Titanium implants have revolutionized restorative and reconstructive therapy, yet achieving optimal osseointegration and ensuring long-term implant success remain persistent challenges. In this review, we explore a cutting-edge approach to enhancing implant properties: ultraviolet (UV) photofunctionalization. By harnessing UV energy, photofunctionalization rejuvenates aging implants, leveraging and often surpassing the intrinsic potential of titanium materials. The primary aim of this narrative review is to offer an updated perspective on the advancements made in the field, providing a comprehensive overview of recent findings and exploring the relationship between UV-induced physicochemical alterations and cellular responses. There is now compelling evidence of significant transformations in titanium surface chemistry induced by photofunctionalization, transitioning from hydrocarbon-rich to carbon pellicle-free surfaces, generating superhydrophilic surfaces, and modulating the electrostatic properties. These changes are closely associated with improved cellular attachment, spreading, proliferation, differentiation, and, ultimately, osseointegration. Additionally, we discuss clinical studies demonstrating the efficacy of UV photofunctionalization in accelerating and enhancing the osseointegration of dental implants. Furthermore, we delve into recent advancements, including the development of one-minute vacuum UV (VUV) photofunctionalization, which addresses the limitations of conventional UV methods as well as the newly discovered functions of photofunctionalization in modulating soft tissue and bacterial interfaces. By elucidating the intricate relationship between surface science and biology, this body of research lays the groundwork for innovative strategies aimed at enhancing the clinical performance of titanium implants, marking a new era in implantology.

Purpose: Fixed restorations and dental enamel have different structures that produce different wear on opposing teeth, resulting in clinical problems. Therefore, it is necessary to determine the type of restoration that causes less wear on naturally opposing teeth to make recommendations. The objective of this study was to systematically analyze the evidence from observational studies and clinical trials on enamel wear in different ceramic restorations.

Study selection: The designs of the included studies were randomized clinical trials (RTCs), non-randomized clinical trials (non-RTCs), and observational studies (OS). The studies must answer the research question, be available in full text, be written in English or Spanish, and have had at least six months of follow-up. Protocol number: CRD42023397759.

Results: After screening 499 records, 20 RTCs were subjected to data extraction, 10 were excluded, 10 were included in the systematic review, and only 5 were included in the network meta-analysis. The risk of bias assessment reported moderate to high risk of bias, quality, and certainty of evidence was evaluated and rated as moderate. Network meta-analysis showed higher enamel wear was observed in natural dental enamel against metal-ceramic antagonists.

Conclusions: Enamel wear occurs in all teeth, even when the antagonist is a natural tooth. The wear is larger on surfaces with the ceramic crown antagonists studied (metal-ceramic, glazed zirconia, and polished zirconia). It is necessary to conduct additional clinical trials with larger follow-up periods and sample sizes.

Purpose: Additive cast-fabrication has yet to be used as commonly in implant prosthodontics as conventional methods. This review aimed to investigate the accuracy of additive cast-fabrication in implant prosthodontics.

Study selection: The study protocol was registered in the PROSPERO database (CRD42022374972). Reporting was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines, following the Cochrane Handbook. Two-arm interventional studies that matched the PICO were included (Population: dental typodonts with implants, Intervention: additive cast-fabrication, Comparator: conventional cast-fabrication, Outcome: positional deviations). A systematic search was conducted in three databases: PubMed (MEDLINE), EMBASE, and the Cochrane Library (CENTRAL).

Results: Seven papers were included in the analysis of horizontal, vertical, and root mean square (RMS) deviations. No significant differences were observed between groups. The overall vertical mean deviation of the intervention group was -4.15 µm [-24.88; 16.57], and the pooled mean absolute deviation was 22.43 µm [8.33; 36.54]. In the control group, these values were 19.67 µm [-32.71; 72.04] and 24.62 µm [0.00; 59.42], respectively. The overall horizontal mean deviation in the intervention group was 21.29 µm [-77.10; 119.68], and the pooled mean absolute deviation was 26.96 µm [0.00; 70.81]. In the control group, the overall mean was 1.45 µm [-32.26; 35.15] and the pooled mean absolute deviation was 25.05 µm [9.08; 41.01]. The mean RMS was only slightly larger in the intervention group, with the value of 14.74 µm [-107.26; 136.74].

