| 1. |
- Bertl, Kristina, et al.
(författare)
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Does the time-point of orthodontic space closure initiation after tooth extraction affect the incidence of gingival cleft development? A randomized controlled clinical trial.
- 2020
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Ingår i: Journal of Periodontology. - : John Wiley & Sons. - 0022-3492 .- 1943-3670. ; 91:5, s. 572-581
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Tidskriftsartikel (refereegranskat)abstract
- Background: Gingival clefts (GC) develop frequently during orthodontic space closure and may compromise the treatment outcome. This study assessed whether the time-point of orthodontic space closure initiation, after permanent tooth extraction, affects the incidence of GC. Methods: In 25 patients requiring bilateral premolar extraction due to orthodontic reasons, one premolar, chosen at random, was extracted 8 weeks before space closure initiation (“delayed movement”, DM), while the contralateral premolar was extracted one week before (“early movement”, EM) (“treatment group”). Presence/absence of GC after 3 and 6 months (“time-point”) was recorded and any association with various parameters (i.e., treatment group, time-point, gender, jaw, craniofacial growth, gingival biotype, buccal bone dehiscence after extraction, space closure) was statistically assessed. Results: Twenty-one patients contributing with 26 jaws were finally included in the analysis. Overall, GC were frequent after 3 (DM: 53.9%; EM: 69.2%) and 6 months (DM: 76.9%; EM: 88.5%). EM (p=0.014) and larger space closure within the study period (p=0.001) resulted in a significantly higher incidence of GC. Further, there was a tendency for GC development in the presence of buccal bone dehiscence (p=0.052) and thin gingival biotype (p=0.054). “Fast movers” (herein cases with a tooth movement ≥ 1mm per month) developed a GC in > 90% of the cases already after 3 months. “Slow movers” developed a GC only in 25 and 70% after 3m and FE, respectively. Conclusions: GC development is a frequent finding during orthodontic space closure and seems to occur more frequently with early tooth movement initiation and in “fast movers”.
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| 2. |
- Bertl, Kristina, et al.
(författare)
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Reproducibility of intraoral photography for pink and white tissue assessment : Is it worth the hassle?
- 2019
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Ingår i: Journal of Prosthodontic Research. - : Elsevier. - 1883-1958 .- 2212-4632. ; 63:4, s. 404-410
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To assess the effect of the shooting angle variation on linear and planimetric measurements of the pink and white tissues on intraoral photographs. METHODS: From intraoral three-dimensional (3D) scans of the anterior region in 10 patients, ninety-nine two-dimensional (2D) "scan pictures" each were generated with different shooting angles, each varying in 5° horizontal and vertical increments. Eleven intraoral photographs of each patient and tooth site were taken free-hand: one shot at baseline and 5 shots after 3 and 6 months at slightly varying shooting angles. Papilla height (PH) and area (PA) and tooth crown area (TCA) were estimated on all photographs; the "best-match-to-baseline" photograph from those taken at 3 and 6 months was chosen by 6 evaluators. RESULTS: Within the first 10° of deviation from the baseline shooting angle, measurements on the 2D "scan pictures" distorted ≤0.5 mm for PH and ≤10% for PA and TCA. Compared to baseline, only 6 out of 100 photographs presented ≥0.5 mm difference in PH, none of the TCA measurements showed distortion ≥10%, and only in 4 instances a ≥10% distortion of the PA was observed. Poor to moderate inter- and intra-rater agreement in choosing the "best-match-to-baseline" photograph was found, but photographs with clinically relevant changes were only seldomly chosen. CONCLUSIONS: Deviations in the shooting angle ≤10° from the baseline shot cause clinically negligible distortions in linear and planimetric measurements. Highly comparable intraoral photographs of the anterior maxillary teeth can be captured "free-hand" in slightly varying perspective, and then selecting the "best-match-to-baseline".
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| 3. |
- Nemec, Michael, et al.
