Adenine nucleotide changes in submandibular salivary glands of rats following isoproterenol or incisor tooth amputation

Male rats (180-220 g) were injected daily with isoproterenol (2 mg/kg of body weight) for up to 6 days, or their incisor teeth were amputated on every other day for up to six amputations. The animals were subdivided into groups killed 12 or 24 h after the first or last intervention. In the development of sialadenosis caused by isoproterenol, the levels of ATP were greater (13-30%), while those of AMP were lower (13-19%) in the experimental groups. No variation was noted in ADP content. In tooth-amputated animals, only the five and six amputation subgroups showed higher values for ATP (approx. 17%), and ADP (12 and 15%, respectively). The inorganic phosphate level was lower in both experimental groups (between 11-28% for isoproterenol and 13-22% for amputation). Thus isoproterenol caused different metabolic responses in submandibular salivary glands from those induced by incisor amputation.     

Fixed orthodontic appliances cause pain and disturbance in somatosensory function

This study aimed to assess the short‐term effects of orthodontic pain on quantitative sensory testing (QST) in subjects receiving fixed orthodontic treatment. Twenty patients and 12 healthy volunteers (as controls) participated. All 20 patients had bonded AO self‐ligating brackets, with a 0.014 super elastic nickel‐titanium arch wire placed in the brackets. Pain [self‐reported on a visual analog scale (VAS)], and thermal and mechanical thresholds, were tested at six time points – before (baseline), and 2 h, 24 h, 7 d, 14 d, and 30 d after, force application – in the treatment group. The attached gingiva adjacent to the left upper central incisor (21 gingiva) was hypersensitive to cold stimuli (i.e. increased cold detection thresholds were detected) in the treatment group. The pressure pain thresholds of the left upper central incisor (21) and 21 gingiva were significantly reduced. Our results suggest clear signs of sensitization of the trigeminal nociceptive system up to 1 month after force application and orthodontic pain. Quantitative assessment of somatosensory function may help to provide a better understanding and profiling of the underlying neurobiological mechanisms related to orthodontic pain.     

Isoproterenol-induced changes in glutathione metabolism in the rat parotid gland

Rat parotid glands were removed at timed intervals after intraperitoneal injection of isoproterenol (IPR). Reduced/oxidized glutathione ratios, glutathione peroxidase, glutathione reductase and amylase activities were determined. Parotid gland amylase content fell to less than 5 per cent of control values within 1 h after IPR, then slowly returned to control levels by 24 h. The ratio of reduced/oxidized glutathione was decreased at 2 h after IPR injection, returned to near control values at 6 h, then increased above control levels at 9, 12 and 24 h. Glutathione peroxidase activity was increased only at 12 h after injection of IPR, whereas glutathione reductase activity initially decreased, then reached peak values at 12 h. These results indicate that alterations in metabolic activity during the secretory cycle are accompanied by changes in the reduced/oxidized glutathione ratio and the activity of glutathione-metabolizing enzymes. Cellular events contributing to these alterations in glutathione metabolism may include exocytosis, endocytosis and membrane recycling, increased amino-acid transport and resynthesis of secretory proteins.     

Changes in mitotic activity in the basal proliferative tissues after experimental shortening of the rat incisor

Mitotic counts in defined areas increased significantly at 6 h after shortening of the incisor in the labial pulp and the lingual periodontium, and at 12 h in all tissues examined including the internal enamel epithelium and the lingual pulp. Mean values were also greater 18 and 24 h after shortening of the incisor in all tissues. It is deduced that elimination of occlusal contacts caused immediate stimulation of the cell division cycle as well as acceleration of incisor eruption. Circadian rhythm of the mitotic activity in the basal proliferative tissues was not marked.     