Conclusions: Additive cast-fabrication is as accurate as the conventional method for the position of implant analogs.

Purpose: This network meta-analysis (NMA) of randomized controlled trials (RCTs) aimed to identify effective initial conservative treatment strategies for patients with temporomandibular joint disorders (TMD).

Study selection: RCTs comparing treatment options for TMD published between January 2000 and July 2021 were retrieved from the databases of PubMed and Embase via a comprehensive electronic search. Patients diagnosed with myalgia (muscle pain) or arthralgia (joint pain) according to pain-related Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) and the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) were eligible for inclusion. Twelve treatment options and a placebo were included in the mutual comparisons. The risk of bias was assessed using Risk of Bias 2.0. Forest plots of direct comparisons between individual studies were created using MetaInsight. NMA was performed using R statistical software (netmeta).

Results: Twenty-four RCTs involving 1336 patients assessing pain and 12 RCTs involving 614 patients assessing maximal mouth opening were identified. Low-level laser therapy (standard mean difference [SMD]: -2.12, 95% confidence interval [CI]: -3.18, -1.06), self-exercise (SMD: -1.51, 95% CI: -2.82, -0.2), and stabilization splints (SMD: -1.16, 95% CI: -2.02, -0.29) were effective in improving pain; however, the certainty of evidence was very low. Self-exercise (SMD: 0.71, 95% CI: -0.58, 2.01), stabilization splints (SMD: 0.65, 95% CI: -0.09, 1.39), and low-level laser therapy (SMD: 0.63, 95% CI: -0.34, 1.6) were effective in improving maximal mouth opening; however, the certainty of evidence was very low.

Conclusions: Stabilization splints, self-exercise, and low-level laser therapy may be effective in the initial treatment of TMD.

Purpose: This systematic review aims to assess the impact of different 3D printing orientations on the physico-mechanical properties, volumetric change, and accuracy of additively manufactured ceramic specimens, as well as their restorations.

Study selection: The web database containing records for building orientation of 3D-printed ceramics until January 2024 was searched, with no language limitations. PRISMA 2020 guidelines were followed, and the risk of bias was evaluated using the modified CONSORT checklist for laboratory studies on dental materials. The RevMan 5.4 of Cochrane collaboration was used for the meta-analysis with α<0.05.

Results: In this systematic review, 35 out of 2967 records were considered. The printing orientations had a significant influence on the mechanical properties of the additively manufactured specimens (P < 0.05), specifically, the horizontally printed specimens exhibited the best mechanical behavior, while the physical properties exhibited controversial results. Additionally, the printing orientations had a significant impact on the volumetric shrinkage and accuracy of molar teeth (P < 0.05).

Conclusions: The ideal mechanical outcome was observed when ceramic specimens were 3D-printed in a horizontal direction relative to the platform, while vertically printed specimens showed the worst properties. The printing orientations affect the volumetric change of the specimens; however, volumetric change highly depends on the sintering parameters. It is recommended to 3D print ceramic molar crowns at 180° with the occlusal surface facing the printing platform.

Clinical significance: Several factors affect the additively manufactured restorations throughout the printing procedure. Therefore, printing orientation should be carefully considered before the additive production process of ceramic restorations.

Purpose: Arthrogenic temporomandibular disorders (TMDs) that do not respond to conservative treatment necessitate the use of semi-conservative methods, such as arthrocentesis. However, the ranking of intraarticular devices used in arthrocentesis remains controversial. Therefore, a network meta-analysis and systematic review were conducted to compare the different materials used for arthrocentesis.

Study selection: Databases of Cochrane Library, EMBASE, PubMed, and Web of Science were searched systematically to retrieve randomized controlled trials (RCTs) published in English comparing the efficacy of different intraarticular materials used for arthrocentesis. The mean differences (MD) and 95% confidence interval (CI) were calculated for maximum mouth opening (MMO) and pain perception using Bayesian network meta-analysis.