(författare)
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Maxillary lateral incisor agenesis is associated with maxillary form : a geometric morphometric analysis
- 2023
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Ingår i: Clinical Oral Investigations. - : Springer. - 1432-6981 .- 1436-3771. ; 27:3, s. 1063-1070
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Tidskriftsartikel (refereegranskat)abstract
- Background and objectiveAgenesis of the maxillary lateral incisor occurs in up to 4% of all individuals and requires mul- tidisciplinary treatment. Its developmental origins, however, are not fully understood. Earlier studies documented genetic factors contributing to agenesis but also an association with craniofacial morphology. In this study, we assessed the associa- tion between maxillary morphology and lateral incisor agenesis by a geometric morphometric approach to disentangle the roles of developmental plasticity and genetic factors.Materials and methodsWe quantified the maxillary alveolar ridge by 19 two-dimensional landmarks on cross-sectional images of 101 computed tomography scans. We compared the shape and size of the alveolar ridge across patients with uni- lateral or bilateral agenesis of maxillary lateral incisors and patients with extracted or in situ incisors.ResultsThe maxillary alveolar ridge was clearly narrower in patients with agenesis or an extracted incisor compared to the control group, whereas the contralateral side of the unilateral agenesis had an intermediate width. Despite massive individual variation, the ventral curvature of the alveolar ridge was, on average, more pronounced in the bilateral agenesis group com- pared to unilateral agenesis and tooth extraction.Conclusions This suggests that pleiotropic genetic and epigenetic factors influence both tooth development and cranial growth, but an inappropriately sized or shaped alveolar process may also inhibit normal formation or development of the tooth bud, thus leading to dental agenesis.Clinical relevanceOur results indicate that bilateral agenesis of the lateral incisor tends to be associated with a higher need of bone augmentation prior to implant placement than unilateral agenesis.
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| 4. |
- Bertl, Kristina, et al.
(författare)
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A Wide Mesio-Distal Gap Distance in Sites of Congenitally Missing Maxillary Lateral Incisors Is Related to a Thin Bucco-Palatal Alveolar Ridge Width
- 2016
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Ingår i: Clinical Oral Implants Research. - : John Wiley & Sons. - 0905-7161 .- 1600-0501. ; 27:S13 : Abstracts of the EAO Congress, s. 218-219
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Background: In cases of a missing maxillary lateral incisor, an implant-supported crown is often the treatment of choice in order to avoid affecting intact adjacent teeth; however, proper implant placement requires a specific minimum amount of alveolar ridge bone volume. In general, alveolar ridge development is depended on tooth development and eruption; consequently, tooth loss has major impact on alveolar ridge dimensions and tooth agenesis seems to impair proper alveolar ridge development. It seems thus reasonable to consider that the impact of tooth agenesis on alveolar ridge development might depend on the gap width, i.e. the distance between the neighboring – regularly erupted – teeth. In particular, the influence from the adjacent teeth on alveolar ridge development would be diminished with an increasing mesio-distal gap distance, which in turn might result in deficient alveolar ridge dimensions, i.e. reduced height and bucco-palatal width in the center of the edentulous alveolar ridge. Aim/Hypothesis: This study aimed (a) to evaluate whether there is a correlation between the mesio-distal gap size and alveolar ridge dimension in patients missing the maxillary lateral incisor either due to agenesis or loss; (b) to determine the edentulous alveolar ridge dimension in the region of the missing maxillary lateral incisor and simulate straightforward implant placement; and (c) to assess any effect of tooth agenesis on the alveolar ridge dimension at the adjacent teeth (i.e. central incisor, canine). Material and Methods: Per protocol, 3 groups (n = 40 per group) were planned, including patients (1) with agenesis of one permanent maxillary lateral incisor (TA); (2) with the maxillary permanent lateral incisors regularly erupted but lost >3 months prior to the CT scan (TL); and (3) with the maxillary permanent lateral incisors regularly erupted and in situ (control; C). The following parameters were manually recorded by a single calibrated examiner: (1) mesio-distal gap width between the central incisor and the canine; (2) average bucco-palatal alveolar ridge width in the coronal (1st to 5th mm) and apical (6th to 10th mm) part of the alveolar ridge; (3) alveolar ridge bone area from a level 1 mm below the top of the alveolar ridge and 10 mm apically; (4) alveolar ridge height; and (5) possibility of straightforward implant placement (10 mm long x 3 or 3.5 mm in diameter). Further, clinical data regarding the actual treatment performed, i.e. bone grafting prior to- or in association with implant installation, were retrieved from the dental records of the patients of TA. Differences in alveolar ridge dimensions (i.e., bucco-palatal width, area, height) among groups [TA vs. TL vs. C) groups were assessed by One-way-ANOVA with LSD post-hoc test; correlations between the alveolar ridge dimension and the mesio-distal gap width were tested by the Spearman correlation coefficient. Results: Altogether 104 maxillary CT-scans were evaluated; the intended sample size of 40 was not achieved for TL due to frequently uncertain history of tooth loss. The area and bucco-palatal width of the alveolar ridge at the lateral incisor and at the adjacent teeth was significantly reduced in TA compared to TL and C (Table 1). Further, in TA, but not TL, an increasing mesio-distal distance between the adjacent teeth resulted in a significantly reduced bucco-palatal width of the coronal part of the edentulous alveolar ridge (r = −0.464, P = 0.003). This impeded simulated straightforward implant placement in >50% of the cases in TA, even with a reduced implant diameter of 3 mm. This simulation had good agreement with the actual treatment performed. Based on clinical data from 26 patients of the TA group, straightforward implant placement was not possible in 58% of the cases. Conclusions and Clinical Implications: The present results indicate that the wider the mesio-distal gap is in maxillary lateral incisor agenesis sites, the thinner bucco-palatally should the alveolar ridge be expected to be. In particular, a mesio-distal gap of >6 mm precluded straightforward implant placement in 60–80% of the cases. These results are relevant for treatment planning, since additional hard and/or soft tissue augmentation procedures should be frequently expected for optimal functional and aesthetic outcomes.
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| 5. |
- Bertl, Kristina, et al.
(författare)
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A wide mesio-distal gap in sites of congenitally missing maxillary lateral incisors is related to a thin alveolar ridge
- 2017
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Ingår i: Clinical Oral Implants Research. - : John Wiley & Sons. - 0905-7161 .- 1600-0501. ; 28:9, s. 1038-1045
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To evaluate (i) a possible correlation between the mesio-distal gap width and the alveolar ridge (AR) dimensions in patients missing the maxillary lateral incisor (I2) either due to agenesis or loss and (ii) the possibility of straightforward implant placement based on simulation. METHODS: The bucco-palatal width, area, and height of the AR at the position of I2, and the mesio-distal gap width between the central incisor and the canine, were assessed in maxillary CT scans of three groups: Patients with (i) agenesis of I2 (TA ; n = 40); (ii) I2 regularly erupted but extracted (TL ; n = 24); (iii) I2 regularly erupted and in situ (C; n = 40). Further, the possibility of straightforward placement of an implant 3 or 3.5 mm in diameter ×10 mm in length, with 1 mm distance from the buccal and palatal plate of the alveolar ridge was simulated and compared to the actual treatment delivered. RESULTS: Bucco-palatal width and area of the AR at I2 and the adjacent teeth was significantly reduced in TA compared to TL and C. Further, in TA , but not TL , an increasing mesio-distal gap width between the central incisor and canine resulted in a significantly reduced bucco-palatal width of the edentulous AR. This impeded a simulated straightforward implant placement in >50% of the cases in TA , even with a reduced implant diameter. CONCLUSIONS: In patients congenitally missing I2, an increased mesio-distal gap width correlates significantly with reduced edentulous AR dimensions. A mesio-distal gap of >6 mm was associated with thin bucco-palatal alveolar ridges, precluding straightforward implant placement in 60-80% of the cases.
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| 6. |
- Bertl, Kristina, et al.
