The prognostic value of histopathology on lingual nerve neurosensory recovery after micro-neurosurgery

Objective

Micro-neurosurgical repair is considered in permanent nerve damage but the outcome is unpredictable. We examined if histopathologic parameters of traumatic neuromas have a prognostic value for recovery in relation to lingual nerve micro-neurosurgery.

Materials and methods

Retrospective case study on neurosensory recovery after micro-neurosurgery. Outcome variables were as follows: pain perception, two-point discrimination, and sum score of perception, before and 12 months after micro-neurosurgery. Predictive histopathology variables included size, nerve tissue, and inflammation. Statistics are as follows: logistic and correlation analyses (P < 0.05).

Results

Sixty-five patients with lingual nerve damage were included in the study. Improved two-point discrimination was associated with small size of resected tissue (P = 0.0275). No normal appearing distal nerve tissue was associated with improved sum score of perception (P = 0.0185), higher final sum score of perception value (P = 0.0475) and final pain perception (P = 0.0324). Foreign body reaction was associated with no final pain perception (P = 0.0492).

Conclusions

Small size, absence of distal nerve tissue, and no foreign body reaction were associated with improvement of the neurosensory functions.

Clinical relevance

Histological parameters of the traumatic neuromas in routine preparation appeared to have some prognostic value for neurosensory functions as improvement of the neurosensory functions was associated with small size of resected tissue, no distal normal appearing nerve tissue, and no foreign body reaction.

     

Malocclusion in the primary dentition in children with and without deformational plagiocephaly

Objectives

Asymmetries of the jaw and orthodontic abnormalities are suspected as long-term consequences of positional cranial deformity. But only few data exist on this issue. As plagiocephaly is a common problem in infancy, potential functional impairments should be investigated to initiate appropriate measures if necessary. The aim of our study was to compare the orthodontic situation in primary dentition of children with positional plagiocephaly and children without cranial deformities.

Material and methods

Fifty children treated by helmet therapy for plagiocephaly and 50 non-affected children (age 1.98–5.69 years) were examined in a cross-sectional study. Orthodontic parameters of all dimensions were assessed and analyzed.

Results

Children of the plagiocephalic group showed more often orthodontic alterations compared to the others. Especially the frequencies of a class II malocclusion (36 vs. 14 %), an edge-to edge bite (28 vs. 12 %), and deviations of the midline (38 vs. 16 %) were conspicuous. However, none of the differences was significant (p > 0.003). Of all observed mandibular asymmetries, 69 % appeared as a shift to the contralateral side of the former flattened occipital region.

Conclusion

Positional head deformity might be associated in some cases with a higher prevalence of occlusal abnormalities in primary dentition.

Clinical relevance

Positional plagiocephaly interfaces medicine and dentistry. As it is a common disorder, this etiology has to be considered in the prevention and therapy of malocclusion.

     

Association of vdr,cyp27b1, cyp24a1 and mthfr gene polymorphisms with oral lichen planus risk

Objectives

The current study investigated the association between VDR EcoRV (rs4516035), FokI (rs2228570), ApaI (rs7975232) and TaqI (rs731236), CYP27B1 (rs4646536), CYP24A1 (rs2296241), and MTHFR (rs1801133) gene polymorphisms and risk of oral lichen planus (OLP) occurrence.

Materials and methods

The study group consisted of 65 oral lichen planus patients and 100 healthy blood donors in the control group. Single nucleotide polymorphisms were genotyped by real time PCR or PCR-restriction fragment length polymorphism (RFLP) method.

Results

Heterozygous as well as mutated genotype of vitamin D receptor (VDR) FokI (rs2228570) polymorphism was associated with increased oral lichen planus risk in comparison with wild type genotype (odds ratio (OR) = 3.877, p = 0.017, OR = 38.153, p = 0.001, respectively). A significantly decreased OLP risk was observed for heterozygous genotype of rs2296241 polymorphism in CYP24A1 gene compared with the wild type form (OR = 0.314, p = 0.012). VDR gene polymorphisms ApaI and TaqI were in linkage disequilibrium (D’ = 0.71, r ² = 0.22). Identified haplotype AT was associated with decreased OLP risk (OR = 0.592, p = 0.047).