Results: Among the 7674 studies retrieved, 13 RCTs were included in the quantitative synthesis. Evaluation of the short-term follow-up (1–3 months) outcomes revealed that saline-platelet-rich plasma (saline-PRP) and saline-steroid yielded the greatest improvement in MMO, with MDs of 3.49 (CI: –4.23, 10.81) and 3.36 (CI: –4.70, 10.46), respectively. Saline-PRP exhibited improvement in terms of pain reduction (MD=–2.72 (CI: -5.80, 0.35). Evaluation of the long-term follow-up outcomes revealed that saline-PRP yielded promising results for both outcomes: MD of 1.58 (CI: –6.84, 9.92) and –2.79 (CI: –9.44, 3.60) for MMO and pain reduction, respectively.

Conclusion: Saline-PRP injection led to a clinically noticeable shift in MMO and pain perception in the short term; in contrast, the results of saline-PRP, saline-hyaluronic acid (HA), and saline steroids were statistically insignificant. Saline-HA and saline-steroid effectively increased MMO in the long term, whereas saline-PRP yielded the most distinct reduction in pain.

Purpose: This study aimed to comprehensively summarize the current state, shortcomings, and challenges regarding the use of polyetheretherketone (PEEK) in various fields of stomatology.

Study selection: This study reviewed articles retrieved from PubMed, Google Scholar, Web of Science, and ScienceDirect databases. The main keywords used during the search included “polyetheretherketone (PEEK),” “dental materials,” “orthodontics,” “prosthodontics,” “oral implantology,” “oral and maxillofacial surgery,” “periodontics” “osseointegration,” and “surface modification.”

Results: Numerous studies have highlighted the properties of PEEK that contribute to its usefulness in dentistry, including its high biocompatibility, fracture resistance, aesthetics, radiolucency, and bone-like mechanical properties. Promising applications of PEEK in dentistry include orthodontic archwires, interceptive orthodontic appliances, fixed lingual retainers, crowns, post and cores, fixed partial dentures, removable partial dentures, maxillofacial prostheses, dental implants, implant abutments, alveolar bone scaffolds, jaw reconstruction, temporomandibular joint reconstruction, periodontal splints, and occlusal splints. In addition, many in vitro and in vivo experiments have demonstrated that the in vivo bone integration capability can be effectively improved using advanced surface modification technologies.

Conclusions: PEEK has been explored in several dentistry fields owing to its excellent properties. PEEK and its modifications are most frequently used in clinical dentistry. However, most of its applications are based on in vitro or short-term in vivo evaluations. Additional long-term clinical data are required to demonstrate the applicability and superiority of PEEK in dentistry.

Purpose: This study aimed to analyze how the wall thickness of 3D-printed hollow zirconia teeth affects shape accuracy.

Methods: Datasets with measurement points were created for different artificial teeth resembling the mandibular right first molar (Geomagic Design X, 3D Systems). Reference distances were 9.8 mm for mesio-distal direction (M-D), 10.9 mm for bucco-lingual direction (B-L), 7.0 mm for MB-BB and DB-BB, and 4.5 mm for ML-LB and DL-LB. The outer geometry was identical for all artificial teeth with wall thicknesses of 0.30, 0.50, 0.75, and 1.00 mm. Twenty zirconia teeth were fabricated using a 3D printer (CeraFab 7500 Dental, Lithoz) for each group and sintered before support removal. After performing analog distance measurements using a micrometer screw, the digital distance measurements and angular deviations between measurement points on 3D scans were analyzed. Possible effects were investigated using nonparametric ANOVA, followed by Tukey’s honest significant difference (HSD) test for multiple comparisons.

Results: The shape accuracy was acceptable for artificial teeth with wall thicknesses of ≥0.5 mm. The largest distance deviation was observed for a wall thickness of 0.3 mm. In particular, DB-BB showed a median deviation of >56.2 µm, which is significantly larger than that for other test groups, ranging from 7.4–9.5 µm (P < 0.05). In most cases, angular deviations were the largest for teeth with 0.3-mm wall thickness (11.6°) and remained below 5.0° for the other test groups.

Conclusions: Acceptable accuracy was obtained for artificial teeth with wall thicknesses of at least 0.5 mm.