(författare)
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Alveolar bone resorption after primary tooth loss has a negative impact on straightforward implant installation in patients with agenesis of the lower second premolar
- 2018
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Ingår i: Clinical Oral Implants Research. - : John Wiley & Sons. - 0905-7161 .- 1600-0501. ; 29:2, s. 155-163
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To compare the alveolar bone dimensions in patients with lower second premolar (P2) agenesis prior to and after primary molar loss on CT scans, and assess the possibility for straightforward implant placement. Methods: Alveolar bone dimensions were evaluated on 150 mandibular CT scans in three groups: (i) agenesis of P2, with the primary tooth in situ, and regularly erupted first premolar (P1) and molar (M1) (AW); (ii) agenesis of P2, without the primary tooth in situ for ≥3m, but regularly erupted P1 and M1 (AWO); and (iii) P1, P2, and M1 regularly erupted (CTR). The possibility of straightforward placement of an implant 3.5 or 4.3 mm in Ø × 10 mm long was digitally simulated and compared to the actually performed treatment. Results: Buccolingual width (7.3 ± 2.0 mm) at the coronal aspect of the ridge in the AWO group was statistically significantly smaller comparing with both the AW (9.2 ± 1.4 mm) and the CTR (9.5 ± 1.1 mm) group; width reduction appeared to be mainly due to “collapse” of the buccal aspect of the ridge. Simulated straightforward placement of implants with a diameter of 3.5 or 4.3 mm was possible in 62% and 56% of the cases in the AWO vs. 86% and 84% in the AW group (p = .006 and .002, respectively). Straightforward implant placement was actually possible in all patients (22) in the AW group, while 28% (11 of 39) of the patients in the AWO group needed additional hard tissue augmentation. Conclusions: Significant dimensional differences exist in the alveolar ridge, especially in the coronal part, at lower P2 agenesis sites missing the primary tooth for ≥3m, when compared to P2 agenesis sites with the primary tooth in situ. It seems thus reasonable to advise that the primary second molar should be kept as long as possible, in order to facilitate straightforward implant installation and reduce the probability of additional bone augmentation procedures.
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| 7. |
- Bertl, Kristina, et al.
(författare)
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Bone quantity in patients with agenesis of the lower second premolar evaluated in CT scans
- 2014
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Background Agenesis of a permanent tooth has in Europe a prevalence of 2.6 up to 11.3% and the lower second premolar and the upper lateral incisor are most often affected (except for wisdom teeth). Treatment options are maintenance of the deciduous teeth, implant placement, tooth transplantation, orthodontic treatment for space closure or prosthetic tooth replacement. Especially in the case of agenesis of the lower premolars sand-glass like forms of the mandibular bone are described, which might preclude implant placement without previous augmentation procedures. However, to the best of our knowledge, so far no study is available assessing in detail the mandibular bone quantity in case of agenesis of the lower second premolar compared to a matched control group with regular erupted second premolars. Aim The primary aim was to compare mandibular bone quantity in case of agenesis of the lower second premolar with the deciduous tooth in situ to a matched control group with regularly erupted lower second premolars. Secondly, bone quantity in the region of the mesial and distal adjacent teeth was assessed to receive an overview of the neighbouring bone quantity. Thirdly, the test- and control-group in the region of the second premolar was evaluated on the possibility to place a standard implant. Materials and methods The present study included mandibular CT scans of 100 patients. The test group included 50 patients missing one lower second premolar due to agenesis with the deciduous tooth still in situ. Further, the first premolar and first molar were in situ and regularly erupted. The control group was matched according to age, sex, and tooth’s quadrant and presented regularly erupted first and second premolars and first molars. The dental reconstructions slices in the centre of the first molar and first and second premolar of each participant were used to assess the following parameters: width of the mandibular bone (measured each millimetre starting from the buccal alveolar crest), height and area of the mandibular bone. In the dental reconstruction slices the bony contours were manually retraced, the buccal alveolar crest and the inferior alveolar nerve manually assigned, and the tooth/implant axes indicated. Afterwards, a program for automated image analysis was used for standardised measurements. Further, the possibility of implant placement (4.3mm diameter, 10mm length, 1mm space to the buccal and lingual aspects, 2mm distance to the inferior alveolar nerve) was evaluated. Normal distribution of the data was proven graphically and differences between test and control groups were assessed by independent t-test. The false discovery rate was controlled by applying the Benjamini-Hochberg method and p-values <0.05 were considered as statistically significant. Results Mean width and area of the mandibular bone of the test group were significantly reduced in the region of the first and second premolar compared to the control group. No differences were noticed for the region of the first molar as well as for height measurements. The mean width in the upper third (1-10mm) was not reduced in all three regions. Yet, the mean width of the middle (11-20mm) and of the lower third (>20mm) was significantly reduced in the test group in the region of the first and second premolar, but not of the first molar. In the test group in 42 out of 50 cases (84%) the placement of an implant would have been possible compared to 100% in the control group. Manual linings were performed by a single examiner. This examiner and a second examiner repeated 25% of the whole sample and intra- and inter-examiner observations presented high reliability, with an intra-class correlation coefficient > 0.95. Conclusions and clinical implications In patients with agenesis of the lower second premolar, but deciduous tooth in situ, bone quantity is reduced in the region of the agenesis and at the mesial adjacent tooth. However, bone width is reduced only in an area below the first 10mm, which allows the placement of a standard implant in a high percentage of the cases. In an on-going study these data will be compared to agenesis patients with the deciduous tooth missing to test whether primary tooth maintenance preserves bone quantity.
