relate tooth alveolar extraction socket anatomy to alveolar remodeling rate

Conditions: Loss of Teeth Due to Extraction; Alveolar Bone Loss; Bone Resorption

Summary: in patients that are going to be subjected to a tooth extraction in the anterior maxillary (from canine to canine) does the position of the intact alveolar socket related to maxillary basal bone interferes with the rate of resorption and remodeling process of the alveolar ridge ?

we intend to demonstrate the physiologic process of the post-extraction socket and we hypothesized that the position of the socket in relation to basal bone, may project the remodeling process through three different equations. a- tooth-periodontal apparatus is placed buccally of the basal bone - equation 1 anatomy features- only 1-2 mm of lamina dura on the buccal part, 1-2mm of lamina dura on the palatal, plus basal bone. physiologic features - when the alveolar apparatus remodels, after tooth extraction, the amount that we project for resorption is : 1-2 mm of buccal lamina dura, the buccal-palatal dimension of the tooth that was extracted plus the 1-2 mm of palatal lamina dura. at 6 month we hypothesized that 3 mm of trabecular bone may be present, so we may account for 2-3 mm more. due to conical anatomy of anterior teeth, the amount of trabecular bone will be more pronounced in the coronal area than in apical area, so we also account for that variation. at this stage we project that the amount of ridge dimension will be : buccal soft tissue (bst) + trabecular alveolar bone (atb) + basal bone (bb) + palatal soft tissue (pst) equation at 6 month = (bst + atb + pst). but at 1 year the trabecular bone may be absent, so we project that the equation will be : buccal soft tissue+basal bone+palatal soft tissue. equation at 1 year (bst + bb + pst) at the end, ridge dimension will be : palatal basal bone plus soft tissue buccally and palatally. numbers for buccal placed alveolus apparatus : at pre-extraction appointment (estimate) : bst+ lamina dura buccal + tooth buccal lingual dimension + palatal lamina dura + bb + pst (3mm + 1mm + x+ 1mm + y + 3mm) = 8 mm + x (a or b or c) + y (a or b or c) x = for anterior teeth= 3 measures = coronal (xa) + middle (xb) + apical (xc) y- basal bone is genetically predetermined and vary from person to person but geometrically can have two measures one middle (ya) and one apical (yb) note : the buccal-lingual dimensions vary from coronal to apical (either in the tooth root and in basal bone), so we hypothesize that the subtraction from pre-extraction values to post-extraction will more pronounced in coronal area than in the apical area. at 6 month post-extraction : bst+ atb (varies coronal (a) , middle (b) , apical (c)) + bb + pst (3mm + atb (a or b or c) + y + 3mm) = 6 mm + atb (a or b or c) + y (a or b) at 1 year post-extraction bst + bb + pst (3mm + x1 + 3mm) = 6 mm + y (a or b ) example for central incisor : before extraction (estimate) at coronal part pre-extraction : 3 + 1 + 10 (xa) + 1 + 3 (ya) + 3 = 21 mm at middle part pre-extraction : 3 + 1 + 5 (xb) + 1 + 5 (yb) + 3 = 18 mm at apical part pre-extraction : 3 + 1 + 2 (xc) + 1 + 8 (yc) + 3 = 18 mm after extraction 6 month (estimate) at coronal part post-extraction : 3 + 3 (atba) + 3 + 3 = 12 mm at middle part post-extraction : 3 + 2 (atbb) + 5 + 3 = 13 mm at apical part post-extraction : 3 + 1 (atbc) + 8 + 3 = 15 mm variation expected (estimate) from pre-extraction to 6 month post-extraction in buccally placed alveolar socket will be (estimate): at coronal part ⨺ (variation) = 9 mm (43% reduction) at middle part ⨺ (variation) = 5 mm (28% reduction) at middle part ⨺ (variation) = 3 mm (17% reduction) after