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1.  Interradicular trabecular bone density of the lateral maxilla for temporary anchorage devices – a histomorphometric study 
Head & Face Medicine  2015;11(1):1.
To analyze the interradicular trabecular bone density of the lateral maxilla regarding the insertion of temporary anchorage devices (TADs).
Material and methods
The material consisted of tissue blocks of autopsy material from 20 subjects (17 male, 3 female, 16 - 63y). The specimens comprised the dentated alveolar bone of the lateral maxilla. The interradicular areas (IRA) from canine to distally of the second molar (IRA 3–4, 4–5, 5–6, 6–7, 7d) were histomorphometrically measured with respect to the hard tissue fraction of the trabecular bone (HTFTB, %) and statistically analyzed.
Histomorphometric measurements showed the following results: Mean HTFTB of IRA 3–4 was 44.08%, of IRA 4–5 31.07%, of IRA 5–6 33.96%, of IRA 6–7 36.33% and of IRA 7d 25.40%. Only the difference between the HTFTB of IRA 3–4 and the other IRAs was statistically significant (p < 0.05). Regarding the minimum and maximum HTFTB value of each IRA, there was a great amount of difference, especially for IRA 3–4: minimum HTFTB was 17.20% and maximum 67.03%.
Apart from the IRA between canine and first premolar, the HTFTB in the IRAs of the lateral maxilla have to be classified as low or even moderate. IRA 3–4 should also be considered cautious regarding its minimum values. Thus, it seems that the interradicular trabecular bone density of the lateral maxilla is unfavorable to achieve a good primary stability of TADs.
PMCID: PMC4326331
Orthodontic; Anchorage; Implant; Insertion site; Failure rate; Bone density
2.  Angular photogrammetric analysis of the soft tissue profile in 12-year-old southern Chinese 
Head & Face Medicine  2014;10(1):56.
To quantify average angular measurements that define the soft tissue profiles of 12-year-old southern Chinese and to determine gender differences.
Materials and methods
A random population sample of 514 12-year-old children was recruited (about 10% of a Hong Kong Chinese birth cohort). Photographs were taken in natural head posture and 12 soft tissue landmarks were located on the photos to measure 12 angular measurements using ImageJ (V1.45s) for Windows. Approximately 10% of photographs were reanalyzed and method error was calculated. Angular norm values for the 12 parameters were determined and gender differences were assessed using 2 sample T-test with 95% confidence interval.
The response rate was 54.1% (278/514). Norm values for the 12 angular measurements were generated. The greatest variability was found for the nasolabial (Cm-Sn-Ls) and labiomental (Li-Sm-Pg) angles. Gender differences were found in 4 angular parameters: vertical nasal angle (N-Prn/TV) (p < 0.05), cervicomental angle (G-Pg/C-Me) (p < 0.001), facial convexity angle (G-Sn-Pg) (p < 0.01) and total facial convexity angle (G-Prn-Pg)(p < 0.01).
Norm values for 12 angular measurements among 12-year-old southern Chinese children were provided and some variability noted. Gender differences were apparent in several angular measurements. This study has implications in developing norm values for southern Chinese and for comparison with other ethnic groups.
PMCID: PMC4298958  PMID: 25540054
Photogrammetric analysis; Soft tissue profile; 12-year-old southern Chinese
3.  Human oral cells’ response to different endodontic restorative materials: an in vitro study 
Head & Face Medicine  2014;10(1):55.
The aim of this study was to compare the biological interaction of human osteoblasts and cells of the human periodontal ligament (PDL) with different endodontic restorative material as Mineral Trioxide Aggregate (MTA), Biodentine, amalgam and composite over a time period of 20 days.
Materials and methods
Human PDL cells and osteoblasts were harvested, cultured and according to standardized protocols. The cell populations were characterized with the corresponding surface markers following standardized procedures. The specimens were produced with special regard to constant dimensions and volume in the different groups. Cell attachment and proliferation were evaluated morphologically after Richardson staining and cell count was performed after 1d, 8d, 13d and 20d. All experiments were performed in triplets. The results were statistically analyzed using the ANOVA- and Tukey-test (p < 0.05).
Morphological analysis proved good proliferation and cell attachment in both cements. A remarkable result was the organized spreading and parallel alignment of the PDL cells in contact with MTA and especially Biodentine (cells maturing in a second cell layer crossway to the first one). From 8d onward Biodentine showed the highest quantity of PDL cells (p < 0.05). Biodentine and MTA resulted in a significantly higher cell density in osteoblast and PDL cell culture. The other groups showed a lower PDL cell density from 8d and a lower osteoblast cell density from 13d when compared to control and cement samples (p < 0.05).