Dental implant treatment for two adjacent missing teeth in the maxillary aesthetic zone: a comparative pilot study and test of principle

Aim: The aim of this prospective comparative pilot study was to evaluate hard and soft peri‐implant tissues in patients with a missing adjacent central and lateral upper incisor treated with either one implant and an implant crown with a cantilever or two implants with solitary implant crowns up to 1 year after functional loading. Material and methods: In the “Implant–cantilever group”, five patients were treated with one dental implant in the region of the central incisor (NobelReplace Groovy Regular Platform). In the “Implant–implant group”, five patients were treated with two adjacent dental implants: at the position of the central incisor (NobelReplace Groovy Regular Platform) and at the position of the lateral incisor (NobelReplace Groovy Narrow Platform). Implant survival, pocket probing depth, papilla index, marginal bone level and patient satisfaction were assessed during a 1‐year follow‐up period. Results: No implants were lost during the 1‐year follow‐up. Mean pocket probing values of the implants were comparable between the two groups. Papilla index scores in both groups were relatively low, pointing towards a compromised papilla. Marginal bone loss was minimal and comparable between the groups. Patient satisfaction was very high in both groups. Conclusion: In this 1‐year prospective comparative study, no large differences in hard‐ and soft‐tissue levels could be shown between patients with a missing central and lateral upper incisor treated with either one implant and an implant crown with a cantilever or two implants with solitary implant crowns. To cite this article:
Tymstra N, Raghoebar GM, Vissink A, Meijer HJA. Dental implant treatment for two adjacent missing teeth in the maxillary aesthetic zone: a comparative pilot study and test of principle.
Clin. Oral Impl. Res. 22 , 2011; 207–213.
doi: 10.1111/j.1600‐0501.2010.02017.x     

Immediate Osseotite implant placement and immediate loading of a provisional restoration of maxillary lateral incisors

This article describes the immediate replacement of two maxillary lateral incisors teeth after extraction of the left lateral deciduous incisor at the same time with immediate Osseotite implants and immediate restoration. A traumatic dental extraction of a deciduos (b) lateral incisor was performed and a 4mm diameter x 15 mm 3i tapered Osseotite (Implants Innovations, Palm Beach, CA, USA) implant was immediately placed. The other lateral incisor place was treated at the same time and provisional temporary crowns were placed at the same surgery. The provisional crowns did not have any occlusal contact to reduce negative lateral forces. Final impression for definitive restoration was made five months after implant placement veneer ceramic crowns were bonded to the Gingihue abutment (3i, Implants Innovations, Palm Beach, CA) one month later. This article describes the use of immediate implants with immediate loading of Osseotite combined with provisional crowns resulted in an excellent outcome after a two-year follow up period.     

Incisor disocclusion in rats affects mandibular condylar cartilage at the cellular level

The effect of altered occlusion on the mandibular condylar cartilage remains unclear. OBJECTIVE: This study investigated the effect of unilateral incisor disocclusion on cartilage thickness, on mitotic activity and on chondrocytes maturation and differentiation in the mandibular condylar cartilage of rats. DESIGN: The upper and lower left incisors were trimmed 2mm every second day in five rats. In other five rats, the incisor occlusion was not altered. Condylar tissues from both sides of each mandible were processed and stained for Herovici's stain and immunohistochemistry for bromodeoxyuridine (BrdU), transforming growth factor-beta1 (TGF-beta1), alkaline phosphatase (ALP) and osteocalcin (OCN). Measurements of cartilage thickness and the numbers of immunopositive cells for each antibody were analysed by one-way analysis of variance (ANOVA). RESULTS: No significant differences were observed in cartilage thickness after 7 days of unilateral incisor disocclusion. However, the numbers of immunopositive cells for BrdU as a marker of DNA synthesising cells, TGF-beta1 as a marker of chondrocytes differentiation, and ALP and OCN as markers of chondrocytes maturation, were significant higher in the cartilage cells on both sides when incisor occlusion was unilaterally altered. Interestingly, alkaline phosphatase was highly expressed on the condylar side of incisor disocclusion, whereas osteocalcin was highly expressed on the side opposite to the incisor disocclusion. CONCLUSIONS: It is demonstrated that after 7 days, unilateral incisor disocclusion affects the mandibular condylar cartilage at the cellular level by increasing the mitotic activity and by accelerating chondrocytes maturation. Chondrocytes maturation appears more accelerated on the side opposite to incisor disocclusion.     