Conclusion

Our results highlight the possible important role of VDR FokI (rs2228570) and CYP24A1 rs2296241 gene polymorphisms for oral lichen planus susceptibility.

Clinical relevance

Identification of new molecular biomarkers could potentially contribute to determination of individuals with OLP predisposition.

     

Influence of the bleaching interval on the luminosity of long-term discolored enamel-dentin discs

Objectives

The aim of this study is to investigate the influence of changing the sodium perborate-tetrahydrate (PBS-4) at a 4-day interval versus no change after 16 days of internal bleaching.

Materials and methods

Two hundred and ten bovine enamel-dentin discs were discolored for 3.5 years with 14 different endodontic materials. All groups with a discoloring index of ?E _(mean) ≥ 5.5 were included in the present investigation: ApexCal (APCA), MTA white + blood (WMTA+BL), Portland cement + blood (PC+BL), blood (BL), MTA gray (GMTA), MTA gray + blood (GMTA+BL), Ledermix (LED), and triple antibiotic paste containing minocycline (3Mix). Fourteen specimens of each group were randomly assigned into two treatment groups: (1) no change of the PBS-4 (n = 7); (2) change of the PBS-4 every 4 days (n = 7). Color measurements were taken at 10 different time intervals and the L*a*b* values were recorded with a spectrophotometer (VITA Easyshade® compact).

Results

In the group 3Mix, significantly better results were achieved by changing the bleaching agent every 4 days (P = 0.0049; q = 0.04), while the group WMTA+BL indicated better results by no change of the bleaching agent (P = 0.0222, q = 0.09). All remaining groups showed no statistical difference between the two treatment procedures.

Conclusions

Moderate discolorations can be successfully treated without changing the bleaching agent over a period of 16 days. Changing the sodium perborate-tetrahydrate every 4 days is preferred in case of severe discolored enamel-dentin discs only.

Clinical relevance

This approach may offer a reduced number of clinical appointments and a secondary cost reduction to the patient.

     

Anatomical relation between nasal septum deviation and oropharynx volume in different facial patterns evaluated through cone beam computed tomography

Introduction

The objective of this study was to establish the anatomical relation between nasal septum deviation (NSD) and oropharynx volume in different facial patterns using cone beam computed tomography (CBCT).

Methods

Ninety CBCT examinations were analyzed. InVivoDental software was used to evaluate cephalometric image reconstructions in terms of facial type, determined from cephalometric measurements indicative of growth direction; the presence of NSD was also evaluated. ITK-SNAP software was employed for delimitation of the oropharynx. Intra-examiner error methods were recorded. The results were subjected to parametric and non-parametric tests using Bioestat 5.0.

Results

A comparison of facial types revealed a significantly lower prevalence of NSD in the dolichofacial group compared with the brachyfacial and mesofacial groups (P = 0.0101 and 0.0149, respectively). In the total sample, there was a very strong positive relation between the presence of NSD and oropharynx space volume (P = 0.0162). The oropharynx volume was larger in all facial patterns in the presence of NSD.

Conclusion

The presence of NSD was not associated with facial type, although the oropharynx volume in patients with NSD increased. Therefore, deviation of the septum influences oropharynx volume.

     

Early<Emphasis>-</Emphasis>life factors affect risk of pain and fever in infants during teething periods

Aim

This longitudinal study aimed to investigate the prevalence of teething-related pain and fever and the early-life factors that may affect the risk of experiencing these disturbances within the first 1.5 years of life.

Materials and methods

Participants were recruited (n = 1033) through the Growing Up in Singapore Towards healthy Outcomes (GUSTO) birth cohort (n = 1237). Interviews were performed tri-monthly regarding the prevalence of teething pain and fever in children from 6 to 18 months of age. Crude and multivariable analyses were conducted using Poisson-log regression models.