MTA and Biodentine showed a good biocompatibility in contact with the human osteoblasts and cells of the periodontal ligament. Regarding cell survival and proliferation particularly of PDL cells Biodentine showed good results and can be considered as a well-tolerated bioactive endodontic material.
Electronic supplementary material
The online version of this article (doi:10.1186/s13005-014-0055-4) contains supplementary material, which is available to authorized users.
PMCID: PMC4298870  PMID: 25533283
Amalgam; Biodentine; Composite resin; Mineral Trioxide Aggregate; Osteoblasts; Periodontal ligament cells
4.  Accuracy of electronic apex locators to detect root canal perforations with inserted metallic posts: an ex vivo study 
Head & Face Medicine  2014;10(1):57.
The detection of possible root canal perforations caused during a metal post placement is frequently difficult to diagnose. The aim of this study was to investigate the accuracy of apex locators to diagnose such perforations.
Materials and methods
Thirty mesiolingual root canals of extracted mandibular molars were instrumented (30/.04) and a post space was prepared. A root canal perforation was intentionally made at the bi-furcation (n = 15). Metal posts were cemented in 15 perforated and 15 non-perforated root canals. The teeth roots were embedded in an agar-agar solution. The resulting measurements (“short” or “beyond” the apex) disclosed if a perforation could be identified with five different apex locators (ProPex II, Elements Apex Locator, Apex NRG, Raypex 5 and Raypex 6). The sensitivity and specificity (95% interval confidence) were calculated.
All devices excluded the absence of perforations (100% with 95% confidence interval [78%; 100%] specificity). The Apex NRG and Raypex 6 detected all perforations (100% with 95% confidence interval [78%; 100%] sensitivity). The ProPex II, Elements Apex Locator, and Raypex 5 detected 14 out of 15 perforations (93% with 95% confidence interval [68%; 100%] sensitivity).
All devices determined root canal perforations, due to metallic posts, within clinical acceptable ranges.
PMCID: PMC4311483  PMID: 25533476
Root perforation; Metal post; Diagnosis; Apex locators
5.  Surgery first – indications, protocols, results 
Head & Face Medicine  2014;10(Suppl 1):O1.
PMCID: PMC4304405  PMID: 25559319
6.  Experience with orthodontic temporary anchorage devices 
Head & Face Medicine  2014;10(Suppl 1):O10.
PMCID: PMC4304407
9.  Surgery first – protocols and techniques for orthodontic treatment 
Head & Face Medicine  2014;10(Suppl 1):O2.
PMCID: PMC4304413
11.  Segmented therapy in surgery 
Head & Face Medicine  2014;10(Suppl 1):O4.
PMCID: PMC4304416
12.  Segmented therapies in orthodontics 
Head & Face Medicine  2014;10(Suppl 1):O5.
PMCID: PMC4304428
13.  Chin wing osteotomy - a new facial concept 
Head & Face Medicine  2014;10(Suppl 1):O6.
PMCID: PMC4304429
14.  3D image superimpositions for orthodontic diagnostics and therapy 
Head & Face Medicine  2014;10(Suppl 1):O7.
PMCID: PMC4304432
17.  A comparison of mandibular and maxillary alveolar osteogenesis over six weeks: a radiological examination 
Head & Face Medicine  2014;10(1):50.
Insufficient information exists on comparing radiological differences in bone density of the regeneration rate in the alveolar bone of the maxilla and mandible following the creation of similar defects in both.
Alveolar bone defects were created from five healthy Chacma baboons. Standardized x-ray images were acquired over time and the densities of the selected defect areas were measured pre-operatively, directly post-operatively and at three- and six weeks post-operatively. Differences in densities were statistically tested using ANOVA.
The maxilla was significantly more radiologically dense (p = 0.026) than the mandible pre- operatively. No differences were obtained between the maxilla and mandible directly postoperatively and three- and six weeks post-operatively respectively; i.e. densities were not significantly different at the different time points after the defects had been created (three weeks: t = 1.08, p = 0.30; six weeks: t = 1.35, p = 0.19; three to six weeks: t = 1.20, p =0.25). The increase in density in the mandible was 106% (8.9 ± 7.6%/time versus 4.3 ± 2.7%/time) over three weeks, 28% (15.0 ± 8.1%/time versus 11.7 ± 8.0%/time) over six weeks and 56% (12.5 ± 9.7%/time versus 8.0 ± 6.9%/time) over three-to-six weeks and was higher than in the maxilla over the same intervals.
