Objectives: The purpose of this in-vitro study was to evaluate the effects of three different surface preparation methods on the shear bond strength of orthodontic brackets bonded to zirconia and determine the most appropriate method. Methods: 45 zirconia and 30 leucite-reinforced porcelain mandibular premolar crowns were divided into 5 groups and received the following surface preparations: 37% phosphoric acid and non-hydrolyzed silane, 4% hydrofluoric acid and hydrolyzed silane, microetch with 50μ Al 2 O3 particles. A universal adhesive primer containing MDP was applied and the brackets were bonded with a bis-GMA composite resin. Shear bond strength (SBS) at bond failure and ARI score were recorded. Results: There was a statistically significant difference among the studied groups for the SBS. The highest mean SBS (11.03 MPA) was recorded for the zirconia/microetch group, and the lowest SBS (3.49 MPa) for the zirconia/phosphoric acid group. The leucite-reinforced porcelain/ hydrofluoric acid group had significantly more fractures than any other debond pattern. The zirconia/hydrofluoric acid group was the only one with a SBS (8.08 MPa) that fell within the recommended range of 6-8 MPa. This group also had a favorable debond pattern with most composite remaining on the bracket. Conclusions: Important consideration should be given to the surface preparation of porcelain and zirconia prior to bonding orthodontic attachments. Phosphoric acid etch is not an adequate surface preparation when bonding to zirconia. Hydrofluoric acid is not suitable when bonding to leucite-reinforced porcelain, as it is associated with a higher rate of surface fracture. Microetch with 50μ Al 2 O3 particles in combination with an MDP containing universal adhesive primer provided optimal mean shear bond strength, along with favorable debond patterns when bonding to zirconia. Hydrofluoric acid etch in combination with a silane and a universal primer containing MDP provided acceptable shear bond strength to zirconia. This protocol was not significantly different from zirconia prepared with microetch and either method can be successfully employed.

A thesis submitted to the College of Dental Medicine of Nova Southeastern University of the degree of Master of Science in Dentistry. ABSTRACT The significance of this research was to identify the optimal techniques to remove ceramic orthodontic appliances in order to prevent tooth-enamel fracture, pain, and esthetic complications. Discomfort and pain are common occurrences during orthodontic appliance removal. In debonding (bracket removal) appointments, less force, measured as reduced shear bond strength (SBS) is preferable because greater force creates more discomfort and pain. In a previous study, 24.3% of patients reported pain when metallic brackets were removed using a ligature-cutting plier, compared to 12.8% of patients reporting pain when a lift-off instrument was employed. These previous findings demonstrate the need to investigate new debonding removal methods which have less SBS to help reduce the pain experienced by orthodontic patients. Some recent studies have reported that orthodontic bracket debonding causes inevitable damage to the enamel surface. The debonding of ceramic orthodontic brackets can increase the risk of enamel damage. The application of heat to help debond a bracket can increase the temperature of the pulp chamber; this could injure pulp cells and threaten the long term vitality of the affected tooth. The purpose of this in-vitro study was to evaluate the safety and effectiveness of using a diode laser for the debonding of ceramic brackets in relation to the amount of debonding force required, the risk of direct force impact on enamel, and the risk of causing an adverse temperature increase inside the pulp chamber. The central hypothesis I investigated was that using a diode laser would facilitate the debonding of ceramic brackets by decreasing the SBS, increase the adhesive remnant index (ARI), and avoid causing an adverse temperature increase in the pulp chamber. I investigated these parameters with the goal of establishing an effective and safe protocol for debonding ceramic brackets. At present no guidelines exist, I recognized that guidelines are needed for using a diode laser to debond brackets in relation to the power level and duration of lasing. This study tested two types of ceramic brackets; a monocrystalline bracket called Radiance and polycrystalline ceramic bracket called Clarity. These brackets were selected because they are widely available and in common use. The experimental brackets were monocrystalline and polycrystalline: the laser power settings and lasing times were; negative control (not lased), lased at 2.5 watts for 3 and 6 seconds, and lased at 5.0 watts for 3 and 6 seconds. The diode laser treatments had little effect on the debonding SBSs for the removal of the Radiance monocrystalline brackets. Alternatively, the debonding of the Clarity polycrystalline brackets with laser treatment using 2.5 watts for 6 seconds, 5.0 watts for either 3 seconds or 6 seconds reduced the SBS. The debonding of the Radiance monocrystalline brackets with laser treatment using 2.5 watts for 3 seconds, and 5.0 watts for 6 seconds increased the ARI. The debonding of the Clarity polycrystalline brackets with laser treatment using 2.5 watts for 6 seconds, 5.0 watts for 3 seconds and 6 seconds increased the ARI. The increase in pulp chamber temperature likely to cause thermal injury to the pulp cells was measured against Zack and Cohen¡¯s in vivo standards (2.2¢ªC and, 5.5¢ªC).30 When compared to the 2.2¢ªC standard; the debonding of Radiance monocrystalline brackets with laser treatment using 2.5 watts for 3 seconds were within the standard, and the debonding of Clarity polycrystalline brackets using 2.5 watts for 3 seconds was cooler. When compared to the 5.5¢ªC standard, the debonding of Clarity polycrystalline brackets using 2.5 watts for 6 seconds was cooler. The research results showed that using a diode laser for debonding at 2.5 watts for 6 seconds decreased the SBS for Clarity polycrystalline brackets (reduced the force needed for debonding), increased ARI for Clarity polycrystalline brackets (increased adhesive on enamel), and did not increase the pulp chamber temperature by an injurious amount. The difference in the debonding SBS, ARI and pulp chamber temperatures of the two bracket types probably arose because of the difference in the designs of the two bracket pads. My research results demonstrate the long-term need to design brackets with pads which can be removed easily with a diode laser, leave more adhesive on enamel, and that do not cause injurious temperature increases within the pulp chamber. My research results also demonstrate why guidelines for bracket debonding using diode lasers are needed, which limit the power setting and lasing times. The debonding of brackets using diode lasers could benefit orthodontic patients and become more common if it can reduce the risk of tooth fracture, lower the sensation of pain, reduce the amount of enamel damage, and maintain the vitality of teeth in future studies.

