Autotransplantation of a Maxillary Premolar to Replace a Central Incisor: A Seven-Year Follow-Up.

Purpose: To discuss the transplantation of a maxillary premolar to replace a maxillary central incisor in a seven-year follow-up period.
Methods: An avulsed permanent maxillary central incisor was reimplanted by a pediatric dentist but it presented progressive external root resorption. Transplantation of the maxillary right first premolar was planned, as the patient presented a Class II malocclusion with increased overjet that would be treated with extractions of the maxillary premolars.
Results: The transplanted tooth did not present any negative symptoms other than discoloration, which was treated with bleaching for three years. At the end of a three- year follow-up period, a full ceramic restoration was done to improve translucency properties to provide better esthetics. The transplanted tooth presented healthy periapical and periodontal tissues in both clinical and radiographic examinations at the end of the seven-year follow-up period.
Conclusions: Autotransplantation of maxillary premolars can be a viable alternative to provide adequate physiologic and esthetic components for avulsed and reimplanted permanent incisors that presented unsuccessful results.

C-telopeptide pyridinoline crosslinks of type I collagen, soluble RANKL, and osteoprotegerin levels in crevicular fluid of dental implants with peri-implantitis: a case-control study.

PURPOSE: To evaluate levels of C-telopeptide pyridinoline crosslinks of type I collagen (ICTP), soluble receptor activator of nuclear factor-kappa B ligand (sRANKL), and osteoprotegerin (OPG) in the crevicular fluid of endosseous dental implants with the clinical diagnosis of peri-implantitis and to compare these with the crevicular fluid of clinically healthy implants. METHODS: Peri-implant crevicular fluid samples were obtained from 18 root-type implants with peri-implantitis in 12 patients and 21 clinically healthy implants in 16 other patients. Modified Plaque Index, probing depths, Gingival Index, and bleeding on probing were recorded at the crevicular fluid sampling sites. ICTP, sRANKL, OPG, and albumin levels in the peri-implant crevicular fluid samples were investigated by enzyme-linked immunosorbent assay. The clinical and biochemical data were evaluated statistically using Mann-Whitney U test. Spearman correlations were used to determine relationships between the biochemical data and the clinical parameters. RESULTS: Duration of implant loading, peri-implant crevicular fluid volume, and all clinical periodontal measurements were significantly greater in the peri-implantitis group than in the clinically healthy group. Total amounts of ICTP were significantly higher in the peri-implantitis group than in the healthy group. sRANKL concentrations, OPG total amounts, and OPG concentrations were significantly higher in the healthy group. CONCLUSION: The present findings suggest that local levels of ICTP and OPG reflect an increased risk of alveolar bone loss around dental implants, and their local levels may help to distinguish diseased and healthy sites.

Copper-catalyzed trifluoromethylation of aryl iodides with potassium (trifluoromethyl)trimethoxyborate.

Potassium (trifluoromethyl)trimethoxyborate is introduced as a new source of CF(3) nucleophiles in copper-catalyzed trifluoromethylation reactions. The crystalline salt is stable on storage, easy to handle, and can be obtained in near-quantitative yields simply by mixing B(OMe)(3), CF(3)SiMe(3), and KF. The trifluoromethylation reagent allows the conversion of various aryl iodides into the corresponding benzotrifluorides in high yields under mild, base-free conditions in the presence of catalytic quantities of a Cu(I)/1,10-phenanthroline complex.

Stereoselective total synthesis of etnangien and etnangien methyl ester.

A highly stereoselective joint total synthesis of the potent polyketide macrolide antibiotics etnangien and etnangien methyl ester was accomplished by a convergent strategy and proceeds in 23 steps (longest linear sequence). Notable synthetic features include a sequence of highly stereoselective substrate-controlled aldol reactions to set the characteristic assembly of methyl- and hydroxyl-bearing stereogenic centers of the propionate portions, an efficient diastereoselective Heck macrocyclization of a deliberately conformationally biased precursor, and a late-stage introduction of the labile side chain by means of a high-yielding Stille coupling of protective-group-free precursors. Along the way, an improved, reliable protocol for a Z-selective Stork-Zhao-Wittig olefination of aldehydes was developed, and an effective protocol for a 1,3-syn reduction of sterically particularly hindered beta-hydroxy ketones was devised. Within the synthetic campaign, a more detailed understanding of the intrinsic isomerization pathways of these labile natural products was elaborated. The expedient and flexible strategy of the etnangiens should be amenable to designed analogues of these RNA-polymerase inhibitors, thus enabling further exploration of the promising biological potential of these macrolide antibiotics.

