Does the great auricular nerve predict the size of the maintrunk of the facial nerve? A clinical and cadaveric study

There seems to be only individual clinical experience and some anecdotal evidence about a relation between the width of the great auricular nerve (GAN) and the size of the main trunk of the facial nerve during parotidectomy. To our knowledge no anatomical studies have been published. In this cadaveric and clinical study we measured the widest point of the GAN as it crosses the sternomastoid muscle before it divides, and the main trunk of the facial nerve before it bifurcates. Measurements were obtained from 16 patients who required formal superficial parotidectomies with identification of the facial nerve, and from 21 cadavers (16 formalin-fixed and 5 fresh frozen) where both sides were dissected. We recorded the results and the side of dissection. The mean (SD) width of the GAN and facial nerve from all the dissections was 2.75 (0.53) mm and 2.83 (0.54) mm, respectively. There was a strong correlation between the width of the nerves from both sides (left: r = 0.934, p < 0.001; right: r = 0.940, p < 0.001). The nerves did not differ significantly in size in patients or cadavers (GAN: right, p = 0.873; left, p = 0.486; facial nerve: right, p = 0.931; left, p = 0.691). We have found that the GAN accurately predicts the width of the main trunk of the facial nerve. This is particularly useful surgically as a narrow GAN can alert the surgeon to expect a small facial nerve.     

Is there a relationship between dental crowding and the size of the maxillary or mandibular apical base?

Objective:To determine whether apical base size is related to dental crowding.Materials and Methods:Digital scans of dental casts were taken of 75 untreated Class I adults to measure maxillary and mandibular tooth size, dental arch perimeters, intermolar widths, and intercanine widths. Cone beam computed tomography (CBCT) images were used to measure the apical base of the maxilla and mandible, including the total cross-sectional area, five basal arch perimeters and five basal arch widths. Principal components factor analyses were performed to evaluate the relationships between the apical base size and tooth-size-arch-length discrepancies (TSALD).Results:The dental arch and maxillary apical base measures were significantly larger in males than females. There were only limited sex differences in mandibular apical base size. The dental arch measurements were smaller in subjects with greater upper and lower TSALD. Maxillary and mandibular apical base dimensions were positively interrelated. Low-to-moderate correlations were found between the size of the maxillary apical base and TSALD. The size of the mandibular apical base was not related to upper or lower TSALD. Tooth size showed little to no relationship with TSALD.Conclusions:Although maxillary apical base size is related to maxillary and mandibular crowding in subjects with Class I malocclusion, mandibular apical base size is not.     

How does fluoride concentration in the tooth affect apatite crystal size?

Despite fluoride's (F) well-documented ability to prevent caries, the effects of F concentrations on enamel and dentin apatite crystals are unknown. The present study examined the hypothesis that tooth F concentration and tooth crystallite size correlate. One hundred human unerupted third molars were studied-53 from Fortaleza-Brazil (F water 0.7 ppm), 23 from Toronto (1.0 ppm), and 24 from Montreal (0.2 ppm). F concentration was analyzed by Neutron Activation Analysis and apatite crystal size by powder x-ray diffraction. A positive correlation between dentin F concentration and enamel crystallite length and width was found. Enamel crystallite length was significantly greater in teeth from Fortaleza than in teeth from Toronto (p = 0.011) and Montreal (p = 0.003). Enamel crystallite widths were significantly greater in Fortaleza teeth compared with those from Toronto (p = 0.020) and Montreal (p < 0.001). No difference in the dentin crystallite size was seen in the 3 regions. Thus, tooth F concentration and crystallite size correlate.     

What is the relation between the presence of caries in the deciduous dentition and the chronology of the eruption of the permanent teeth?

Based on data obtained from a prospective epidemiological study in a random sample of 4468 Flemish children, accurate emergence ages for permanent teeth could be established. When data on permanent tooth emergence in different populations are compared, differences are most pronounced for premolars. Several authors hypothesised that this difference could be explained by a difference in caries experience in the primary molars. The purpose of this study was to quantify the effect of caries experience in a primary molar on the timing of emergence of its successor. The results indicate that the emergence of the premolars was accelerated by 2 to 8 months when its predecessor had been decayed and or filled but had not been extracted. Premature loss of maxillary primary molars resulted in a significant acceleration of the emergence of the premolars; this was not observed in the mandible. In conclusion, when considering permanent tooth emergence ages, caries experience in the primary dentition should be taken into account.     