No description available.

Aim: The aim of this study was to investigate if there is a beneficial effect on the prevalence of white spot lesions (WSL) in the mandibular and maxillary teeth when the teeth in the maxilla are treated with fluoride varnish compared to a placebo group. The null hypothesis was that there is no difference between the test and placebo group in development of WSL. Material and Method: 182 patients from three clinics in Scania county (Sweden) undergoing treatment with fixed orthodontic appliances were selected to participate, in the end 149 patients were included in the study. The patients were divided into two groups, one receiving a varnish of 7700 ppm fluoride (Fluor Protector S, Ivoclar Vivadent AG, Schaan, Liechtenstein) and one a placebo varnish. Pre- and post-treatment photos were taken and WSL was graded according to Gorelick index by two independent observers.  Results: No significant difference could be seen between the test and placebo group, neither on surface nor individual level. The results were based on both t-test and percentual calculations.  Conclusion: The null hypothesis could be accepted since no significant difference could be seen between the test or placebo group. Due to the loss of a number of patients, mainly because of loss in the original study and new exclusion criteria set by the authors, the results may have been conflicted. More research is therefore needed to draw any conclusions. / Syfte: Syftet med studien var att undersöka om det finns en effekt på förekomsten av white spot lesions (WSL) hos under- och överkäkens tänder när tänderna i överkäken behandlas med fluoridvarnish. Nollhypotesen sattes till att det inte finns någon skillnad mellan test- och placebogruppen i prevalens av WSL. Material och metod: Patienter från tre olika kliniker i Skåne deltog i studien, 149 av 182 deltagare fullföljde studien. Patienterna delades in i två grupper, en som fick ett fluoridvarnish med 7700 ppm fluorid (Fluor Protector S, Ivoclar Vivadent AG, Schaan, Liechtenstein) och en med placebovarnish. Kliniska foton togs innan samt efter behandling med fast apparatur som graderades och bedömdes enligt Gorelick-skalan för WSL av två oberoende observatörer. Resultat: Det fanns ingen signifikant skillnad mellan testgruppen och placebogruppen varken på individ- eller ytnivå. Resultatet baserades på både t-test och procentberäkningar. Slutsats: Nollhypotesen accepterades då ingen signifikant skillnad fanns mellan test- och placebogrupp. På grund av bortfall av patienter, både i originalstudien men även med anledning av exklusionskriterier satta för denna studie, kan resultatet ha påverkats. Mer forskning behövs därför för att dra några slutsatser.