Total synthesis of etnangien.

The first total synthesis of the potent RNA-polymerase inhibitor etnangien is described, which establishes unequivocally the relative and absolute configuration of this sensitive macrolide antibiotic. Key features of the expedient and modular synthesis include stereoselective substrate-controlled boron- and tin-mediated aldol couplings to set the characteristic sequences of methyl and hydroxyl bearing stereogenic centers with high degrees of stereoselectivity and yield, an efficient Heck macrocyclization of a conformationally restricted substrate, and a late-stage introduction of the labile side chain. The convergent approach should be amenable to designed analogues.

Stereochemical determination and complex biosynthetic assembly of etnangien, a highly potent RNA polymerase inhibitor from the myxobacterium Sorangium cellulosum.

A potent novel analogue of the natural macrolide antibiotic etnangien, a structurally unique RNA polymerase inhibitor from myxobacteria, is reported. It may be readily obtained from fermentation broths of Sorangium cellulosum and shows high antibiotic activity, comparable to that of etnangien. However, it is much more readily available than the notoriously labile authentic natural product itself. Importantly, it is stable under neutral conditions, allowing for elaborate NMR measurements for assignment of the 12 hydroxyl- and methyl-bearing stereogenic centers. The full absolute and relative stereochemistries of these complex polyketides were determined by a combination of extensive high-field NMR studies, including J-based configuration analysis, molecular modeling, and synthetic derivatization in combination with an innovative method based on biosynthetic studies of this polyketide which is also presented here. A first look into the solution conformation and 3D structure of these promising macrolide antibiotics is reported. Finally, the complete biosynthetic gene cluster was analyzed in detail, revealing a highly unusual and complex trans-AT type polyketide biosynthesis, which does not follow colinearity rules, most likely performs programmed iteration as well as module skipping, and exhibits HMG-CoA box-directed methylation.

Diastereodivergent aldol reactions of beta-alkoxy ethyl ketones: modular access to (1,4)-syn and -anti polypropionates.

Asymmetric substrate-controlled aldol reactions of ethyl ketones of type 4 with aldehyde 3 are reported. Modular access to all possible syn- and anti-aldol products was obtained by careful choice of reaction conditions. To achieve good selectivities in this diastereodivergent approach, selection of the protective group on the beta-oxygen of the enolate (R (2)) was of critical importance.

5-year longitudinal study of survival rate and periodontal parameter changes at sites of maxillary canine autotransplantation.

BACKGROUND: Although dental transplantation is an accepted treatment modality, few studies have evaluated the prognosis for autotransplantation of maxillary canines, and changes in clinical periodontal parameters still need to be demonstrated. The objectives of this long-term study were to evaluate the prognosis and changes in clinical attachment level (CAL), probing depth (PD), soft tissue recession (REC), and radiographic bone level changes between years 1 and 5 for autotransplanted maxillary canines. METHODS: Thirty subjects with 32 impacted canines were scheduled for transplantation. Transplanted teeth were splinted for 4 weeks, and endodontic treatments were performed within 1 year after the operation. Radiographs were taken, and PD and CAL were measured for up to 5 years. Progressive root resorption was observed in two teeth, and one tooth was extracted during year 4. RESULTS: The survival rate was 93.5%. CAL and PD tended to increase slightly at all sites, especially at palatal sites after transplantation, whereas the greatest CAL and PD were found at approximal sites, and REC was the same as natural teeth. CONCLUSIONS: Maxillary canine transplantation can be a reliable treatment alternative. Clinical measurements demonstrated long-term stability. Based on the literature and the present findings, maxillary canine transplantation can be suggested as a promising treatment modality.

Osteoprotegerin levels in peri-implant crevicular fluid.