Radiological examination with its standardized gray-scale analysis can be used to determine the difference in bone density of the maxilla and mandible. Although not statistically significant, the mandible healed at a faster rate than the maxilla, especially observed during the first three weeks after the defects were created.
PMCID: PMC4289173  PMID: 25429901
Regeneration; Alveolar bone; Radiological; Gray-scale
18.  Lingual orthodontic treatment duration: performance of two different completely customized multi-bracket appliances (Incognito and WIN) in groups with different treatment complexities 
Head & Face Medicine  2014;10(1):46.
The occurrence of side-effects of fixed orthodontic therapy, such as white-spot lesions and root resorption, are known to be significantly more frequent with increasing duration of treatment. Multi-bracket treatment should be as short as possible, in order to minimize the risks of collateral damage to teeth. The aim of this non-randomized clinical trial was to compare treatment duration with each of two types of customized lingual orthodontic appliances (Incognito, 3 M-Unitek; WIN, DW LingualSystems), taking into account treatment complexity. The null-hypothesis was that there would be no significant difference in active orthodontic treatment duration between them.
Of 402 potentially eligible participants, a population sample of n = 376 subjects (nIncognito = 220; nWIN = 156; m/f 172/204; mean age ± SD 17.3 ± 7.7Y) treated in one orthodontic center (Bad Essen, Germany) with completely customized lingual appliances in upper and lower permanent dental arches was recruited with the inclusion criterion of initiated and completed lingual multi-bracket treatment within the assessment period of April 1st 2010 – Nov 30, 2013, and the exclusion criterion of less than 24 bracketed teeth. We used four-factorial ANOVA to assess the impact of the following factors: initial degree of severity of malocclusion (mild to moderate, S1; severe, S2), appliance type (Incognito; WIN), sex, and age group (<=16; >16 Y) on the duration of lingual multi-bracket treatment.
Overall, mean treatment duration was 21.7 (SD 7.2) months, which was significantly shorter for WIN for both sub-groups of treatment complexity (S1: 17.96 mo; S2: 20.49 mo) compared to Incognito (S1: 22.7 mo; S2: 29.79 mo). ANOVA revealed a significant influence of the main effects ‘appliance type’, and ‘severity’, independent of each other. Therefore, the null-hypothesis was rejected.
In terms of treatment duration, the WIN appliance performed significantly better than the Incognito appliance. Consequently, subjects treated with the WIN appliance are expected to be exposed to lower risks of the typical side-effects associated with longer multi-bracket treatment durations, such as root resorption and enamel decalcification.
PMCID: PMC4228173  PMID: 25361639
Orthodontic treatment duration; Lingual multibracket appliance; Incognito appliance; WIN appliance; In vivo
19.  Mandibular reconstruction using plates prebent to fit rapid prototyping 3-dimensional printing models ameliorates contour deformity 
Head & Face Medicine  2014;10(1):45.
Recently, medical rapid prototyping (MRP) models, fabricated with computer-aided design and computer-aided manufacture (CAD/CAM) techniques, have been applied to reconstructive surgery in the treatment of head and neck cancers. Here, we tested the use of preoperatively manufactured reconstruction plates, which were produced using MRP models. The clinical efficacy and esthetic outcome of using these products in mandibular reconstruction was evaluated.
A series of 28 patients with malignant oral tumors underwent unilateral segmental resection of the mandible and simultaneous mandibular reconstruction. Twelve patients were treated with prebent reconstruction plates that were molded to MRP mandibular models designed with CAD/CAM techniques and fabricated on a combined powder bed and inkjet head three-dimensional printer. The remaining 16 patients were treated using conventional reconstruction methods. The surgical and esthetic outcomes of the two groups were compared by imaging analysis using post-operative panoramic tomography.
The mandibular symmetry in patients receiving the MRP-model-based prebent plates was significantly better than that in patients receiving conventional reconstructive surgery.
Patients with head and neck cancer undergoing reconstructive surgery using a prebent reconstruction plate fabricated according to an MRP mandibular model showed improved mandibular contour compared to patients undergoing conventional mandibular reconstruction. Thus, use of this new technology for mandibular reconstruction results in an improved esthetic outcome with the potential for improved quality of life for patients.
