus Elevation Surgery

FOCUSED CLINICAL QUESTION

For a generally healthy patient with no risk indicators for postoperative infection, what is the most appropriate perioperative antibiotic regimen for sinus elevation surgery in terms of reducing postoperative infection risk and minimizing untoward effects?

CLINICAL SCENARIO

A 38-year-old female patient in good general and periodontal health presents missing tooth #14 (Fig. ). She reports no systemic conditions, no history of sinusitis, and no allergies. Medications include acetaminophen and ibuprofen as needed for pain. The patient's dentition is minimally restored, with no active caries. Cone-beam computed tomography reveals a clear, pneumatized left maxillary sinus and inadequate bone volume to support dental implant placement (Fig. ). No septa or pathologic lesions are present, the ostium appears patent, and no thickening of the Schneiderian membrane is appreciable. The patient states that she wants to replace her missing molar without restoring adjacent teeth (Figs. and ). [Figure: see text] [Figure: see text] [Figure: see text] [Figure: see text].

The Tissue-Supported Sling Suture: Technique and Clinical Applications

INTRODUCTION

Continuous and interrupted sling sutures (ISSs) are used around teeth in contemporary periodontics. However, conventional ISSs depend upon favorable tooth morphology for stability through the early healing period. The purpose of this report is to present a variation of the classic ISS that does not rely on favorable tooth morphology.

CASE SERIES

Tissue-supported sling sutures (TSSs) were used for six patients undergoing root coverage, gingival augmentation, or pontic site development (guided bone regeneration) procedures.

CONCLUSIONS

Although techniques such as vertical mattress suturing may support greater coronal flap advancement, the TSS technique does maintain coronal flap position while minimizing trauma to papillae. TSS stability is independent of tooth morphology and may offer clinicians flexibility in achieving reliable closure over hard and soft tissue implants. Like mattress sutures, TSSs reduce tension at the crestal incision line in tissue grafting procedures.

Focus on Epithelialized Palatal Grafts. Part 3: Methods to Enhance Patient Comfort at Palatal Donor Sites

INTRODUCTION

Postoperative discomfort is a documented complication of the epithelialized palatal graft (EPG) procedure, and the expectation of an unpleasant patient experience may cause some practitioners to avoid EPG altogether. However, EPG affords distinct advantages in a variety of clinical situations, and the postoperative discomfort associated with the procedure can be minimized.

CASE SERIES

Three generally and periodontally healthy patients with gingival recession defects and minimal zones of attached gingiva received mandibular anterior EPG procedures. In all cases, collagen membranes were trimmed to fit the palatal donor sites and sutured in place. Two patients reported minimal donor site discomfort at any time point. One patient with large bilateral donor sites reported moderate palatal discomfort limited to the first postoperative week. All patients reported overall positive treatment experiences.

CONCLUSIONS

Placement of a resorbable collagen membrane at large EPG harvest sites appears to limit topical irritation of the wound and may substantially improve patient comfort postoperatively. Combining local and systemic measures to minimize patient discomfort may render EPG procedures very tolerable for patients. Controlled clinical trials comparing patient-centered outcomes following EPG harvest with and without collagen membrane placement appear warranted.

Focus on Epithelialized Palatal Grafts. Part 2: Implant Site Development

INTRODUCTION

The epithelialized palatal graft (EPG), introduced in 1963, has persisted as the gold standard for gingival augmentation, and in the present era, mucosal augmentation around dental implants has become an important concern. A limited body of evidence suggests peri-implant mucosal augmentation may favorably impact bone and mucosal stability and peri-implant health under some circumstances. Although more contemporary procedures for peri-implant mucosal augmentation are often preferred based on convenience and esthetic considerations, EPG augmentation at dental implant sites is distinguishable from methods which do not deepen the vestibule and eliminate unfavorable superficial soft tissue. Implant sites augmented with EPG are qualitatively distinct from sites augmented using other methods.

CASE SERIES

Seven generally healthy patients received EPG augmentation before dental implant placement, at implant placement, before implant uncovering, or after implant uncovering. In each case, the patient exhibited a favorable zone of attached peri-implant mucosa following treatment.

CONCLUSIONS

Reliable mucosal augmentation with EPG is achievable at multiple phases in the course of dental implant therapy. EPG augmentation offers distinct clinical advantages and may be preferable to other mucosal augmentation strategies at some dental implant sites.