Results

Prevalence rates for teething pain and fever were 35.5 and 49.9 % respectively. Multivariable Poisson regression analysis showed maternal second-hand tobacco smoke (SHS) exposure to increase the risk of both pain (mean ratio = 1.35; p = 0.006) and fever (mean ratio = 1.22; p = 0.025), whereas SHS exposure plus active smoking further increased risk of teething pain in the children (mean ratio = 1.89; p = 0.029). Delivery via Caesarean section increased risk of teething pain (mean ratio = 1.27; p = 0.033), while prenatal plasma vitamin D insufficiency lowered such a risk (mean ratio = 0.62; p = 0.012). Compared to Chinese infants, Indian babies exhibited lower risk of teething pain and fever (both p ≤ 0.001).

Conclusions

Early-life factors such as tobacco smoke exposure and vitamin insufficiency during pregnancy, ethnicity and childbirth via Caesarean section may significantly affect the child’s susceptibility to teething-related pain and fever.

Clinical relevance

Knowledge of prevalence and risk factors of teething disturbances may better equip primary caregivers and healthcare professionals to accurately detect teething-related local and/or systemic signs/symptoms and effectively facilitate tobacco cessation among pregnant women.

     

Implant placement under existing removable dental prostheses and its effect on masticatory performance

Objective

The aim of this within-subject study was to evaluate the outcome with implant-tooth-supported removable partial dental prostheses (RPDP group) and implant-supported removable complete dental prostheses (edentulous group) in terms of masticatory performance and self-assessment.

Materials and methods

Thirty patients participated in this prospective clinical study (RPDP group: n = 12; edentulous group: n = 18). The prostheses were supported in strategically advantageous regions by placing implants with ball attachments and corresponding matrices in the existing dentures. The masticatory performance was evaluated with the Swallowing Threshold Test Index (STTI), the number of chewing strokes, and the time needed until swallowing at pre-treatment and 6 weeks after integration of ball attachments. Additionally, patients scored chewing satisfaction before and after implantation on a visual analogue scale.

Results

The STTI increased significantly (p ≤ 0.05) after implant therapy in the edentulous group but not in the RPDP group. Furthermore, the STTI was significantly higher (p ≤ 0.05) in the RPDP group than in the edentulous group at pre-treatment, however, not after therapy (P > 0.05). All patients were very satisfied after therapy concerning ability of speaking, chewing, and stability of their prosthesis.

Conclusions

Patients of the edentulous group benefit more from strategically placed implants under the existing dentures than patients from the RPDP group. However, according to the subjective assessment, the chewing satisfaction generally increased for both groups after implant therapy.

Clinical relevance

Patients with a strongly reduced dentition and edentulous patients benefit from strategically placed implants under the existing removable dentures.

     

Silver diamine fluoride and glass ionomer differentially remineralize early caries lesions,in situ

Objectives

The aim of the present study was to evaluate the percent mean mineral density (MD) change of early caries lesions after the application of silver diamine fluoride (SDF) or glass ionomer cement (GIC).

Materials and methods

This double-blind, crossover study involved two experimental phases of 28 days each. Thirty-two pairs of enamel slabs were created from the proximal surfaces of 16 premolars. Each pair of artificial carious slabs was randomly divided into the control or test group (38 % SDF or GIC). The slabs were attached to orthodontic brackets and bonded to the maxillary first permanent molars of 16 subjects for 28 days. After a 7-day washout period between phases, the subjects received the other material for the second phase. The mean MD of the lesions was measured by microcomputed tomography.

Results

SDF yielded a percent mean MD increase at a depth of 0–84 μm, although increase in the GIC group was observed at a depth of 24–108 μm. The percent mean MD changes of the SDF and GIC groups were similar (p?=?0.100) and significantly higher than in control (p?<?0.001, p?=?0.003, respectively).

Conclusions

The two materials increased the percent mean MD change of early proximal caries lesions to a similar extent, but with different spatial patterns.

Clinical relevance

Due to deeper level of GIC remineralization, the refractive index of the GIC applied enamel might be closer to sound enamel. Hence, GIC is recommended for remineralization of anterior teeth. SDF staining makes it unsuitable for use in anterior teeth; thus, it is reserved for use in posterior teeth.