extraction 1 year (estimate) at coronal part post-extraction : 3 + 3 + 3 = 9 mm at middle part post-extraction : 3 + 5 + 3 = 11 mm at apical part post-extraction : 3 + 8 + 3 = 14 mm variation expected (estimate) from pre-extraction to 1 year post extraction in buccally placed alveolar socket will be: at coronal part ⨺ (variation) = 12 mm (57% reduction) at middle part ⨺ (variation) = 7 mm (39% reduction) at middle part ⨺ (variation) = 4 mm (22% reduction) b- tooth-periodontal apparatus is inferior of the basal bone (true socket) - equation 2 anatomy features- only 1-2 mm of lamina dura on the buccal and palatal part, no basal bone palatal, the basal bone is superior to the alveolar process. physiologic features - when the alveolar apparatus remodels after tooth extraction we project that the amount of resorption will be 1-2 mm of buccal lamina dura, the buccal-palatal dimension of the tooth that was extracted, plus the 1-2 mm of palatal lamina dura. at 6 month, we hypothesized that 3 mm of trabecular bone may be present, so we may account for 2-3 mm more. at this stage the amount of ridge dimension will be composed by : buccal soft tissue (bst) + trabecular alveolar bone (atb) + palatal soft tissue (pst), (bst+atb+pst). note : lamina dura disappears, but because periosteum has to adhere to bone an outer cortical forms that surrounds remaining trabecular bone. numbers for inferior placed alveolus apparatus : at pre-extraction appointment (estimate) : bst+ lamina dura buccal + tooth buccal-lingual dimension + palatal lamina dura + pst equation = (3mm + 1mm + x+ 1mm + 3mm) = 8 mm + x (a or b or c) x = for anterior teeth = 3 measures = coronal (xa) + middle (xb) + apical (xc) note : the buccal-lingual dimensions vary from coronal to apical (either in the tooth root and in basal bone), so we hypothesize that the subtraction from pre-extraction values to post-extraction will more pronounced in coronal area than in the apical area at 6 month post-extraction (estimate) : bst+ atb (varies coronal (a) , middle (b) , apical (c) + pst equation = (3mm + atb (a or b or c) + 3mm) = 6 mm + atb (a or b or c) at 1 year post-extraction (estimate) bst + atb (a or b or c) + pst (3mm + x1 + 3mm) = 6 mm + atb (a or b or c) example for central incisor : before extraction (estimate) at coronal part pre-extraction : 3 + 1 + 10 (xa) + 1 + 3 = 18 mm at middle part pre-extraction : 3 + 1 + 5 (xb) + 1 + 3 = 13 mm at apical part pre-extraction : 3 + 1 + 2 (xc) + 1 + 3 = 10 mm after extraction 6 month (estimate) at coronal part post-extraction : 3 + 3 (atba) + 3 = 9 mm at middle part post-extraction : 3 + 2 (atbb) + 3 = 8 mm at apical part post-extraction : 3 + 1 (atbc) + 3 = 7 mm variation expected (projected) from pre-extraction to 6 month post-extraction in inferior placed alveolar socket will be (estimate): at coronal part ⨺ (variation) = 9 mm (43% reduction) at middle part ⨺ (variation) = 5 mm (28% reduction) at middle part ⨺ (variation) = 3 mm (17% reduction) after extraction 1 year (estimate) at coronal part post-extraction : 3 + 2 + 3 = 8 mm at middle part post-extraction : 3 + 2 + 3 = 8 mm at apical part post-extraction : 3 + 2 + 3 = 8 mm variation expected (estimate) from pre-extraction to 1 year post-extraction in inferior placed alveolar socket will be: at coronal part ⨺ (variation) = 10 mm (57% reduction) at middle part ⨺ (variation) = 5 mm (38% reduction) at middle part ⨺ (variation) = 2 mm (20% reduction) c- tooth-periodontal apparatus is in (imbedded) the basal bone - equation 3 anatomy features- only 1-2 mm of lamina dura on the buccal part, 1-2mm of lamina dura on the palatal plus basal bone on the buccal and on the lingual part. physiologic