AIMS: To evaluate the levels of soluble receptor activator of nuclear factor-kappaB ligand (sRANKL) and osteoprotegerin (OPG) in crevicular fluid of endosseous dental implants. METHODS: Eighty-six implants in 39 patients were evaluated. All patients were treated with root-type implants placed at least 16 months and loaded at least 12 months before the examination. Peri-implant crevicular fluid (PICF) samples were obtained from buccal and lingual aspects of implants. Modified plaque index, probing depth, gingival index, and bleeding on probing (BOP) were recorded at four sites per implant. PICF levels of sRANKL and OPG were analysed by ELISA. Spearman's correlations were utilised to relate biochemical data and clinical parameters. RESULTS: The PICF level of sRANKL did not show significant correlation with the clinical parameters or the OPG level. The total amount of OPG was positively correlated with PICF volume, gingival index, and BOP (P<0.05) and negatively correlated with pack years (P<0.05). CONCLUSION: The findings of this preliminary study suggest that the crevicular fluid level of OPG deserves further investigation as a possible marker to evaluate the health status of surrounding tissues of dental implants, as this was not the case for the sRANKL level. Larger scale studies, particularly in peri-implantitis cases, may shed more light on this subject.

Effect of platelet-rich plasma on gingival and periodontal ligament fibroblasts: new in-vitro growth assay

The use of platelet-rich plasma (PRP) as a source of growth factors is reported to be beneficial for periodontal regeneration. The aim of this study was to evaluate its effect on gingival and periodontal ligament fibroblast healing on a special growth assay designed by the working group. A wound with a 5 mm of diameter has been performed on periodontal ligament (PDL) and gingival fibroblast (GF) cell cultures. The cell wells were divided into five groups. The control group received only DulbeccoÆs modified EagleÆs medium/ HamÆs (DMEM) and the test groups received 0.5% PRP with 1/3 or 1/2 thrombin; 0.1% PRP with 1/3 or 1/2 thrombin. All of the groups were stained with haemotoxylene-eosine on days 2, 5, 7, 9 and 11. Digital screenings were performed on each time stop and the results were interpreted by means of % surface area covered by the cells. The results showed that 0.1% PRP with 1/3 thrombin group have closed up the wound circle in GF group at day 9 and in PDL group at days 9 and 11 with a significant difference when compared with other groups. GF response was significantly better than PDL cell response starting from day 5. Concluding, PRP favored wound closure in PDL and GF cell cultures and the developed growth assay may be utilized in future investigations of the biological basis of periodontal wound healing.

Efficient one-pot synthesis of biologically active polysubstituted aromatic amines.

An efficient and modular one-pot synthesis of polysubstituted aromatic amines by a mild reductive amination procedure is described and the biological potential of these nitrogen-centered compounds is demonstrated by growth inhibition of murine connective tissue cells and microscopy-based morphological studies.

The effectiveness of a single osteointegrated implant combined with pendulum springs for molar distalization.

The aim of this report was to present the clinical efficiency of a single osteointegrated implant combined with pendulum springs for molar distalization. A 15-year-old girl sought treatment for irregular anterior teeth and poor smile esthetics. A novel appliance was designed that combined osteointegrated implants with 0.032-in beta-titanium wire and pendulum springs. The treatment results were evaluated from lateral cephalometric radiographs. Distalization of the maxillary first molars was achieved in 6 months. Total treatment time was 21 months. Facial esthetics improved as a consequence of treatment. This appliance design offers reliable molar distalization, even when absolute anchorage is required.

Osseointegrated implants with pendulum springs for maxillary molar distalization: a cephalometric study.

INTRODUCTION: Maxillary molar distalization is a common treatment approach for patients with Class II malocclusions who do not require extractions. Despite the many advantages of pendulum appliances, the maxillary incisors and premolars tend to shift mesially as the maxillary molars move distally. The purpose of this study was to investigate anchorage loss in patients treated with palatal osseointegrated implants combined with pendulum springs. METHODS: Pretreatment and posttreatment lateral cephalometric films of 30 consecutively treated patients were examined. One group (n = 15) had been treated with conventional pendulum appliances, and the other group (n = 15) was treated with palatal osseointegrated implants combined with pendulum springs. RESULTS: In the pendulum group, significant distal tipping of the maxillary first molars and mesial tipping of the maxillary premolars were noted. Distalization of the maxillary first molars, mesialization of the maxillary first premolars, and proclination of the maxillary left central incisor were significant in the linear measurements. In the implant group, the distal tipping of the maxillary first molars and first premolars and the increases in SNGoGn, FMA, Na Me, and Na ANS were significant. Intergroup comparisons showed that changes in the maxillary first premolars, maxillary central incisors, and vertical measurements were significant. CONCLUSIONS: The use of palatal osseointegrated implants is reliable and provides absolute anchorage.