Syfte: Studiens syfte är att med hjälp av enkäter utvärdera ungdomars upplevelser under besök hos ortodontist eller ortodontiassistent i samband med behandling med fast apparatur. Målsättningen är också att belysa om det eventuellt finns några skillnader i upplevelsen beroende på vilken behandlingsteknik som används vid tandreglering.  Material och metod: Studien är en del av ett större forskningsprojekt som har syftet att jämföra självligerande brackets (Damon) med konventionella brackets (Victory). Deltagarna i denna studie har efter varje behandlingstillfälle tilldelats en enkät. Frågorna handlar om hur vårdtagaren upplevt vårdgivarens kunskap, bemötande, acceptans och delgivning av information.  Resultat: Totalt ingår 113 vårdtagare i studien (54 pojkar och 59 flickor). Medelåldern vid behandlingsstart var 14,7 år. Båda teknikerna fick höga betyg, vilket innebär att vårdtagarna generellt är nöjda med behandlingarna. Fem av frågorna visade signifikanta skillnader vid jämförelse mellan Damon och Victory. Frågorna som handlade om information, förståelse, acceptans samt om vårdgivaren var hårdhänt, visade skillnad vid besök 4. För frågan gällande noggrannhet visades skillnad vid besök 3, 4 och 5. Ingen signifikant skillnad mellan könen visades för någon fråga.  Slutsats: Utfallet indikerar att svensk ortodontisk vård fungerar bra ur vårdtagarnas perspektiv, vilket är något som bör upprätthållas inom tandvården. Få skillnader noterades vid jämförelse mellan behandling med Damon och Victory. Resultatet kan indikera att vårdtagarens upplevelse av bemötande är mer positivt vid behandling med Damon, samt att den ortodontiska behandlingen upplevs mindre hårdhänt jämfört med Victory. / Aim: The aim of this study is to examine the experiences of adolescents, during visits at the orthodontist or orthodontic assistant, for fixed appliances treatment. The purpose is also to examine possible differences in experience when treated with self-ligating or conventional brackets.  Material and method: This study is a part of a larger project that aims to compare self-ligating brackets (Damon) with conventional brackets (Victory). After each treatment session the patients received a questionnaire. The questions concerning the patients experience of the care givers way of showing knowledge, acceptance, responsibility of interaction and the way of communication the information.  Result: In total 113 participants were included in the study (54 boys and 59 girls). At the beginning of the treatments the average age of the participants were 14,7 years. Both techniques received high grades, meaning the patients generally were satisfied with the treatments. Five questions showed significant differences in comparison between the techniques. The questions about information, understanding, acceptance and whether the caregiver was harsh in handling, showed differences at visit 4. Regarding the question about accuracy, a difference was noted during visit 3, 4 and 5. No significant difference between the sexes was shown for any question.  Conclusion: From the patient ́s point of view Swedish orthodontic care is satisfying. Few differences were noted when comparing the appliances. The results may indicate that treatment with Damon gives a more positive and less harshly experience in comparison with Victory. / CROWDIT