Influence of the site of origin on the outcome of squamous cell carcinoma of the maxilla—oral versus sinus

The maxilla may be affected by squamous cell carcinoma (SCC) from both oral and sinus sites. We sought to determine whether the site of origin of the maxillary tumour, oral as compared to sinus, influences survival. Univariate Kaplan–Meier and multivariate Cox proportional hazard models analysis of 58 patients with SCC involving the maxilla, treated with curative intent, was conducted. The overall 5-year disease-free survival for the group was 41.7%. Five-year disease-free survival for oral subsite SCC was 56.8%, while for sinus subsite was only 21.6%. Univariate analysis found SCC of sinus origin to be associated with a poorer prognosis, however this was not confirmed on multivariate analysis. T-stage and positive margins were found to be the only independent risk factors. For SCC of the maxilla, sinus origin of the tumour per se does not confer a poorer prognosis; however, as a result of the complex anatomy of the midface, these tumours can present at an advanced stage, while surgical control of the disease can be more difficult, especially posteriorly. Tumour size and positive margins were the determinants of a poor prognosis in this group of patients with maxillary SCC.     

An evaluation of slot size in orthodontic brackets--are standards as expected?

The slots of five upper left central incisor brackets from 11 commercially available bracket systems (3M Unitek, Monrovia, Calif: Twin Torque Roth, Clarity MBT, and Victory Series MBT; Dentarum, Pforzheim, Germany: Discovery Roth (0.56 mm) and Elegance Plastic Roth; Forestadent, Pforzheim, Germany: Mini Mono MBT; TP LaPorte, Indiana: Nu-Edge Roth and Mxi Advant-Edge Roth; Ormco Corp., Orange, Calif: Damon II SL Roth; Ortho Organizers, San Marcos, Calif: Elite Mini Opti-MIM Roth and Elite Mini Opti-MIM MBT) were measured in the 0.022-inch (0.5588 mm) dimension. Measurements were taken after operator calibration, and a digital readout was produced. Results indicate that all bracket slots are oversized. Three bracket systems slots (Twin Torque, Clarity, and Mini Mono) were within 5% (+/-1.08, 1.655, 1.75) of their stated dimensions with essentially parallel slot walls. The Elegance Plastic slot was parallel sided but oversized by 12% (+/-1.15). The geometry of bracket slots was also variable. The Victory Series slot was slightly divergent with the top oversized by 6% (+/-1.035). The Nu-Edge slot was divergent and slot top oversized by 14% (+/-1.32). The Mxi Advant-Edge, Damon II SL, Elite Mini Opti-MIM Roth, and MBT were all convergent, and the base of the Damon slot was oversized by 17% (+/-1.79). The Discovery bracket was convergent, and the slot base was oversized by 24% (+/-1.255), which was the largest recorded variance. This bracket also had a 7% difference between the widths of the slot top and the base. Inaccurate machining of bracket slot dimensions and the use of undersized archwires may directly and adversely affect three-dimensional tooth positioning.     

Validation of the Spanish version of the “Questionnaire on the treatment of approximal and occlusal caries”

Objectives

To translate and validate a Spanish version of the “Questionnaire on the treatment of approximal and occlusal caries” as a method of collecting information about treatment decisions on caries management in Chilean primary health care services.

Materials and methods

The original questionnaire proposed by Espelid et al. was translated into Spanish using the forward–backward translation technique. Subsequently, validation of the Spanish version was undertaken. Data were collected from two separate samples; first, from 132 Spanish-speaking dentists recruited from primary health care services and second, from 21 individuals characterised as cariologists. Internal consistency was evaluated by the generation of Cronbach's alpha, test–retest reliability was evaluated by Cohen's kappa, convergent validity was evaluated by comparing the total scale scores to a global evaluation of treatment trends and discriminant validity was evaluated by investigating the differences in total scale scores between the Spanish-speaking dentist and cariologist samples.

Results

Cronbach's alpha indicated an internal consistency of 0.63 for the entire scale. Cohen's kappa correlation coefficient expressed a test–retest reliability of 0.83. Convergent validity determined a Pearson's correlation coefficient of 0.24 (p?<?0.01). The comparison of proportions (chi-squared) indicated that discriminant validity was statistically significant (p?<?0.01), using a one-tailed test.

Conclusions

The Spanish version of the “Questionnaire on the treatment of approximal and occlusal caries” is a valid and reliable instrument for collecting information regarding treatment decisions in cariology.

Clinical relevance

The clinical relevance of this study is to acquire a reliable instrument that allows for the determination of treatment decisions in Spanish-speaking dentists.     