Pre-autotransplantation alveolar process augmentation and premolar autotransplantation as a treatment method for single tooth replacement in adolescents

The treatment of young patients with missing teeth and an atrophied alveolar process after trauma or agenesis of a tooth can be challenging. The aim of this study was to evaluate autotransplantation of a premolar after pre-autotransplantation alveolar process augmentation (PAPA) as a treatment option for these patients. A retrospective cohort study was implemented to analyse the PAPA procedure and subsequent autotransplantation procedure. Alveolar process augmentation was performed using different types of autologous bone grafts. Subsequent autotransplantation of one or more premolars was performed approximately 4 months later. Nine patients with a mean age of 12 years were included. Twelve premolars were transplanted after a PAPA procedure: seven in the maxillary incisor region, four in the mandibular premolar region, and one in the mandibular incisor region. Initially all transplanted teeth functioned well. However, one mandibular premolar that was transplanted in the maxillary incisor region was lost because of resorption after 6 years of follow-up. The other 11 transplanted teeth functioned well. The mean follow-up was 6 years (range 3–13 years). The results showed that autotransplantation can be facilitated by PAPA with a high chance of success. It can therefore be a valuable addition to other existing treatment options.     

The effects of upper incisor separation on the submandibular and sublingual glands of rats

The effects of upper incisor separation on the submandibular and sublingual glands of rats were examined biochemically, immunohistologically, and radio-immunologically during 28 days of treatment. Lateral separation of the upper incisors by application of force from an orthodontic appliance caused significant enlargement of the sublingual and submandibular glands of rats by three and seven days, respectively, after the beginning of the orthodontic treatment. This enlargement was followed by a significant increase of both RNA and DNA content, with some evidence of hyperplasia and hypertrophy. The enlargement was also associated with a significant increase of substance P at early stages after treatment, suggesting the involvement of the sensory nerves. These changes were largely inhibited by phenoxybenzamine, an alpha-adrenergic blocker, but not by atropine or morphine. Wet weights and RNA contents of the sublingual glands were markedly reduced by atropine. In comparison with control animals, the enlarged submandibular glands of rats subjected to orthodontic treatment secreted additional proteins identical with those secreted by glands enlarged by chronic administration of isoproterenol. In addition, chemical sympathectomy with 6-hydroxydopamine and phenoxybenzamine stimulated the synthesis of these abnormal proteins, but atropine and morphine did not. In contrast, protease activities in the convoluted granular tubule cells in the submandibular glands were increasingly reduced after treatment, as seen in rats subjected to chronic treatment with isoproterenol. However, the submandibular and sublingual glands completely recovered after removal of the orthodontic appliance.     

Planning and control of vertical dimension in Le Fort I osteotomies

Depending on the different anatomy of the soft and hard tissues, concavity or convexity of the face, measurements of inferior or superior repositioning of the maxilla may be less predictable when using only the osteotomy site for this calculation. A more reliable method would be to measure the distance from a bone mark in the forehead to the incisor edges. This method has been practiced by our clinic during the past five years. The method is thought to offer a more accurate estimation of the position of the upper anterior teeth in relation to the lip, although one must anticipate a certain degree of postoperative relapse especially concerning inferior repositioning. In order to evaluate the accuracy of our method, a comparison has been made of the calculated vertical repositioning and the surgical results in two groups. In group I (12 individuals) conventional estimation of maxillary repositioning in the osteotomy line was made; in group II (12 individuals) measurements were made from a bone mark on the forehead to the incisor edges. A satisfying correlation was found between calculated and achieved results in both groups. In comparison between calculated and immediate postoperative measurements the results showed no statistically significant difference between the two methods.     

The thermodynamic behaviour of labial gingiva in patients with destructive periodontal disease

The temperature changes of the labial gingiva and mucosa of the maxillary incisor regions were investigated using computer-assisted thermography. 9 patients with destructive periodontal disease (7 female and 2 male, aged between 12 and 33 years, undergoing periodontal treatment for periods varying from 6 months to 12 years) and 10 volunteers with clinically normal periodontia (6 female and 4 male, aged between 19 and 26 years) took part in this study. The gingivae and mucosae were initially cooled using a homogeneous flow of air (15 l/min at 15 degrees C) for 3 min. 20 s after the cooling phase, temperature increases of these soft tissues were sequentially recorded using 48 thermograms per person. This procedure was repeated 4 times for each person examined. The weighted mean of the time constants of the tissue re-warming curves was significantly higher (p less than 0.025) for the periodontitis group (152 +/- 6 s) compared to the clinically healthy group (110 +/- 9 s). The different thermodynamic behaviour between the 2 groups studied indicated differences in the blood-flow and/or its regulation.     