Adjunctive Nd:YAG Laser Irradiation for Ridge Preservation and Immediate Implant Procedures: A Consecutive Case Series

INTRODUCTION

Whether or not laser use provides any meaningful benefit at immediate implant and ridge preservation sites remains an open question in periodontics. However, various lasers have been used in conjunction with tooth extraction and immediate implant placement. Evidence supporting adjunctive laser irradiation at immediate implant and ridge preservation sites is mostly limited to preclinical studies and a small number of case reports.

CASE SERIES

Adjunctive neodymium‒doped: yttrium, aluminum, garnet (Nd:YAG) laser irradiation was used at six immediate implant sites and five ridge preservation sites. Three immediate implants were in maxillary incisor positions and three were in premolar positions, two maxillary and one mandibular. All cases exhibited favorable healing and satisfactory clinical outcomes.

CONCLUSIONS

Nd:YAG laser energy application with 650-µs pulse duration consistently supported rapid clot formation and graft containment at immediate implant and ridge preservation sites. Histologic analyses and controlled clinical trials comparing ridge preservation and immediate implant procedures with and without laser use are needed. Because cellular responses and clinical outcomes may be exquisitely sensitive to irradiation parameters, studies should report materials and methods in detail.

Potential Metabolomic Linkage in Blood between Parkinson's Disease and Traumatic Brain Injury

The etiologic basis for sporadic forms of neurodegenerative diseases has been elusive but likely represents the product of genetic predisposition and various environmental factors. Specific gene-environment interactions have become more salient owing, in part, to the elucidation of epigenetic mechanisms and their impact on health and disease. The linkage between traumatic brain injury (TBI) and Parkinson's disease (PD) is one such association that currently lacks a mechanistic basis. Herein, we present preliminary blood-based metabolomic evidence in support of potential association between TBI and PD. Using untargeted and targeted high-performance liquid chromatography-mass spectrometry we identified metabolomic biomarker profiles in a cohort of symptomatic mild TBI (mTBI) subjects (n = 75) 3⁻12 months following injury (subacute) and TBI controls (n = 20), and a PD cohort with known PD (n = 20) or PD dementia (PDD) (n = 20) and PD controls (n = 20). Surprisingly, blood glutamic acid levels in both the subacute mTBI (increased) and PD/PDD (decreased) groups were notably altered from control levels. The observed changes in blood glutamic acid levels in mTBI and PD/PDD are discussed in relation to other metabolite profiling studies. Should our preliminary results be replicated in comparable metabolomic investigations of TBI and PD cohorts, they may contribute to an "excitotoxic" linkage between TBI and PD/PDD.

Field Application of 238U/235U Measurements To Detect Reoxidation and Mobilization of U(IV)

Biostimulation to induce reduction of soluble U(VI) to relatively immobile U(IV) is an effective strategy for decreasing aqueous U(VI) concentrations in contaminated groundwater systems. If oxidation of U(IV) occurs following the biostimulation phase, U(VI) concentrations increase, challenging the long-term effectiveness of this technique. However, detecting U(IV) oxidation through dissolved U concentrations alone can prove difficult in locations with few groundwater wells to track the addition of U to a mass of groundwater. We propose the ²³⁸U/²³⁵U ratio of aqueous U as an independent, reliable tracer of U(IV) remobilization via oxidation or mobilization of colloids. Reduction of U(VI) produces ²³⁸U-enriched U(IV), whereas remobilization of solid U(IV) should not induce isotopic fractionation. The incorporation of remobilized U(IV) with a high ²³⁸U/²³⁵U ratio into the aqueous U(VI) pool produces an increase in ²³⁸U/²³⁵U of aqueous U(VI). During several injections of nitrate to induce U(IV) oxidation, ²³⁸U/²³⁵U consistently increased, suggesting ²³⁸U/²³⁵U is broadly applicable for detecting mobilization of U(IV).

Tunnel Access for Guided Bone Regeneration in the Maxillary Anterior

INTRODUCTION

Minimally invasive surgical techniques in periodontics, including methods for ridge augmentation, have been shown to achieve surgical goals while minimizing swelling, decreasing postoperative discomfort, and enhancing soft tissue architecture. The present case illustrates a minimally invasive guided bone regeneration technique for augmentation of a deficient alveolar ridge in the esthetic zone.

CASE PRESENTATION

A 30-year-old patient received localized ridge augmentation utilizing tunnel access for guided bone regeneration with a dense polytetrafluoroethylene membrane and a freeze-dried bone allograft. The patient experienced minimal postoperative swelling and discomfort, and the procedure resulted in favorable ridge dimensions for implant placement.

CONCLUSIONS

The tunnel access for guided bone regeneration presented in this case may offer advantages similar to other minimally invasive ridge augmentation techniques. Further controlled clinical study is warranted.