PMCID: PMC4213462  PMID: 25338640
Medical rapid prototyping; Three-dimensional printing model; Surgical reconstruction; Mandible; Head and neck cancer
20.  Frontalis suspension surgery to treat patients with essential blepharospasm and apraxia of eyelid opening-technique and results 
Head & Face Medicine  2014;10(1):44.
We describe the results of 15 patients suffering from essential blepharospasm with apraxia of eyelid opening who underwent frontalis suspension surgery.
Material and methods
Patients with apraxia of eyelid opening and unresponsive to botulinum toxin injections were studied. Bilateral frontalis suspension surgery was performed (sling operation) using polytetrafluoroethylene (Gore-Tex®) sutures. The patients reported the degree of improvement using a subjective rating scale to evaluate the benefit of the operation at two times after surgery (0-10 days and 180-360 days).
The patients reported a high degree of subjective improvement. In the early postoperative period (0-10 days) the mean degree of subjective improvement was 74.6% (standard deviation (SD) 26.4%). At 180-360 days after surgery the mean improvement was 70.0% (SD 26.7%). Small hematomas of the upper lid occurred postoperatively in all patients. Other complications were suture extrusions (9.1%), suture granulomas (6.1%), lacrimation (5.0%) and local infections (7.5%). Postoperatively, all patients needed additional botulinum toxin injections for optimal outcome.
Frontalis suspension surgery is a minimally invasive and effective treatment option for apraxia of eyelid opening in patients with essential blepharospasm unresponsive to botulinum toxin injections alone.
PMCID: PMC4213496  PMID: 25338619
Blepharospasm; Apraxia of eye lid opening; Frontalis suspension surgery
21.  Microbial contamination of toothbrushes during treatment with multibracket appliances 
Head & Face Medicine  2014;10(1):43.
It was aimed to assess the retention of caries-associated microorganisms on two different manual toothbrushes (conventional and tapered) and to evaluate the influence of multibracket appliances (MB) on the microbial contamination of the brush head.
50 MB-patients and 50 subjects without MB received a toothbrush (elmex® interX medium short head or meridol®) plus toothpaste (elmex®) for exclusive use and an information sheet with standardised brushing instructions. After 14 days of regular tooth brushing, the brushes were collected and sluiced in Sputasol solution. The suspension was incubated on selective agar plates and the amount of Streptococcus mutans, lactobacilli and Candida albicans for each brush head was assessed.
Regarding the retention of microorganisms, no differences could be detected between the two bristle designs. However, the amount of S. mutans was significantly higher on brushes used by MB-patients (p < 0.005) than on the brushes of subjects without MB. The number of Lactobacilli and C. albicans was minimal in all cases and below statistical evaluation.
During treatment with MB appliances, toothbrushes were contaminated more intensely with S. mutans independent of bristle design. A more frequent replacement of toothbrushes may thus be recommended for patients undergoing MB-treatment.
PMCID: PMC4197314  PMID: 25301033
Microbial contamination; Toothbrush design; Multibracket therapy
22.  Efficiency of pivot splints as jaw exercise apparatus in combination with stabilization splints in anterior disc displacement without reduction: a retrospective study 
Head & Face Medicine  2014;10(1):42.
To evaluate efficiency of pivot splints in jaw exercises, in combination with stabilization splints, in cases of anterior disc displacement without reduction of temporomandibular joint.
Subjects and methods
Twenty-three patients who referred to the prosthodontics clinic in 1995–1997 were included in the study, where anterior disc displacement without reduction of temporomandibular joint was diagnosed using magnetic resonance imaging and clinical examination. Pivot splints were used for jaw exercises for five minutes long; five times/day and stabilization splints were used at all other times. The patients were followed for 24 weeks. Lateral and protrusive excursions along with maximum mouth opening and were evaluated at each control. Bilateral palpation of temporal, masseter, sternocleidomastoid muscles and TMJ was assessed for pain perception before and after treatment. Data were statistically analyzed using Paired sample t-test and Independent Samples t-test (p < .05).
Mean mandibular range of motion measurements increased from 28.74 mm prior to 49.17 mm on maximum opening; right/left lateral excursion from 7.61 mm to 12.04 mm and 4.09 mm to 7.3 mm on protrusion after treatment. All changes observed before and after treatment were found to be statistically significant. (p < .001) Pain symptoms were eliminated at the end of 24 weeks of treatment in all patients.
