Reactivity and Selectivity of Azaspirocycles in Radical C-H Functionalization.

Investigations of saturated spirocycles toward selective C-H functionalization reactions are scarce, despite their potential applications. In this work, we uncovered fundamental reactivity and selectivity differences between saturated heterocycles and their spirocyclic analogues using a model radical C-H xanthylation coupled with computational analysis. Ultimately, this study sheds light on the fundamental, understudied radical reactivity of spirocycles, thereby allowing for a pronounced chemical tunability that will prove to be advantageous in the expansion of their chemical space and applications in medicinal chemistry.

Remote assessment of DMFT and number of implants with intraoral digital photography in an elderly patient population - a comparative study.

OBJECTIVES: This comparative study aimed to evaluate intraoral digital photography (IODP) as assessment-tool for DMFT and number of implants (IMPL) compared to clinical diagnosis (CLIN) in an elderly population with high restorative status. Secondary research questions were whether an additional evaluation of panoramic radiographs (PAN-X) or raters' clinical experience influence the agreement. METHODS: Fifty patients (70.98±7.60 years) were enrolled for standardized CLIN and IODP. The clinical reference examiner and ten blinded raters evaluated the photographs without and with a PAN-X regarding DMFT and IMPL. CLIN were used as reference standard and differences to IODP and IODP-PAN-X findings were analysed descriptively. To assess intra-rater agreement, pairwise Gwet's AC1s of the three diagnostic methods CLIN, IODP and IODP+PAN-X were calculated. RESULTS: Compared to a DMFT of 22.10±3.75 (CLIN), blinded raters evaluated a DMFT of 21.54±3.40 (IODP) and 22.12±3.45 (IODP+PAN-X). Mean values for "Decayed" were 0.18±0.52 (CLIN), 0.45±0.46 (IODP) and 0.48±0.47 (IODP-PAN-X), while 11.02±5.97 (CLIN), 10.66±5.78 (IODP) and 10.93±5.91 (IODP+PAN-X) were determined for "Missing" and 10.90±5.61 (CLIN), 10.43±4.85 (IODP) and 10.71±5.11 (IODP+PAN-X) for "Filled". IMPL were 0.78±2.04 (CLIN), 0.58±1.43 (IODP), 0.78±2.04 (IODP+PAN-X). Gwet's AC1 using the mode of the blinded raters' assessment of "Decayed", "Missing" and IMPL compared to CLIN ranged from 0.81 to 0.89 (IODP) and 0.87 to 1.00 (IODP+PAN-X), while for "Filled" and DMFT they were 0.29 and 0.36 (IODP) as well as 0.33 and 0.36 (IODP+PAN-X), respectively. Clinical experience did not influence the agreement. CONCLUSIONS: Assessment of "Decayed", "Missing" and IMPL by IODP showed almost perfect agreement, whereas of "Filled" and DMFT revealed fair to moderate agreement with clinical findings. Additional PAN-X-evaluation increased agreement compared to IODP-diagnostics alone. IODP for the assessment of DMFT and IMPL might be a suitable method in large-scale epidemiological studies, considering high agreement in total values and miscellaneous agreement at patient-level.

The impact of splinting timepoint of mobile mandibular incisors on the outcome of periodontal treatment-preliminary observations from a randomized clinical trial.

OBJECTIVES: To compare the outcome of periodontal parameters in mobile mandibular incisors which were splinted before or after full-mouth disinfection (FMD). MATERIALS AND METHODS: Thirty-four periodontitis patients with ≥ 1 mobile mandibular incisor (mobility degree II/III, clinical attachment loss (CAL) ≥ 5 mm, relative bone loss ≥ 50%) were randomly allocated to group A or B. Patients received periodontal treatment (PT) including splinting of teeth 33-43 before (A) or after FMD (B). Patient (age/sex/smoking status/systemic diseases/number of teeth) and tooth-related parameters (mean probing pocket depth (PPD)/CAL/oral hygiene indices; for the overall dentition and region 33-43) were assessed prior to PT and 12 months after FMD by a blinded examiner. Therapy-related information was added (group/antibiotic therapy/surgical intervention). RESULTS: Twenty-six patients (A: 12; B:14) were re-examined. Two patients of group B did not need splinting after FMD because of reduction in mobility after FMD. Regression analysis revealed a positive association of antibiotic therapy with CAL_overall, PPD_overall, and PPD_33-43 (p ≤ 0.01). There is a trend toward a higher reduction of periodontal parameters at teeth 33-43 in group A (PPD_33-43: - 0.91 vs. - 0.27 mm; CAL_33-43: - 1.02 vs. - 0.47 mm). CONCLUSIONS: Teeth splinted before or after FMD show a significant improvement in periodontal parameters 12 months after FMD. Splinting after FMD offered the option to detect reduction in mobility. CLINICAL RELEVANCE: Despite a higher, but not statistically significant, improvement in periodontal parameters on teeth splinted before FMD, the results do not indicate which timepoint of splinting is more beneficial. The decision for the therapeutic procedure should therefore be made individually.