     

Osteosarcomas of the Head and Neck Region: A Case Series with a Review of Literature

Background

Osteosarcomas of head and neck region have unique biology and exhibit a clinical behavior and natural history that is distinct from osteosarcomas of the trunk and extremities. Our understanding of this malignant bone tumor is largely based on data from single institutions or compiled from registries, and hence the clinical practice guidelines seem confusing and conflicting.

Aims and Objectives

To analyze the demographic profile, disease characteristics and survival outcomes of osteosarcoma of head and neck region.

Materials and Methods

Retrospective analysis of the patients treated for osteosarcoma of head and neck region with curative intent in the period between the years 2001–2013 at a tertiary cancer center from South India.

Results

A total of 14 patients were treated in the said period with a mean age of 37 years. The most common site was mandible (n = 9 patients) followed by maxilla (n = 4) and paranasal sinuses (n = 1). Conventional osteoblastic variant of OS was the most common histological variant (n = 8) followed by the chondroblastic variant (n = 5). The median disease-free survival was 41.7 months, whereas the median overall survival of our patient cohort was 47.6 months. A formal analysis of various prognostic factors showed only postoperative margin positivity to be the single important factor affecting the survival outcomes.

Conclusion

Head and neck osteosarcoma that most commonly afflicts the jaw bones occurs in the fourth decade of life. Despite being a small series, our study does highlight the importance of achieving a margin-negative resection as a part of the multimodality treatment of head and neck osteosarcomas. Considering the relative paucity of data, there is a need for multi-institutional collaborative studies to refine the therapeutic strategies for the management of patients with head and neck osteosarcomas.

     

Increased local recurrence in advanced parotid malignancy treated with mastoidectomy without lateral temporal bone resection

Objective

We analyzed patients with advanced parotid malignancy requiring proximal facial nerve exposure undergoing mastoidectomy versus lateral temporal bone resection to determine differences in local and distant recurrence.

Study design

The study design is a case series with chart review.

Setting

The setting is in Tertiary care practice in Fort Worth, Texas from January1998 to January 2014.

Subjects and methods

The study included 120 patients with advanced parotid malignancy, 82 males between 19 and 87 years, and 38 females between 26 and 83 years. Patients with no overt bone involvement were treated with parotidectomy and mastoidectomy for exposure of the proximal facial nerve, and patients with clinically suspected (radiographic imaging or clinical fixation) bone involvement were treated with parotidectomy and lateral temporal bone resection. Follow up ranged from a minimum of 18 months to 11 years following surgery.

Results

Sixty patients were treated with mastoidectomy and 60 were treated with lateral temporal bone resection. In patients treated with mastoidectomy, 13 had local recurrence and 7 had distal recurrence. In patients treated with lateral temporal bone resection, 2 had local recurrence while 9 had distant recurrence. Statistical analysis revealed that patients treated with mastoidectomy developed local recurrence (p = 0.0022) more commonly than those treated with lateral temporal bone resection. There was no significant difference in distant recurrence between both groups (p = 0.5949).

Conclusions

Patients with advanced parotid malignancy should be treated aggressively with parotidectomy and lateral temporal bone resection regardless of bone involvement due to increased risk of local recurrence in those treated with mastoidectomy alone.

Level of evidence

Level of evidence is a 4 case series.

     

Citrullination in the periodontium—a possible link between periodontitis and rheumatoid arthritis

Objectives

The aim of the present study was to assess human and bacterial peptidylarginine deiminase (PAD) activity in the gingival crevicular fluid (GCF) in the context of serum levels of antibodies against citrullinated epitopes in rheumatoid arthritis and periodontitis.

Materials and methods

Human PAD and Porphyromonas gingivalis-derived enzyme (PPAD) activities were measured in the GCF of 52 rheumatoid arthritis (RA) patients (48 with periodontitis and 4 without) and 44 non-RA controls (28 with periodontitis and 16 without). Serum antibodies against citrullinated epitopes were measured by ELISA. Bacteria being associated with periodontitis were determined by nucleic-acid-based methods.