Purpose: The lack of occlusal support reportedly reduces cognitive function; however, the underlying mechanisms remain unclear. The locus coeruleus, which is located adjacent to the trigeminal mesencephalic nucleus, secretes noradrenaline throughout the brain. In this study, we evaluated the effects of noradrenaline in the hippocampus and cerebral cortex on cognitive decline following tooth extraction in rats.

Methods: We performed passive avoidance experiments on male Wistar rats with extracted maxillary molars and determined the neuron density in the locus coeruleus and trigeminal mesencephalic nucleus using immunostaining and Nissl staining, respectively. We also assessed noradrenaline concentrations in the hippocampus and cerebral cortex using enzyme-linked immunosorbent assay.

Results: In the passive avoidance experiment, the latency in the bright compartment was significantly shorter (P < 0.05) in the extraction group than in the control group. The numbers of cells in the locus coeruleus and trigeminal nucleus were significantly lower (P < 0.05) in the extraction group compared to those in the control group. The noradrenaline levels in the hippocampus and cerebral cortex were also significantly lower (P < 0.05) in the extraction group than those in the control group.

Conclusions: The lack of occlusal support associated with tooth extraction reduces the number of cells in the trigeminal mesencephalic nucleus and locus coeruleus, which may reduce the supply of noradrenaline to the cerebral cortex and hippocampus, leading to a decline in cognitive function.

Purpose: The maintenance of peri-implant health relies significantly on the integrity of the peri-implant seal, particularly vulnerable at the interface between implant abutment and soft tissue. Early healing stages around implants involve cellular exposure to oxidative stress. This study aimed to investigate whether vacuum ultraviolet (VUV)-treated titanium augments the growth and functionality of human gingival fibroblasts while mitigating cellular stress.

Methods: Machined titanium plates underwent treatment with 172 nm VUV light for one minute, with untreated plates as controls. Human gingival fibroblasts were cultured on treated and untreated plates, and their behavior, growth, and functionality were assessed. Functionally impaired fibroblasts, treated with hydrogen peroxide, were also cultured on these titanium plates, and plate-to-plate transmigration ability was evaluated.

Results: Fibroblasts on VUV-treated titanium exhibited a 50% reduction in intracellular reactive oxygen species production compared to controls. Additionally, glutathione, an antioxidant, remained undepleted in cells on VUV-treated titanium. Furthermore, the expression levels of inflammatory cytokines IL-1β and IL-8 decreased by 40–60% on VUV-treated titanium. Consequently, fibroblast attachment and proliferation doubled on VUV-treated titanium compared to those in the controls, leading to enhanced cell retention. Plate-to-plate transmigration assays demonstrated that fibroblasts migrated twice as far on VUV-treated surfaces compared to those in the controls. In particular, the transmigration ability, impaired in functionally impaired fibroblasts on the controls, was preserved on VUV-treated titanium.

Conclusions: VUV-treated titanium promotes the growth, function, and migration of human gingival fibroblasts by reducing cellular stress and enhancing antioxidative capacity. Notably, the transmigration ability significantly improved on VUV-treated titanium.

Purpose: This study aimed to compare the deviation of hypermobile teeth in partially edentulous dental arches during impression taking using digital and conventional techniques.

Methods: A partially edentulous mandibular model with three target hypermobile teeth (including the left first premolar, #34; left second molar, #37; and right first premolar, #44), was used as the simulation model. After reference data were acquired using a desktop scanner, impressions of the simulation model were obtained using a digital intraoral scanner (IOS) and two conventional techniques (hydrocolloid material with a stock tray and silicone material with a custom tray as impression data (n=12/group). The three-dimensional accuracy (root mean square value) and two-dimensional accuracy (mesiodistal and buccolingual displacements) of the target teeth in each impression dataset were calculated based on the reference data. The comparison among three impression techniques was statistically performed using the Kruskal–Wallis test (α=0.05).

Results: For #34 and #44, the three- and two-dimensional accuracies of the impressions fabricated through data acquired through digital scanning (digital impression) were significantly superior to those of the hydrocolloid impression (P < 0.05), whereas no significant difference was found between the digital and silicone impressions. For #37, no significant difference in the accuracy of the impression data for the target teeth was observed among the three impression techniques.