Review on 209 Congenital Cysts of the Floor of the Mouth

目的：比较1980—2005年在武汉大学口腔医院治疗的89位中国病人和在约旦医院治疗的120位病人三型口底囊肿的临床特点。方法：回顾性分析皮样囊肿、表皮样囊肿和畸胎样囊肿患者的年龄、性别、种族，以及比较两组患者的囊肿位置、大小、就诊时间、手术治疗方法和复发率等方面的差别。结果：209例口底囊肿中，93例（44．5％）男性，116例（55．5％）女性。皮样囊肿66例（31．6％）、表皮样囊肿115例（55％）、畸胎样囊肿28例（13．4％）。皮样囊肿、表皮样囊肿多见于头3个10岁年龄组，20-29岁高发，而畸胎样囊肿高好发于10岁以前。约90％的患者无自觉症状。发病后6个月以内就诊者，第1组（43．8％）明显少于第2组（80％）。这些先天性囊肿常发生在口底中部。就诊时第1组中囊肿直径大于3cm者达48．3％，而第2组中囊肿直径大于3cm者仅11．7％。第1组中经口外进路切除病变占58．4％，而第2组为41．7％。141例随访病例的术后复发25例，复发率是17．7％。结论：两组口底囊肿有类似的临床特点，其中表皮样囊肿较常见，畸胎样囊肿的发病年龄较小。手术切除不彻底可导致病变复发。     

Consideration of effect of the amount of mandibular setback on the submental region in the planning of orthodontic–orthognathic treatment

Aesthetic outcome has gained in importance in the treatment of patients with orthognathic problems. Historically, Class III malocclusions have historically been treated by isolated mandibular setback and maxillary advancement, whereas bimaxillary procedures have recently become the more common option. Functional outcome and stability have been discussed previously. The aim of this observational study was to evaluate the effect of mandibular setback (BSSO) on the cervical region. We studied 38 Class III patients (20 women and 18 men, mean (SD) age 25 (0.8) years) who we identified from our clinical records and who were treated between 1 January 2002 and 30 December2012 with mandibular setback procedures and followed up for 6 months. To study the effect of the amount of mandibular setback on the aesthetic outcome we have distinguished between patients with less than 5 mm setback and those with 5 mm or more. In patients whose mandibular setback was less than 5 mm there was no significant change in cervical length. However, it decreased significantly in patients in whom the movement was 5 mm or more. Postoperatively the lip–chin–throat angle (p = 0.02), the length of the lower lip (p = 0.002), and the length of the upper lip (p = 0.003) from the aesthetic line also differed significantly between the 2 groups. Our observations strongly suggest that all these relations should be considered when treatment is being planned to avoid an unpleasant aesthetic impact on the chin region.     

What are the limitations of the non-patient-specific implant in titanium reconstruction of the orbit?

There is ongoing discussion about patient-specific implants (PSI) to reconstruct orbital defects. Although PSI offer excellent clinical outcome, they are expensive. Subsequently, their routine application is not indicated. The purpose of this study was to estimate the frequency of implant malposition and revision procedures after primary orbital repair with preformed plates and to identify cases where primary use of PSI would help to prevent revision surgery. All patients included in the study were operated on for orbital fractures at the Royal London Hospital between August 2017 and July 2018. Selection criteria included adult patients treated for orbital fractures with a titanium plate. Revision was planned in symptomatic patients presenting with clear implant malposition. Seventy-nine patients with 81 implants were included, 33 of whom had multiple orbital wall fractures (medial wall and floor or all four walls) and were summarised as group 2. Group 1 consisted of single orbital floor/medial wall fractures. The five patients for whom revision surgery was planned or undertaken because of radiological poorly positioned implants and substantial clinical symptoms all had multiple wall fractures. This finding was significant (p = 0.006). The major reason for revision was a defect that was too large for the prescribed plate. Patients with large orbital defects needing surgical treatment are at risk of implant malposition. The orbital reconstruction with preformed plate evidences good outcome in single wall fractures. However, the risk of malposition increases massively with fracture size. We therefore postulate that in large, two-wall fractures, primary treatment with a PSI has to be considered.     

Filler size of resin-composites, percentage of voids and fracture toughness: is there a correlation?

The objective of this study was to investigate the correlation between filler size, fracture toughness and voids. Seven model resin composites and one commercial have been used in the study. A single edge notch mould was used to prepare samples (n=8). A selected area of 1mm below and above the notch was scanned with micro CT and then the percentage of voids calculated. A universal testing machine was used to measure fracture toughness. Percentage of voids and fracture toughness data were analysed using ANOVA and post hoc methods were performed to check any significant differences between materials tested (p<0.05). Conclusion: Filler size is strongly correlated to % voids but has no effect on fracture toughness.     