侵袭性牙周炎患者牙根形态异常的观察

目的 探讨牙根形态异常的评价方法,了解侵袭性牙周炎(aggressive periodontitis,AgP)患者牙根形态异常的分布状况.方法 将108例AgP患者的2841颗牙、41例慢性牙周炎(chronic periodontitis,CP)患者的1135颗牙和30名牙周健康者的840颗牙纳入本项研究,在全口根尖片上根据根宽度参照值并结合牙根外形评定5类牙根形态异常(锥根、细长根、冠根比例失常、弯曲根和后牙融合根).结果 锥根上、下前牙根宽度参照值[分别为(0.04±0.01)、(0.02±0.02)cm]均较正常上、下前牙根宽度参照值[分别为(0.10±0.03)、(0.07±0.02)cm]小,但前者的冠根比大于后者;细长根下前牙的根宽度参照值[(0.02±0.02)cm]、锥根上、下双尖牙的根宽度参照值[分别为(0.03±0.03)、(0.02±0.01)cm]均较相应的正常同名牙[分别为(0.07±0.02)、(0.07±0.01)、(0.18±0.26)cm]小,差异有统计学意义(P＜0.001),但它们的牙根长度与正常牙相比差异无统计学意义(P＞0.05).AgP组根形态异常牙407颗(14.3%)、CP组57颗(5.0%)、健康组31颗(3.7%),各组间差异有统计学意义(P=0.001).结论 AgP患者牙根形态异常的发生率明显高于CP患者和牙周健康者.     

Phosphofructokinase in rabbit dental pulp is less sensitive to ATP inhibition

ATP-dependent profiles of phosphofructokinase (PFK) activity were determined in both crude and Sephadex G-25-filtered fractions from rabbit dental pulp. ATP had a dual effect on PFK as an activator and an inhibitor, according to its concentration. Gel-filtered PFK showed a similar profile to that of crude PFK, indicating a lack of low-molecular-weight effector(s) for PFK in rabbit dental pulp. For complete inhibition of the PFK in rabbit dental pulp, 5 mM ATP was required. This level of ATP is much higher than that required for other typical isozymes of PFK from liver, skeletal muscle or brain. It is postulated that differences in the properties of PFK isozymes are due not only to the subunit structure but also to the presence of other effectors.     

Surface enamel fluoride concentrations of different types of human teeth in a high- and near-optimal-fluoride area

The surface enamel (approximately 4 micron) fluoride concentrations of different tooth types (11, 21, 22, 23, 24) were determined in 12-13-year-old children who were life-long residents in a naturally high (3.70 ppm) and in a near optimal (0.62 ppm) fluoride area. Enamel biopsies were taken by means of an acid-etch procedure, and the fluoride levels were measured with an adapted fluoride-ion-selective electrode. The enamel fluoride concentrations were related to the fluoride levels of the drinking water, and it appeared that the enamel fluoride concentrations of the different tooth types (except for the pre-molars) were associated with the length of the pre-eruptive period. In general, for both areas, the mean enamel fluoride concentrations increased from the central incisor to the lateral incisor and were found to be the highest in the canine, while the mean fluoride content of the first pre-molar nearly equaled that of the central incisor. No statistically significant differences (p greater than 0.05) were found between the enamel fluoride concentrations of the different tooth types or the etching depths, from different sexes.     