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| 8. |
- Bertl, Michael Hans, et al.
(författare)
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Impacted and transmigrated mandibular canines : an analysis of 3D radiographic imaging data
- 2018
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Ingår i: Clinical Oral Investigations. - : Springer. - 1432-6981 .- 1436-3771. ; 22:6, s. 2389-2399
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Impacted and transmigrated mandibular canines differ greatly in incidence, etiopathology, associated anomalies, and treatment prospects, when compared to their maxillary counterparts. The aim of this study was to provide a detailed analysis of 3D radiographic imaging data of impacted mandibular canines. MATERIALS AND METHODS: In a retrospective cross-sectional study, CT/CBCT data of 88 patients with a total of 94 impacted mandibular canines were analysed. Evaluated parameters included location, morphology, neighbouring structures, associated anomalies, the influence of those factors on mandibular canine transmigration, as well as applied treatment. RESULTS: Transmigration was found to occur in 40.4% of impacted mandibular canines. Transmigrated canines were located significantly more basally and horizontally angulated. Further, transmigration was significantly associated with a lack of contact to adjacent teeth and the canine's apex not contacting the mandibular cortical bone. The overall incidence of root resorptions of adjacent teeth related to impacted mandibular canines was 7.3% and was more likely, if the canine was lingually impacted. While about half of the non-transmigrated impacted canines were orthodontically aligned, half of the transmigrated canines were surgically removed. Monitoring was the second most applied treatment strategy for both groups, and no canines were autotransplantated. CONCLUSIONS: Root resorption of adjacent teeth and transmigration are commonly occurring phenomena related to impacted mandibular canines. CLINICAL RELEVANCE: Treatment often entails the surgical removal of the canine-especially in cases of transmigration. The findings emphasise the importance of early diagnosis and CT/CBCT imaging for further diagnostics and future research of impacted mandibular canines.
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| 9. |
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| 10. |
- Bertl, Michael Hans, et al.
(författare)
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Second premolar agenesis is associated with mandibular form : a geometric morphometric analysis of mandibular cross-sections
- 2016
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Ingår i: International Journal of Oral Science. - : Nature Publishing Group. - 1674-2818 .- 2049-3169. ; 8, s. 254-260
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to compare mandibular form (i.e., size and shape) between patients with agenesis of the lower second premolar (P2) and a control group with no agenesis. Three hypotheses were tested: (H1) agenesis causes a change in mandibular morphology because of inadequate alveolar ridge development in the area of the missing tooth (mandibular plasticity); (H2) agenesis is caused by spatial limitations within the mandible (dental plasticity); and (H3) common genetic/ epigenetic factors cause agenesis and affect mandibular form (pleiotropy). A geometric morphometric analysis was applied to cross-sectional images of computed tomography (CT) scans of three matched groups (n = 50 each): (1) regularly erupted P2; (2) agenesis of P2 and the primary second molar in situ; and (3) agenesis of P2 and the primary second molar missing for 43 months. Cross-sections of the three areas of interest (first premolar, P2, first molar) were digitized with 23 landmarks and superimposed by a generalized Procrustes analysis. On average, the mandibular cross-sections were narrower and shorter in patients with P2 agenesis compared with that in the control group. Both agenesis groups featured a pronounced submandibular fossa. These differences extended at least one tooth beyond the agenesis-affected region. Taken together with the large interindividual variation that resulted in massively overlapping group distributions, these findings support genetic and/or epigenetic pleiotropy (H3) as the most likely origin of the observed covariation between mandibular form and odontogenesis. Clinically, reduced dimensions and greater variability of mandibular form, as well as a pronounced submandibular fossa, should be expected during the treatment planning of patients with P2 agenesis.
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