Indiana University-Purdue University Indianapolis (IUPUI) / Craniofacial growth results from both environmental and genetic factors over time. It would be exciting to isolate genetic factors that influence treatment responses from patients undergoing orthodontic treatment. Genetic genotyping and analysis of orthodontic patients is a new technologic advancement. The aim of this retrospective study is to examine the relationship of a specific single nucleotide polymorphism (SNP), rs6180, of the Growth Hormone Receptor (GHR) gene with various craniofacial length parameters in patients who have received Herbst appliance therapy as part of orthodontic treatment. An initial lateral cephalometric radiograph was taken along with two buccal cheek swabs. The cells obtained have undergone DNA isolation with the Puregene method in microcentrifuge tubes (Gentra Systems, Minneapolis, MN). Upon termination of functional appliance therapy (post-Herbst), a final lateral cephalometric radiograph was taken. To analyze the genetic polymorphism and determine genotype, polymerase chain reaction (PCR) and allelic discrimination were done using the 7000 Sequence Detection System (Applied Biosystems). Lateral cephalometric radiographs (initial, post-Herbst) of 25 patients were digitized and measured using the Dolphin Imaging program. Cephalometric measurements (S-N, S-A, Co-Go, Go-Gn, Ar-Gn, Go-Gn) were used to identify mandibular and craniofacial morphologic changes. Changes in Z-scores based on standards from the Michigan Growth Study were then converted to slow or normal growth status by slow being when the Z-score difference between the initial and final measurements is less than zero. The number of subjects with a slow versus normal growth status was compared to GHR polymorphism genotype. Statistical analysis of Hardy-Weinberg equilibrium and the changes in craniofacial length Z-scores in relation to a patient's genotype were performed using chi-square analysis. Results: The genotype frequencies were in Hardy-Weinberg equilibrium. Z-score differences for the S-A measurement was the only one found to be significant (p=0.005).

Indiana University-Purdue University Indianapolis (IUPUI) / The current movement in dentistry is to provide treatment that is evidence-based rather than opinion-based. Unfortunately, there is a lack of evidence for most orthodontic appliances. Much work has been done to find the appropriate load system to move teeth, but research has only been done with laboratory techniques that may not be applied clinically. Ideally, appliances should be tested in all three dimensions with techniques (e.g. type of ligation) that replicate clinical procedures. This can be accomplished with a new patented technology, the orthodontic force tester (OFT). The OFT allows an entire arch with brackets and a full arch wire to be set up while measurements are made on target teeth. With the OFT, appliances can be tested to ascertain if they provide the prescribed load system, and if not, then modify them or develop new ones. In this experiment two different commercially available prefabricated closing loop arch wires (keyhole and teardrop) were tested with variations in gable bends, interbracket loop position, and activation. The application being tested is closing space between a lateral incisor and canine in a first premolar extraction case after the canine has been retracted. While the trend shows that the keyhole loop produces higher overall force the two loops are not significantly different in the forces or moments that they generate. The one exception is that the keyhole loop produces higher lingual forces at the canine when the loop is in the mesial position. Also, few wire configuration were able to produce M/F sufficient to translate teeth. The wire configurations that can provide the proper load system to translate teeth in the lingual direction at the incisor were in the mesial position and had second order gable bends at the alpha position. The loop design had little effect on the M/F ratios.

No description available.

Hörntänderna i maxillan är efter visdomständerna de tänder som oftast blir retinerade. Prevalensen varierar mellan 1-3%. En retinerad överkäkshörntand har ofta en ektopisk placering. Detta kan leda till att eruptionsriktningen blir felaktig och därmed kan tanden orsaka skador på de angränsande incisivernas rötter. För att minska risken för detta krävs tidig diagnostik, i 9-11 års ålder.Den vanligaste åtgärden för palatinalt displacerade hörntänder är extraktion av mjölkhörntänderna för att underlätta spontaneruption av de efterföljande permanenta hörntänderna. Om enbart denna behandling inte är tillräcklig eller om den permanenta hörntanden ligger för djupt måste kirurgisk friläggning ske. Detta sker i kombination med efterföljande ortodontisk behandling.I Sverige används idag två typer av kirurgisk friläggning; öppen och sluten. Vilken typ av friläggning som används tycks vara lokalt betingat. I Malmöregionen används oftast öppen friläggning medan i Jönköpingsregionen sluten friläggning är vanligast.I denna studie jämförs behandlingsutfallet hos patienter där öppna och slutna friläggningar gjorts. Framförallt utvärderas om det finns någon signifikant skillnad i behandlingstid, från friläggning till dess att den ortodontiska behandlingen är färdig. Hänsyn tas till typ av friläggning och om tanden ligger palatinalt eller buckalt retinerad. Det undersöks även vid vilken ålder friläggning gjorts samt vilken typ av retentionapparatur som använts.I gruppen med öppen friläggning var patienterna i genomsnitt 15,2 år respektive 12,9 år i gruppen med sluten friläggning. Den totala behandlingstiden från friläggning till avlägsnande av apparatur visade sig vara signifikant kortare i gruppen som fick öppen friläggning jämfört med gruppen som fick sluten friläggning. / The maxillary canines are after the third molars, the most frequently impacted teeth. The incidence varies between 1-3%. Impacted maxillary canines are often related to ectopic position, which can lead to an incorrect direction of eruption and thus cause damage to the adjacent incisors roots.The most common treatment for palatally displaced canines is extraction of the primary canines to facilitate spontaneous eruption of the succeeding permanent teeth. If this treatment is not sufficient or if the permanent canine lies too deep, surgical exposure is needed. This occurs in combination with orthodontic treatment.In Sweden two types of surgical exposures are practiced; open and closed. Which type of exposure is used seems to be locally induced. In Malmö the open exposure is most frequently practiced while in Jönköping the closed exposure is the treatment of choice.The aim of this study is to compare the treatment outcome in two groups of patients, treated either with an open or a closed exposure. It was evaluated whether any significant difference was found in the overall treatment time, from exposure until completed orthodontic treatment. Consideration was given to type of exposure and weather the tooth was palatally or buccally impacted. The age of the patients when the exposures occurred and the type of retention used in the different groups were also examined.The mean age for the patients treated with an open exposure was 15.2 years compared to 12.9 years in the other group. The total time of treatment from exposure to removal of the appliances was significantly shorter in the group with open exposure.