Directed reductive amination of beta-hydroxy-ketones: convergent assembly of the ritonavir/lopinavir core.

An efficient procedure for the directed reductive amination of beta-hydroxy-ketones (3) for the stereoselective preparation of 1,3-syn-amino alcohols (6) is reported. The operationally simple protocol uses Ti(iOPr)4 for coordination of the intermediate imino alcohol (5) and PMHS as the reducing agent. The method was expanded to an asymmetric aldol reductive amination sequence to allow a highly convergent synthesis of the hydroxy-amine core of the HIV-protease inhibitors ritonavir and lopinavir. [reaction: see text].

Periodontal conditions associated with space maintainers following two different dental health education techniques.

The aim was to investigate the effect of fixed and removable space maintainers on periodontal status of children and to compare the efficiency of verbal and written dental health education. 52 healthy children aged between 7-10 years who will be treated with fixed or removable appliances were divided into two subgroups to whom were given verbal and written dental education. Plaque index, bleeding index and mean pocket depth scores of the teeth were recorded at baseline and 3, 6 and 9 months after application. Plaque, bleeding index and mean pocket depth scores showed significant difference in the appliance groups in the follow-ups. Plaque index scores displayed a positive correlation with the duration of both appliances. The difference between pocket depth scores were found to be significant in the follow-ups in both appliance groups while it was insignificant between education groups and significant increase in bleeding index scores was observed in both appliance groups and education techniques given. It is concluded that both removable and fixed space maintainers can result in inflammation on periodontal tissues of the children.

Cryosurgical treatment of gingival melanin pigmentation with tetrafluoroethane.

OBJECTIVE: To introduce 1,1,1,2 tetrafluoroethane (TFE), as a new material for cryosurgery of gingival melanin pigmentation (GMP). STUDY DESIGN: Twenty-one patients with GMP were treated using a TFE-cooled cotton swab. Standard digital images of pigmented areas were measured preoperatively and postoperatively with image-analyzing software. The Mann-Whitney U test was used for statistical analysis. RESULTS: Keratinization was completed 3 to 4 weeks after application, without any trace of pigmentation. Statistical analysis revealed a significant difference between preoperative and postoperative measurements of pigmented areas (P < .05). During the follow-up period, no side effects were observed and improved esthetics were maintained up to month 30. CONCLUSIONS: The clinical outcomes of cryosurgery with TFE for treatment of GMP are very satisfactory. The use of TFE for cryosurgical treatment of GMP is practical and inexpensive. Moreover, unlike other cryosurgery methods no special equipment is required, and it is safe to store in the dental clinic.

Comprehensive therapy of a fusion between a mandibular lateral incisor and supernumerary tooth: case report.

The term fusion is used to define a developmental anomaly characterised by the union of two adjacent teeth. In the case reported here, clinical and radiographic examinations suggested a unilateral fusion between the mandibular left permanent incisor and a super-numerary tooth. Radiographs showed that the fused teeth had two distinct pulp chambers and canals. A diagnosis of chronic periapical abscess of the supernumerary tooth was made. Before root canal therapy, a periodontal surgical procedure was performed to section the central incisor and its fused supernumerary. Also, odontoplasty was performed on the roots, to establish an anatomy consistent with a normal central incisor. Later, the chronic apical abscess on the supernumerary tooth was instrumented chemo-mechanically, root canal filling was performed and an anterior composite resin restoration was placed. The patient was evaluated for one year after root canal therapy. The tooth was asymptomatic, not exhibiting any pathological root resorption or alveolar resorption, and the anterior composite restoration was intact. Instead of extracting the supernumerary tooth, the application of endodontic, periodontal, and restorative procedures proved to be an alternative treatment.