Conclusions: Digital impression acquiring using an IOS is recommended over using a conventional hydrocolloid impression to prevent the deviation of hypermobile teeth in partially edentulous dental arches. Hypermobile tooth deviation in digital impression data depends on the tooth location.

Purpose: This in vitro study investigated the effect of build orientation on the wear resistance and hardness of denture teeth fabricated using digital light processing (DLP) compared to other denture tooth materials.

Methods: Disc-shaped specimens were prepared using denture tooth monomers and DLP devices in three build orientations: 0°, 45°, and 90°. Specimens of the same shape were fabricated using denture tooth materials for subtractive manufacturing, commercially available polymethylmethacrylate (PMMA) resin, and composite resin. The wear resistance was evaluated as the wear volume loss after 50,000 wear cycles using a ball-on-disc wear device in water for two-body wear and poppy seed slurry for three-body wear. The Vickers hardness values of the materials were measured. Two-way and one-way analyses of variance were performed for wear resistance and hardness, respectively, followed by Tukey’s honest significance test.

Results: The interaction between the denture tooth resins and maximum wear volume was significant (P < 0.01). The 0° build orientation exhibited the lowest wear volume in the three-body wear test and the highest hardness among the three build orientations. The 0° DLP-fabricated specimens demonstrated significantly less wear volume than that of the PMMA specimens and a wear volume comparable to that of the milled specimens. However, the 0° DLP-fabricated specimens showed significantly lower hardness than that of the milled and PMMA specimens. The composite resin specimens exhibited the highest wear resistance and hardness.

Conclusions: A 0° build orientation is recommended for DLP-fabricated denture teeth compared to 45° and 90° orientations to achieve greater wear resistance and hardness.

Purpose: To assess the radiographic outcomes, complications, and implant survival rates of advanced platelet-rich fibrin versus xenografts in hydraulic sinus floor elevation.

Methods: In this randomized trial, 40 patients with 46 implants were divided into two groups: a test group (advanced platelet-rich fibrin alone) and a control group (xenograft alone). The key outcome measures included bone regeneration, implant survival, and complications.

Results: Both groups achieved 100% implant survival. One case of maxillary sinus infection occurred in the control group after surgery. There was no significant difference in bone regeneration between the two groups at 6 months post-surgery and 12 months post-load (P > 0.05). The residual bone height and sinus width at the apex of the implant were significant negative predictors of bone regeneration (P < 0.05), whereas the presence of adjacent teeth was a significant positive predictor (P < 0.05).

Conclusions: Both advanced platelet-rich fibrin and xenografts effectively enhanced bone growth at sinus floor elevation, achieving high implant survival rates over one year. Advanced platelet-rich fibrin alone may be a viable xenograft alternative, necessitating further long-term studies to confirm its efficacy. The study was registered in the Chinese Clinical Trial Registry (http://www.chictr.org.cn/) with the registration number ChiCTR2100042060. This clinical trial was not registered before participant recruitment or randomization.

Purpose: This study evaluated the effects of screw preload loss on three implant systems, both in silico and in vitro.

Methods: Three finite element analysis (FEA) models of implant restorations were created using bone-level (BL, 4.8×12 mm; BLX, 4.5×12 mm) and tissue-level (TL, 4.8×12 mm) implant systems. The screws in each group were subjected to preloads of 100 N and 200 N, with an additional 130 N load applied to the crown tops. An in vitro study of the principal strain was conducted using digital image correlation (DIC) under the same conditions as for the FEA models. The results were evaluated for von Mises stress, principal strain, and sensitivity index.

Results: During loading, the highest stress levels were observed in the implants and screws. In the BL group, the screws experienced the highest von Mises stress at 466.04 MPa and 795.26 MPa in the 100 N and 200 N groups, respectively. The BLX group showed the highest von Mises stress at 439.33 MPa and 780.88 MPa in the implants in the 100 N and 200 N groups. Sensitivity analysis revealed that the screws and abutments in the TL group were significantly more affected by the preload changes.