features - when the alveolar apparatus remodels after tooth extraction, we project that the amount of resorption will be 1-2 mm of buccal lamina dura the buccal-palatal dimension of the tooth that was extracted plus the 1-2 mm of palatal lamina dura. at 6 month, we hypothesized that 3 mm of trabecular bone may be present so we may account for 2-3mm more. at this stage the amount of ridge dimension will be composed by: buccal soft tissue (bst) + buccal basal bone (bbb) + trabecular alveolar bone (atb)+ palatal basal bone (lbb)+ palatal soft tissue (pst), equation = (bst+bbb+atb+pbb+pst) numbers for imbedded alveolus apparatus : at pre-extraction appointment (estimate): bst+ bbb (y1 a or b or c) + lamina dura buccal + tooth buccal lingual dimension (x a or b or c) + palatal lamina dura + pbb (y2 a or b or c or d) + pst (3mm + 1mm + x+ 1mm + 3mm) = 8 mm +y1 + x (a or b or c or d) +y2 x = for anterior teeth = 3 measures = coronal (xa) + middle (xb) + apical (xc) y1- buccal basal bone is genetically predetermined and vary from person to person geometrically 3 measures coronal (a) middle (b) and apical (c) y2- palatal basal bone (pbb) is genetically predetermined and vary from person to person geometrically 3 measures coronal (a) middle (b) and apical (c) note : the buccal-lingual dimensions vary from coronal to apical (either in the tooth root and in basal bone), so we hypothesize that the subtraction from pre-extraction values to post-extraction will more pronounced in coronal area than in the apical area at 6 month post-extraction (estimate): bst+ bbb (y1 a or b or c) + atb (varies coronal (a) , middle (b) , apical (c)) + pbb (y2 a or b or c) + pst (3mm + y1+ atb (a or b or c) + y2 + 3mm) = 6 mm + atb (a or b or c) at 1 year post-extraction (estimate) bst+ bbb (y1 a or b or c) + atb (a or b or c) + pbb (y2 a or b or c) + pst (3mm + x1 + 3mm) = 6 mm + y1 (a or b or c) + atb (a or b or c) + + pbb (y2 a or b or c) example for central incisor : before extraction (estimate) at coronal part pre-extraction : 3 + 3 + 1 + 10 (xa) + 1 + 3 + 3 = 24 mm at middle part pre-extraction : 3 + 5 + 1+ 5 (xb) + 1 + 5 + 3 = 23 mm at apical part pre-extraction : 3 + 8 + 1 + 2 (xc) + 1 + 8 + 3 = 26 mm after extraction 6 month (estimate) at coronal part post-extraction : 3 + 3 + 10 (atba) + 3 + 3 = 22 mm at middle part post-extraction : 3 + 5 + 5 (atbb) + 5 + 3 = 21 mm at apical part post-extraction : 3 + 8 + 2 (atbc) + 8 + 3 = 24 mm variation expected (estimate) from pre-extraction to 6 month post-extraction in imbedded placed alveolar socket will be: at coronal part ⨺ (variation) = 2 mm (8% reduction) at middle part ⨺ (variation) = 2 mm (8% reduction) at middle part ⨺ (variation) = 2 mm (8% reduction) after (estimate) extraction 1 year at coronal part post-extraction : 3 + 3? + 10 + 3 ?+ 3 = 14 mm at middle part post-extraction : 3 + 5?+ 5 + 5? + 3 = 18 mm at apical part post-extraction : 3 + 8 ? + 2 + 8? + 3 = 8 mm variation expected (estimate) from pre-extraction to 1 year post-extraction in imbedded placed alveolar socket will be: at coronal part ⨺ (variation) = 2 mm (8% reduction) at middle part ⨺ (variation) = 2 mm (8% reduction) at middle part ⨺ (variation) = 2 mm (8% reduction)

Eligibility criteria:
inclusion criteria: * patient that require a maxillary anterior extraction * sign informed consent * indication for a two-stage implant placement exclusion criteria: * indication for immediate implants * indication for alveolar socket preservation or bone regeneration * indication for soft tissue graft * diabetes * taking oral or intravenous biphosphonates

Keywords: extraction sockets ridge dimensions dental alveolar anatomy dental implants bone physiology