Using pivot splints as an exercise regimen along with a stabilization splint may be a viable treatment option for patients with anterior disc displacement without reduction; as normal mandibular range of motion was established and pain was eliminated.
PMCID: PMC4197281  PMID: 25300939
Temporomandibular joint; Internal derangement; Anterior disc displacement without reduction; Magnetic resonance imaging; Pivot splint; Stabilization splint
23.  Ectopic thyroid papillary carcinoma of nasopharynx associated with adenoid hypertrophy: an unusual presentation 
Head & Face Medicine  2014;10(1):40.
Ectopic thyroid tissue of nasopharynx is an uncommon phenomenon and papillary thyroid carcinoma arising from the tissue is extremely rare. The authors report a rare case of 16-year-old girl with papillary thyroid carcinoma of nasopharynx. Clinicians were ever confused by adenoid hypertrophy and solved the diagnostic dilemma by adequate examinations. In the case, we mainly emphasize that surgeons should be aware of and actively consider such a possibility of ectopic papillary thyroid carcinoma of nasopharynx in children and adolescents with long-term nasal obstruction, even if thyroid carcinoma is a rare tumor.
PMCID: PMC4176853  PMID: 25238975
Ectopic thyroid papillary carcinoma; Nasopharynx; Adenoid hypertrophy; Nasal obstruction
24.  Stability of treatment with self-ligating brackets and conventional brackets in adolescents: a long-term follow-up retrospective study 
Head & Face Medicine  2014;10(1):41.
The aim of this study was to assess the long-term stability of treatment with self-ligating brackets compared with conventional brackets.
Materials and methods
The long-term follow-up retrospective study sample consisted of two groups of patients: group SL (including passive and interactive self ligating braces) comprised 30 subjects treated with self-ligating brackets at a mean pretreatment (T0) age of 13.56 years, with a mean follow up period for 7.24 years; group CL comprised 30 subjects treated with conventional brackets at a mean pretreatment age of 13.48 years, with a mean follow up period for 7.68 years. Relapse were evaluated by dental casts examination using the Peer Assessment Rating (PAR) index and the Little irregularity index. The two groups were evaluated for differences in the changing of PAR and Little irregularity index using paired-t tests. Inter-observer and intra-observer reliability was assessed by means of the Pearson’s correlation coefficients method.
There were no significant differences changed in PAR and the Little irregularity index between groups for the long-term follow-up period.
The study revealed that brackets type did not affect the long-term stability. Considering self-ligating brackets were expensive, given comprehensive consideration for the patients to choose suitable orthodontic bracket type was of critical importance.
PMCID: PMC4179858  PMID: 25239092
Self-ligating brackets; Conventional brackets; Stability
25.  Influence of E-smoking liquids on human periodontal ligament fibroblasts 
Head & Face Medicine  2014;10:39.
Over the last years, electronic cigarettes (ECs) have become more popular, particularly in individuals who want to give up smoking tobacco. The aim of the present study was to assess the influence of the different e-smoking liquids on the viability and proliferation of human periodontal ligament fibroblasts.
Method and materials
For this study six test solutions with components from ECs were selected: lime-, hazelnut- and menthol-flavored liquids, nicotine, propylene glycol, and PBS as control group. The fibroblasts were incubated up to 96 h with the different liquids, and cell viability was measured by using the PrestoBlue® reagent, the ATP detection and the migration assay. Fluorescence staining was carried out to visualize cell growth and morphology. Data were statistically analyzed by two-tailed one-way ANOVA.
The cell viability assay showed that the proliferation rates of the cells incubated with nicotine or the various flavored liquids of the e-cigarettes were reduced in comparison to the controls, though not all reductions were statistically significant. After an incubation of 96 h with the menthol-flavored liquid the fibroblasts were statistically significant reduced (p < 0.001). Similar results were found for the detection of ATP in fibroblasts; the incubation with menthol-flavored liquids (p < 0.001) led to a statistically significant reduction. The cell visualization tests confirmed these findings.
Within its limits, the present in vitro study demonstrated that menthol additives of e-smoking have a harmful effect on human periodontal ligament fibroblasts. This might indicate that menthol additives should be avoided for e-cigarettes.
PMCID: PMC4237808  PMID: 25224853
Cell proliferation; Electronic cigarettes; Fibroblasts; In vitro; Menthol; Nicotine

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