SammanfattningSyfte: Studiens mål var att uppnå kunskap angående olika interceptiva ortodontiska behandlingar, undersöka vilka ortodontiska behandlingar som är vanligast förekommande hos allmäntandläkare och rekommenderade av svenska ortodontister samt att undersöka om de vanligaste behandlingarna är de som lärs ut vid odontologiska fakulteten i Malmö. Potentiella skillnader mellan grupperna undersöktes också. Material och metod: En PubMed-sökning gjordes för att undersöka litteratur för de apparaturer som används mest frekvent. Ett frågeformulär utformades och skickades till 169 ortodontister med konsultationsverksamhet för att undersöka användningen av olika apparaturer som sker i samarbete med allmäntandläkare. Resultat: Totalt inkluderades 153 artiklar i litteraturstudien och frekventa behandlingar presenterades. Den mest använda apparaturen för behandling av:- Korsbett var Quad Helix- Frontal invertering var klammerplåt med Z-fjäder - Klass II malocklussion var van Beek aktivator.En signifikant skillnad mellan grupperna hittades; kvinnliga ortodontister rekommenderade allmäntandläkare aktivator med extra oralt drag vid behandling av Klass II malocklussion i större utsträckning än manliga ortodontister. Slutsats: Valet av apparatur överensstämde till största delen med vad som anses vara det mest effektiva enligt de artiklar som inkluderats i studien. Det var även dessa apparaturer som används i studentundervisningen vid odontologiska fakulteten i Malmö.Skillnaderna i valet av apparatur mellan de manliga och de kvinnliga ortodontisterna beror troligtvis på den ojämna könsfördelningen av nyutexaminerade ortodontister de senaste 50 åren. / AbstractObjective: The aim of the present study was to obtain knowledge about different interceptive orthodontic treatments, investigate which orthodontic treatments are most frequently used by general practitioners and recommended by Swedish orthodontists and to see if the most common treatments corresponded to the educational dental program in orthodontics at Malmö University. Potential differences among groups were also investigated. Materials and methods: A PubMed search was made to investigate the literature of the most frequently used appliances in orthodontic treatment concerning the diagnoses and the appliances used in general practices. A questionnaire was sent to 169 consulting orthodontists to investigate the use of different appliances in cooperation with general practitioners.Results: A total of 153 articles were included in the literature study and frequently used treatments were presented.The most common appliance for correction of: - Posterior crossbite was the Quad Helix.- Anterior crossbite was a plate with Z-springs.- Class II malocclusion was the headgear activator, according to van Beek.A significant difference between genders was found, i.e. that female orthodontists recommended headgear activator more often than males for Class II in general practise. Conclusions: The choice of appliances mostly corresponded to what is most effective according to the literature included in the study and these are used in the educational program for dental students in Malmö.The differences between the genders of the orthodontists in choice of treatment are most likely due to the gender distribution of becoming orthodontists during the last five decades.