Conclusions: The abutment in the TL group was particularly sensitive to preload changes compared with those in the BL and BLX groups. Variations in the preload significantly affect the stress distribution in implants and screws. Maintaining screw preload stability under loading is crucial in clinical practice to prevent mechanical failure.

Purpose: Although the association between oral health and physical frailty is well established, psychological frailty has not been investigated. Therefore, this prospective cohort study was conducted to examine the association between masticatory performance and psychological frailty in older community-dwelling Japanese individuals.

Methods: The participants included 498 older adults who completed baseline and 3- and 6-year follow-up surveys. The World Health Organization-5 (WHO-5) scale and the Japanese version of the Montreal Cognitive Assessment (MoCA-J) were used to evaluate the psychological frailty status of participants. Psychological frailty was defined as a WHO-5 score < 13 and a MoCA-J score < 23. Masticatory performance was evaluated using a scoring method for the test gummy jelly (score: 0–9). A mixed-effects ordinal logit model analysis was used to examine the influence of masticatory performance and number of teeth on the development of psychological frailty while adjusting for relevant factors such as educational level, financial status, living situation, area of residence, history of chronic diseases, and handgrip strength.

Results: A total of 311 participants (62.5%) exhibited psychological robustness at baseline. The rates of development of psychological frailty after 3 and 6 years were 4.2% and 4.5%, respectively. The longitudinal analysis revealed that masticatory performance at baseline was negatively associated with the prevalence of psychological frailty and pre-frailty at follow-up.

Conclusions: Decreased masticatory performance is associated with the development of psychological frailty in older community-dwelling people of Japanese descent.

Patient: A 67-year-old woman presented to our clinic with chief complaints of headache and mandibular heaviness. Physical examination revealed bilateral tenderness in the temporalis and masseter muscles, corresponding to the patient’s chief complaint. Thus, a diagnosis of temporomandibular disorders (TMDs)-related headache was made. However, sleep disorders were identified after further consultation. Hence, sleep apnea-related headache was suspected due to a snoring habit with a Mallampati classification of Class IV. Out-of-center sleep testing (OCST) revealed a respiratory event index (REI) of 10.1/h and a low peripheral oxygen saturation (SpO₂) of 76%. Consequently, a diagnosis of obstructive sleep apnea (OSA) was made, and treatment using the mandibular advancement device (MAD) was recommended. Following MAD treatment, the patient’s sleep quality improved, and morning headaches ceased. Subsequent OCST performed while wearing the MAD showed a significant reduction in the REI to 1.6/h and an increase in the SpO₂ to 86%, indicating the therapeutic efficacy of the MAD in treating OSA.

Discussion: MAD treatment effectively alleviated the patient’s morning headaches, suggesting that sleep bruxism should not be considered the only cause of headaches. OSA should also be considered and addressed when investigating the potential causes of morning headaches in patients.

Conclusions: In patients experiencing TMDs symptoms and morning headaches, TMDs should not be presumed as the sole cause. Dentists should discuss the likelihood of sleep disorders during consultations. If sleep disorders are suspected, the possibility of OSA should be considered, and sleep tests should be conducted when necessary.

Patients: A case series of five patients (mean age, 77.0 years) with complaints of nocturnal xerostomia were subjected to occlusal appliance treatment with a reservoir of moisturizing gel during the night. An occlusal appliance covers the dental arch and hard palate, providing space in the midline of the hard palate to hold the moisturizing gel. Sleepiness was assessed using the Epworth Sleepiness Scale (ESS), and sleep quality was assessed using the Japanese version of the Pittsburgh Sleep Questionnaire (PSQI-J) before and after treatment. The total PSQI-J scores decreased in all patients after treatment. The ESS score, sleep time, and sleep efficiency improved or remained unchanged and none of the patients’ symptoms worsened.

Discussion: This study demonstrated the efficacy of occlusal appliance treatment in patients with dry mouth in improving self-reported sleep quality. Patients included those with nocturnal xerostomia and poor sleep quality on the PSQI-J. Treatment with xerostomia resulted in improved sleep quality, as assessed by the decrease in PSQI-J scores.

Conclusions: This case series suggests that sleep quality may be worse in patients with xerostomia, and that treatment for nocturnal xerostomia using occlusal appliances may improve sleep quality.