The impact of splinting mobile mandibular incisors on Oral Health-Related Quality of Life-Preliminary observations from a randomized clinical trial.

AIM: To compare the Oral Health-Related Quality of Life (OHRQoL) of patients with mobile mandibular incisors before and after full-mouth disinfection (FMD) with and without splinting. MATERIAL AND METHODS: Thirty-four periodontitis patients with ≥1 mobile mandibular incisor (degree II/III) were randomly allocated to the test or control group. All patients received FMD and the test group additional splinting of teeth 33-43. OHRQoL was assessed before (BL) and 3 months after FMD (RE) using the Oral Health Impact Profile (OHIP)-14. Data were compared within and between the groups (Wilcoxon test/Mann-Whitney U test). RESULTS: Twenty-eight patients (13 test group/15 control group) were re-evaluated. FMD led to a reduction of the mean probing pocket depth (PPD; in mm) (test group: BL-PPD 3.89 ± 1.03, RE-PPD 2.82 ± 0.53; control group: BL-PPD 3.58 ± 0.66, RE-PPD 2.77 ± 0.59; each p ≤ .001), the mean clinical attachment level (CAL; in mm) (test group: BL-CAL 5.22 ± 1.38, RE-CAL 4.79 ± 0.85; control group: BL-CAL 4.58 ± 1.10, RE-CAL 4.41 ± 0.96; each p ≤ .05), and the mean OHIP-14 summary scores (test group: BL-OHIP 21.7 ± 11.06, RE-OHIP 9.9 ± 8.96, p = .0046; control group: BL-OHIP 16.8 ± 8.27, RE-OHIP 11.7 ± 8.55; p = .0217). The reduction of the OHIP-G14 scores was considerably higher in the test group but statistically not significant (p = .080). CONCLUSIONS: The results show a positive impact of non-surgical periodontal treatment on OHRQoL and a possible tendency for further improvement by splinting mobile mandibular incisors.

Secondary Electron Emission by Plasmon-Induced Symmetry Breaking in Highly Oriented Pyrolytic Graphite.

Two-particle spectroscopy with correlated electron pairs is used to establish the causal link between the secondary electron spectrum, the (π+σ) plasmon peak, and the unoccupied band structure of highly oriented pyrolytic graphite. The plasmon spectrum is resolved with respect to the involved interband transitions and clearly exhibits final state effects, in particular due to the energy gap between the interlayer resonances along the ΓA direction. The corresponding final state effects can also be identified in the secondary electron spectrum. Interpretation of the results is performed on the basis of density-functional theory and tight-binding calculations. Excitation of the plasmon perturbs the symmetry of the system and leads to hybridization of the interlayer resonances with atomlike σ^{*} bands along the ΓA direction. These hybrid states have a high density of states as well as sufficient mobility along the graphite c axis leading to the sharp ∼3 eV resonance in the spectrum of emitted secondary electrons reported throughout the literature.

Changes of clinical parameters at implants: A retrospective comparison of implants versus natural teeth over 5 years of supportive periodontal therapy.

OBJECTIVES: To compare clinical parameters of implants versus natural teeth over a period of 5 years during supportive periodontal therapy (SPT). MATERIAL AND METHODS: A total of 421 SPT patients were screened for implants (I) and corresponding control teeth (C). Data (patient level [P ]: sex, age, smoking status, systemic diseases, adherence, oral hygiene indices, mean probing depth [PD]P , bleeding on probing [BOP]P , periodontal risk profile; implant/control tooth level [I/C ]: PDI/C , BOPI/C ; site level at implants [SITE ]: position, dental arch, aspect, BOPSITE ) were assessed at the first SPT session where the implant was probed (T1) and 5 years later (T2). The influence of patient and implant/control-related factors on PDI/C /BOPI/C was tested (linear mixed model) as well as the influence of site-specific factors on the PDSITE change (multilevel regression). RESULTS: A total of 70 patients (151 implants) were included. Mean PDI was 2.75 ± 0.85 mm (T1) and 2.87 ± 0.79 mm (T2). Mean PDC was 2.42 ± 0.66 mm (T1) and 2.49 ± 0.71 mm (T2). BOPI increased from 8.62 ± 15.01% (T1) to 24.06 ± 26.79% (T2) and BOPC from 9.97 ± 17.78% (T1) to 15.52 ± 22.69% (T2). The differences between implants and controls were significant for BOP (p = .0032). At T2, BOPI/C was associated with periodontal risk (p = .0351). The site-specific analysis revealed an association of BOPSITE at T1 with the progression of PDSITE (p = .0058). CONCLUSIONS: Probing depths of implants and controls seem to change similarly during SPT but retention of inflammation-free conditions at implants appears to be more difficult compared to natural teeth. Patients with a high-risk profile appear to have an increased susceptibility for BOP around implants, and BOP at implants seems to be a predictor for further PD increase.