In vivo effects of geranylgeraniol on the development of bisphosphonate-related osteonecrosis of the jaws

Background

Bisphosphonate-related osteonecrosis of the jaws (BRONJ) is a complication of the bisphosphonate (BP) treatment and its pathopysiology is still not fully understood. The existing preventive and treatment options require updates and more attention. Geranylgeraniol (GGOH) so far demonstrated an increased activity and viability of the cells previously treated with zoledronic acid (ZA). The aim of this study was to evaluate the in vivo effects of GGOH on the development of BRONJ.

What is the purpose of launching the World Journal of Stomatology?

Congratulations to the publisher, members of the editorial board of the journal, all the authors and readers for launching the World Journal of Stomatology (WJS) as a new member of the World series journal family! Significant scientific advances and important breakthroughs need to be published to impact dental care and reach an audience of researchers and clinicians who can create more effective dental treatments for their patients. There is a need to share scientific information, methodologies, therapies, and hypotheses related to stomatology, through an open-access format, to reach the widest possible audience. The WJS was created to fulfill the role of disseminating the most significant, innovative and transformational cutting edge research in dentistry. The WJS is a peer-reviewed open-access periodical centered in stomatology, with a multidisciplinary coverage that will publish high-impact articles in all areas of the dental clinical specialties, applied science, epidemiology, trauma and dental care, dental materials, oral biology and microbiology. The WJS is not scared of controversy or challenges to existing doctrine, since they are supported by high-quality science or unequivocal clinical outcomes. The WJS will avoid publishing confirmatory and low-impact articles. The WJS will only publish articles directly relevant to stomatology and dentistry because this is what our readers expect. If you need to share any exciting dental research discoveries and reach the widest possible audience, you will find in the WJS the most helpful resource to publish your papers!     

Does the procedure of arthrography affect the range of movement in patients with locking of the temporomandibular joint?

The aim of this study was to investigate whether arthrography itself altered the range of mandibular movements, in a group of patients with locking of the temporomandibular joint (TMJ). The clinical records of a series of 161 patients who were diagnosed with locking of the TMJ were retrospectively analysed. Mouth opening had improved in 57 out of 161 patients (35%). Twenty-three patients (14%) had improved by 5 mm or less. Nineteen patients (11%) had improved by more than 5 mm but less than 10 mm, whereas 15 patients (9%) had improved by more than 10 mm. Of the patients who experienced an improved mouth opening, only nine (15%) had improved from their pre-arthrography restricted maximum opening to beyond the lower limit of normal. This suggests that the injection of contrast medium had an effect on the range of vertical opening in patients with displacement of the disc without reduction.     

A clinical investigation of the relationship between the quality of conventional complete dentures and the patients’ quality of life

Objective

The purpose of this study was to determine whether there is a correlation between the clinical quality of conventional complete dentures and patient quality of life.

Materials and methods

This study included a random sample of 32 completely edentulous patients (15 males and 17 females) who were treated with conventional complete dentures. Using a validated questionnaire, three investigators evaluated the dentures independently on the basis of seven clinical parameters: esthetics (lip support and lower lip line), retention and stability of the maxillary and the mandibular dentures, and occlusion. Patients completed the validated Oral Health Impact Profile-20 (OHIP-20) questionnaire. Correlations were determined by using the point-biserial correlation coefficient.

Results

Clinicians rated the overall clinical quality of the dentures satisfactory in 80.3% of patients. The mean (±standard deviation) total OHIP-20 score was 56.3 ± 15.9 out of a possible 120 maximum. A statistically significant negative correlation was found between the stability of the maxillary and mandibular dentures and the total OHIP-20 score (p = 0.009 and 0.0023, respectively). A negative correlation between the total OHIP-20 score and the retention of the mandibular denture approached significance (p = 0.092). Esthetics, retention of the maxillary denture, and occlusion were not correlated with patient quality of life (p > 0.169).

Conclusion

Stability of the maxillary and mandibular dentures is the denture quality parameter that can most significantly affect patient quality of life.     

A study on the fit of the base plate —Influence of canditions of storage—

The aims of this study was to define the effect of storage conditions of base plates, which consist of self-curing resin. Examinantions were made on the dimensional accuracy with the passage of time of base plate stored in water and air on a plaster model for standerdized maxillary edentulous. The following conclusions were obtained;