Results

Citrullination was present in 26 (50 %) RA patients and 23 (48 %) controls. PAD and PPAD activities were detected in 36 (69 %) and 30 (58 %) RA patients, respectively, and in 30 (68 %) and 21 (50 %) controls, respectively. PPAD activity was higher in RA and non-RA patients with periodontitis than in those without (p = 0.038; p = 0.004), and was detected in 35 of 59 P. gingivalis-positive samples, and in 16 of 37 P. gingivalis-negative samples in association with high antibody levels against that species.

Conclusions

PAD and PPAD activities within the periodontium are elevated in RA and non-RA patients with periodontitis. PPAD secreted by P. gingivalis residing in epithelial cells may exert its citrullinating activity in distant regions of the periodontium or even distant tissues.

Clinical relevance

In periodontitis, the citrullination of proteins/peptides by human and bacterial peptidylarginine deiminases may generate antibodies after breaching immunotolerance in susceptible individuals.

     

Was molar incisor hypomineralisation (MIH) present in archaeological case series?

Objective

With respect to the unknown aetiology of molar incisor hypomineralisation (MIH), it is unclear whether this phenomenon was overlooked in the last century as a result of a high number of caries in children or if this developmental disorder was not present until then. Therefore, this study determined the presence of MIH in historical dentitions and teeth.

Materials and methods

Dental remains from late medieval (n = 191, twelfth–sixteenth century, Regensburg, Germany), post-medieval (n = 33, sixteenth–eighteenth century, Passau, Germany) and modern age archaeological skeletal series (n = 99, nineteenth–twentieth century, Altdorf, Germany) were examined for MIH. In addition, linear enamel hypoplasia (LEH), diffuse opacities, hypoplasia and Turner’s teeth were documented.

Results

MIH-related demarcated opacities or enamel breakdowns were found in only 15 (0.4 %) of the 3891 examined permanent teeth. Ten cases (3.1 %) from a total of 323 dentitions were classified as having MIH. In contrast, 98 individuals (30.3 %) showed LEH. Other enamel disorders were recorded in 64 individuals (19.8 %).

Conclusion

With respect to the low number of affected dentitions and teeth, MIH most likely did not exist or was at least rarely present in the investigated archaeological case series.

Clinical relevance

This study supports the hypothesis that MIH may be linked to contemporary living conditions or other health-related factors.

     

Internal derangement in the temporomandibular joint of juveniles with clinical signs of TMD

Aim

The aim of this study was to investigate possible correlation of specific skeletal or dental class in children and adolescents with clinical signs of temporomandibular dysfunction (TMD) with the severity of internal derangement (ID) of the temporomandibular joint.

Materials and methods

Based on MRI images, the ID of 232 juvenile temporomandibular joints in 116 patients were retrospectively recorded. The distribution of the ID stages within the skeletal and dental classes was compared by means of the χ ² test.

Results

Excluding the comparison between skeletal Class I (S I) and skeletal Class II (S II; p < 0.05), no statistically significant differences in the distribution of the ID stages were found between the skeletal classes (p > 0.05). No statistically significant differences were found when comparing the distribution of the ID stages between the dental classes (p > 0.05).

Conclusion

According to these findings, there is no skeletal or dental class that is related to higher degrees of internal derangement in the TMJs of children and adolescents presenting clinical signs of TMD. Therefore, it is not possible to draw conclusions about the severity of the ID in relation to the dental and skeletal class in symptomatic juvenile TMJs.

     

Characterization and Antibiotic Sensitivity Profile of Bacteria in Orofacial Abscesses of Odontogenic Origin

Background

Odontogenic infections range from peripheral abscess to superficial and deep infections leading to severe infections in head and neck region. This study was aimed to assess bacterial isolates responsible for orofacial infection of odontogenic origin and their drug susceptibility patterns so as to provide better perceptive for the management of odontogenic infections.

Methods

The study was made in a selected cohort of patients, irrespective of age and gender having moderate and severe orofacial infections of odontogenic origin admitted to Yenepoya University Hospital. Pus samples were collected and identification of bacteria was performed by 16S rRNA gene sequencing. Antimicrobial susceptibility testing was performed by Kirby-Bauer disc diffusion method.