Effects of anterior tooth crown inclination on occlusal relationship—A study in three-dimensional reconstruction

ObjectiveThis study aims to analyze the relationship between the central incisor crown inclination and occlusal relationship via three-dimensional study.MethodsTen Chinese volunteers with normal occlusion were selected from physical examination of college students. Lateral cephalograms and CT scans were taken, and the CT data were imported into Simplant pro 11.04 to reconstruct three-dimensional model. In the three-dimensional model, every tooth was separated independently. The upper and lower central incisors were moved labial inclination(up) or lingual inclination(down) and then the upper and lower tooth were aligned based on the central incisor’s position according to the principles of Andrew’s six keys. Four groups were set up with different changes of central incisors. The upper and the lower arch were aligned again based on the moved central incisors. After every motion, the mesio-distal distances of upper and lower canines and first molars were recorded. All data were analyzed using t-test via SPSS19.0, and the significance level was set at 5%.ResultsThe results showed that the mesio-distal distances of occlusal relationship were different from normal occlusal relations, when either upper incisor crown inclination or lower incisor crown inclination was changed, and both upper and lower incisor crown inclination were moved in same or opposite direction. According to the statistical analysis, there was no significant difference when the changes of U1-L1 were no more than 10° (P > 0.05). But there was statistically significant difference (P < 0.05) when changes of U1-L1 were more than 20°.ConclusionsThe incisor crown inclination has influence on the establishment of occlusal relationships. The bigger difference upper and lower incisor crown inclination has, the more deviations from the normal occlusal relationship exist.     

五家渠市初中生牙齿审美对社会心理影响的调查

目的：调查研究错牙合畸形对五家渠市初中生社会心理的影响。方法：对五家渠市390名汉族初中生,男193人,女197人,平均年龄14．08±0．84岁。进行牙科审美社会心理影响量表（PIDAQ中文版）问卷调查。按照错牙合畸形切牙分类法标准和个别正常牙合标准进行检查登记,分成5组：切牙I类组、切牙II1分类组、切牙II2分类组、切牙III类组和个别正常牙合组。采用Kruskal－Wallis H秩和检验进行数据分析。结果：在社会影响方面,除了切牙III类与个别正常牙合组得分有统计学差异外（P＜0．0125）,与其余3组比较均无统计学差异（P＞0．0125）,切牙III类组比个别正常牙合组得分高4分。在审美态度方面,除了切牙III类与切牙II1分类组得分无统计学差异外（P＞0．0125）,与其余3组比较均有统计学差异（P＜0．0125）,切牙III类组比切牙I类组高3分,比切牙II2分类组高2．5分,比个别正常牙合组高4分。在牙齿自信方面,除了切牙III类与个别正常牙合组得分有统计学差异外（P＜0．0125）,与其余3组比较均无统计学差异（P＞0．0125）,切牙III类组比个别正常牙合组得分低4分。结论：错牙合畸形对初中生社会心理存在一定的不良影响,特别是错牙合畸形加重了初中生的社会影响,降低了其牙齿自信,切牙II1分类和切牙III类加重了初中生的审美态度影响。鼓励患有错牙合畸形的初中生尽早进行正畸治疗,对可能出现的心理问题及时进行疏导和干预。     

Lower incisor tooth development studied in protein-deficient rats with intravital labelling techniques

Seventy male rats were divided equally into control and experimental groups at weaning, and fed on diets containing 21.7 and 7.6 per cent protein respectively. Animals received injections of oxytetracycline hydrochloride and D.C.A.F. (2,4,bis)N,N′dicarboxyl methyl (amino methyl fluorescein) 2 and 1 weeks respectively before being killed. Five control and five experimental animals were killed after 1, 2, 3, 4, 6, 9 and 12 months. The left halfmandible was embedded in acrylic and 100-μm serial transverse sections of the lower incisor tooth studied by fluorescent microscopy and photographed. Measurements between the labels taken from a constant reference point on standardized photographic enlargements recorded dentine growth during the week between injections. No statistically-significant difference between control and experimental incisor tooth growth was apparent ( 0.1 < p < 0.2). Correlation between dentine production and weight of animals was very low and the incisor tooth growth was not significantly affected by protein deficiency.     