Result

A total of 37 study subjects were included, with bacterial isolation rate of 31 (83.7 %). The mean age presented of all patients was 40.62. Of all, 24 (64.9 %) were males. Staphylococcus aureus, Enterobacter claocae subsp. dissolvens, Klebsiella quasipneumoniae subsp. similipneumoniae, Staphylococcus aureus subsp. anaerobius and Klebsiella pneumoniae subsp. ozaenae were the most prevalent isolates. Result showed that 58.6 % of the isolates were resistant to gentamicin, 52.5 % for ampicillin, 51.3 % for piperacillin; least resistant being 18.9 % for azithromycin.

Conclusion

High prevalence of bacterial isolates was found, Staphylococcus aureus being the dominant. Most of the bacteria were resistant to different classes of antibiotics. Appropriate antibiotics should be given based on the bacterial isolates, culture sensitivity and clinical course of the disease.

     

Postural assessment in class III patients before and after orthognathic surgery

Purpose

This study aimed to assess body posture before and after bimaxillary orthognathic surgery by photogrammetry in skeletal class III patients.

Methods

Thirty-one patients with skeletal class III dentofacial deformities (14 men, 17 women) who underwent orthodontic preparation for surgery were included in this non-randomized controlled trial. Of these, 15 who did not undergo orthognathic surgery during the period of this study served as controls. Postural assessment was performed by photogrammetry using SAPO® (Postural Assessment Software) based on anterior-, posterior-, and lateral-view images taken 1 month before and 4 months after bimaxillary orthognathic surgery with internal rigid fixation (or 4 months after the initial assessment, for the control group). The study was approved by PUCRS Research Ethics Committee, and written informed consent was obtained from all individual participants prior to their inclusion in the study.

Results

There was no significant difference between groups for age, gender, and GAP. In the intervention group, the right leg/hindfoot angle, which initially indicated a valgus deformity, normalized after intervention (P?<?0.048). Posterior displacement of the head (P?<?0.005) and trunk (P?<?0.004) were observed after intervention.

Conclusions

These results suggest that correction of class III dentofacial deformities by bimaxillary orthognathic surgery can produce systemic postural adjustments, especially posterior displacement of the head and trunk and knee and ankle valgus.

     

Long-Term Effect of Maxillary Distraction Osteogenesis (DO) on Nasal Index in Adult Patients with Cleft Lip and Palate Deformities

Purpose

To test the hypothesis that there is no immediate and long-term effects of maxillary distraction osteogenesis (DO) on nasal index among adult subjects with cleft lip and palate deformities.

Materials and Methods

Twelve adult subjects in the age range of 17–20 years with complete unilateral cleft lip and palate underwent advancement of maxilla by DO. The immediate and long-term effects of maxillary DO on nasal index were evaluated from extra-oral full face frontal photographs recorded prior to DO (T₀), at the end of active DO (T₁) and at least 2-years after the DO (T₂). The ANOVA, Post Hoc test (Bonferroni) and Pearson correlation coefficients were used. The probability value (P value) 0.05 was considered as statistically significant.

Results

SNM angle and Ptm-M distance increased significantly by DO (P < 0.001). The nasal index increased significantly (P < 0.01) by 13.85 % from T₀ value of 85.15 ± 4.49 to 99.02 ± 11.16 % at the end of active distraction (T₁) and by 12.69 to 97.84 ± 9.14 % at the end of long-term follow-up (T₂). The correlation between sagittal maxillary advancement and nasal index was statistically significant (P < 0.001). For each millimeter of maxillary advancement, the nasal index increased by 1.38 % and 1.8 % at the end of active distraction and long-term follow-up respectively.

Conclusion

The advancement of maxilla by distraction osteogenesis among subjects with cleft lip and palate deformities increased nasal index significantly.

     

Comparison of two electronic apex locators on human cadavers

Objective

The aim of this study on human cadavers was to compare the accuracy of two electronic apex locators (EALs) Dentaport ZX (J. Morita Corporation, Tokyo, Japan) and Raypex 6 (VDW, Munich, Germany).