Quantification of the esthetics of dentists’ before and after photographs

PurposeThe purpose of this study was to measure dentists’ before and after restorative treatment photographs to identify four metrics to describe the esthetic improvement: (a) central incisor width-to-height ratio; (b) central-to-lateral incisor width ratio; (c) lateral incisor-to-canine width ratio; and (d) lateral incisor percentage offset.Materials and methodsInternet searches for “before after” and “veneers” and “prosthodontic” were used to obtain 198 before and after photographs of patient treatments showing the restoration of the six maxillary anterior teeth with porcelain veneers, crowns or a combination. The four metrics were measured using Adobe Photoshop. Groups were compared with repeated measures ANOVA followed by a post hoc Tukey–Kramer test with the variables of “Before or After Treatment”; “Treatment Type” (veneers, crowns or a combination) and “General Dentist or Prosthodontist”.ResultsMean central incisor width-to-height ratio was 91.7% before treatment, 80.8% after; mean central-to-lateral incisor width ratios were 69.9% and 64.7%; mean lateral incisor-to-canine width ratios were 85.3% and 81.4% and lateral incisor percentage offsets were 9.6% and 8.7%. There were significant (p < 0.05) differences for before and after treatment for all variables except central-to-lateral incisor width ratio. Differences between specialist and general dentist were not statistically significant.ConclusionsOn average, esthetic prosthetic treatment resulted in reduced central incisor width-to-height ratio, increased proportional width of the mesially positioned tooth of adjacent anterior teeth and reduced lateral incisor offset. The mean values of treatments by GPs and prosthodontists were not statistically significantly different.Clinical implicationsKnowledge of dentists’ optimal restorative treatments provides insight on the esthetic outcome of extensive prosthodontic therapy.     

Postoperative pain after the removal of root canal filling material using different techniques in teeth with failed root canal therapy: a randomized clinical trial

Objectives: This study evaluated the intensity and duration of postoperative pain after the removal of root canal filling material in retreatment procedures of upper incisor teeth with chronic apical periodontitis, using different techniques.

Materials and methods: One hundred and thirty-five patients requiring retreatment of upper incisor teeth with chronic apical periodontitis were included in the study. The patients were assigned to three groups of 45 patients, according to the method used to remove old canal filling material. In group 1, canal filling material was removed using hand files. In group 2, the canal filling material was removed with ProTaper universal retreatment (PTUR) instruments. In group 3, Reciproc instruments were used to remove canal filling material. Teeth were then medicated with calcium hydroxide and sealed using temporary filling material. The presence of postoperative pain was assessed after 6, 12, 24, 48 and 72?h, 7 days, and finally after 10 days.

Results: In all time intervals, except for 72?h, 7 days and 10 days, group 1 participants reported more intense postoperative pain than those in groups 2 and 3 (p?=?0.02). In all time intervals, there was no difference in the pain scores between groups 2 and 3 (p?=?0.08). In all groups, the intensity of postoperative pain decreased over time. The required time to remove canal filling material was less for the Reciproc group compared to the hand and ProTaper retreatment groups (p?=?0.032).

Conclusions: Hand files caused greater postoperative pain after non-surgical endodontic retreatment (NSER) of upper incisor teeth with chronic apical periodontitis compared to the ProTaper retreatment and Reciproc files.     

Social judgements made by children in relation to visible incisor trauma

Abstract – Aim: There is evidence to suggest that negative social judgements are made on the basis of poor dental aesthetics. This study sought to determine how children view other children with visible incisor trauma. Material and methods: Year 7 (aged 11–12 years) and year 10 (aged 14–15 years) school children (the participants) were invited to look at colour photographs of four different children’s faces and to make a social judgement about these children (the subjects). Participants were randomly allocated either: (i) pictures of children with visible incisor trauma or, (ii) pictures of the same children whose photographs had been digitally modified to restore incisor aesthetics. Using a previously validated child‐centred questionnaire, participants rated subjects using a four‐point Likert scale for three negative and six positive attributes. Total attribute scores were tested for significant differences, according to whether the subject had visible incisor trauma or not, using multivariate analysis of variance (P < 0.05, manova ). Results: 291 children completed the questionnaires, giving a response rate of 73%. Year 7 children viewed children with visible incisor trauma more negatively than the same child with normal incisor appearance. However, the converse was true for year 10 participants. Conclusion: Findings from this study concur with those from adult populations in that negative social judgements may be made on the basis of poor dental appearance. Interestingly, this would not appear to be the case in adolescence, which may relate to high levels of self‐monitoring in this age‐group. In view of the importance of appearance in adolescent social interaction, aesthetic dental treatment for children with incisor injury may yield important psychosocial benefits.