Materials and methods

Twenty-two single rooted teeth of four human cadaver heads were scheduled for this study. Before the extraction, an access cavity was opened and the crown was cut to establish a stable reference point for all measurements. The working length determination was performed with Dentaport ZX and Raypex 6 in the presence or not of 5.25 % sodium hypochlorite (SH) using a k-file 10. The teeth were then extracted and the real working length (RWL) was measured under a stereomicroscope at ×30 magnification. The difference between the two working lengths was calculated: positive values indicate measurements exceeding the foramen, while negative values indicated measurements short of the foramen. The data were analyzed with a t test analysis.

Results

The mean of distances was 0.33 ± 0.20 mm and 0.32 ± 0.2 mm for Dentaport ZX respectively in the presence or not of SH and 0.38 ± 0.20 mm and 0.39 ± 0.19 mm for Raypex 6. No statistical differences were found between the two devices (p > 0.05).

Conclusions

Both apex locators showed a high accuracy in the presence or not of SH.

Clinical relevance

Both electronic apex locators can be recommended for clinical use and their accuracy is not affected by SH.

     

Electronic central bearing point as registration method in individuals with and without temporomandibular disorders

Objectives

The aim of this study was to examine different central bearing point methods in patients with and without temporomandibular disorders (TMD) by an experienced and unexperienced examiner.

Material and methods

The 20 fully dentulous subjects were screened for TMD based on the Research Diagnostic Criteria for TMD and distinguished into functional impaired and functional healthy groups. The mandibular relationship was recorded by an electronic central bearing tracing device (IPR-System, IPR GmbH, Oldenburg, Germany) with an integrated pressure sensor. Three bite registration methods were performed using this device: initial neuromuscular position, final neuromuscular position after dynamic sequences with the intraoral pin (=neuromuscular deprogramming), and centric relation guided manually by an experienced and an unexperienced examiner.

Results

The neuromuscular positions before and after neuromuscular deprogramming were not significantly different (paired t test as a group comparison test: transverse: p = 0.369; sagittal: p = 0.486). Both positions were significantly anterior in comparison to the manually guided centric relation (paired t test as a group comparison test: p < 0.0001). The neuromuscular positions before and after deprogramming tend to have high scattering values.

Conclusion

By means of the central bearing point method, the manually guided centric relation is the one which is sufficiently reproducible. It seems doubtful to take the significant anterior neuromuscular position for a definite reconstruction.

Clinical relevance

Using the central bearing point method, the manually guided centric relation should be preferred, whereas the neuromuscular position should not be used for definite reconstructions.

     

Cold plasma: a novel approach to treat infected dentin—a combined ex vivo and in vitro study

Objectives

The aim of this study was to evaluate the antimicrobial effect of cold plasma (CP) on infected dentin surfaces in vitro and ex vivo.

Materials and methods

To examine the effect of cold plasma on root surfaces, 24 root surfaces were infected with Streptococcus mitis. Specimens were randomly divided into three groups: Within the control group (C), root surfaces were rinsed with NaCl; root surfaces in the second group were additionally scaled and root planed (SRP), and in the third group, root surfaces were rinsed, scaled, root planed, and in addition, CP was applied (SRP + CP). To examine the effect of CP on root caries lesions (RCLs), 16 freshly extracted teeth with symmetrical carious lesions were equally divided into two groups. In the control group, carious lesions were treated with chlorhexidine (CHX), whereas CHX was applied in conjunction with CP in the test group (CHX + CP). For microbiological analysis, dentin samples were serially diluted and CFU counts were estimated after 24 h of incubation.

Results

Compared to C, mean CFU values for SRP and SRP + CP were significantly lower (p < 0.05). In addition, mean CFUs for SRP + CP were reduced to 0 and, therefore, significantly lower than SRP (2.98 log CFU/mL) alone (p = 0.000, Mann-Whitney U). Regarding RCLs, significantly lower mean CFU values were observed for CHX + CP when compared to CHX (4.45 vs. 2.67 log CFU/mL, p = 0.002, Mann-Whitney U test).

Conclusions

For disinfection of exposed root surfaces, the adjunctive application of CP is promising. In addition, the combined application of CHX + CP has the potential to disinfect root dentin surfaces.

Clinical relevance

It was shown that the combination of cold plasma with CHX is the best available option for the disinfection of root surfaces.